--- /dev/null
+ATARI
+-----
+MADMAC
+======
+68000 Macro Assembler
+=====================
+Reference Manual
+================
+version 1.00
+============
+
+::
+
+ MADMAC Version 1.07 release notes, January, 1990.
+
+
+ Using .cargs used to cause subsequent global symbols to disappear from
+ the symbol table. Now it doesn't.
+
+
+ A movem instruction with no register list (i.e. "movem.l (sp)+,")
+ assembled without error; it now reports "missing regsiter list."
+
+
+
+
+
+
+
+
+
+
+
+::
+
+ MADMAC Version 1.05 release notes, August, 1988.
+
+
+ This version of MadMac replaces version 1.00 and fixes some small bugs:
+
+
+ Symbols beginning with a capital L were not included in the
+ object file output. They should have been (and now are) excluded only
+ in AS68 compatibility mode, to avoid cluttering the output with
+ compiler-generated symbols.
+
+
+ Forward branches declared "short" (such as bras, dbra.s, bsr.$)
+ but whose targets were too far away did not cause an assembly-time
+ error; incorrect machine code was silently generated. They now cause
+ assembly-time errors.
+
+
+ Symbols appeared in the object file symbol table in the order •
+ they were referenced in the source, not the order they were declared.
+ Now the order more nearly matches the order of declaration (but not
+ perfectly).
+
+
+ The disp(And(n.$) addressing mode produced correct machine code,
+ but incorrect output in the listing file. Now the output is correct.
+
+
+*NOTE: Every effort has been made to ensure the accuracy and robustness of this
+manual and the associated software. However, because Atari Corporation is con-
+stantly improving and updating its computer software, it is unable to guarantee
+the accuracy of printed or duplicated material after the date of publication and
+disclaims liability for changes, errors or omissions.*
+
+
+
+
+
+
+
+
+
+
+
+
+ATARI, the Atari logo, MEGA, and ST are trademarks or registered trademarks of
+Atari Corporation.
+Mark Williams is a trademark of Mark Williams Company.
+Motorola is a trademark of Motorola Inc.
+
+
+
+
+
+
+
+
+
+
+
+*Copyright © 1986, 1987, Atari Corporation*
+
+*All rights reserved.*
+
+*Reproduction of this document or the associated software is not allowed without
+the specific written consent of Atari Corporation.*
+
+*Printed in USA.*
+
+*Atari Document number C300341-001 Rev. A.*
+
+Contents
+========
+
+.. contents::
+
+Introduction
+============
+
+Introduction
+''''''''''''
+This document describes MADMAC, a fast macro assembler for the 68000. MADMAC currently
+runs on the Atari ST and under 4.2 BSD VAX UNIX. It was written
+at Atari Corporation by programmers who needed a high performance assembler
+for their work.
+
+MADMAC is intended to be used by programmers who write mostly in assembly language.
+It was not originally a back-end to a C compiler, therefore it
+has creature comfort that are usually neglected in such back-end assemblers. It
+supports include files, macros, symbols with limited scope, some limited control
+structures, and other features. MADMAC is also blindingly fast, another feature
+often sadly and obviously missing in today's assemblers.[1]_
+
+MADMAC is not entirely compatible with the AS68 assembler provided with
+the original Atari ST Developer's Kit, but most changes are minor and a few minutes
+with an editor should allow you to assemble your current source files. If you are an
+AS68 user, before you leap into the unknown please read the section on Notes for
+AS68 Users.
+
+This manual was typeset with TEX and the Computer Modern fonts, and it
+was printed on the Atari SLM-804 laser printer with a MEGA ST. Except for 200
+lines of assembly language, the assembler is written entirely in C.
+
+`Getting Started`_
+''''''''''''''''''
+
+ =>Write protect your distribution disk and make a backup of it now. Put the
+ original disk in a safe place.
+
+* The distribution disk contains a file called README that you should read.
+ This file contains important nays about the contents of the distribution disk
+ and summarizes the most recent changes to the tools.
+
+* Hard disk users can simply copy the executable files to their work or binary
+ directories. People with floppy disks can copy the executables to ramdisks,
+ install the assembler with the -q option, or even work right off of the floppies.
+
+* You will need an editor that can produce "normal" format text files. Micro
+ Emacs will work well, as will most other commercial program editors, but not
+ most word processors (such as First Word or Microsoft Write).
+
+* You will probably want to examine or get a listing of the file "ATARI.S". It
+ contains lots of definitions for the Atari ST, including BIOS variables, most
+ BIOS, XBIOS and GEMDOS traps, and line-A equates. We (or you) could
+ split the file up into pieces (a file for line-A equates, a file for hardware and
+ BIOS variables and so on), but MADMAC is so fast that it doesn't matter
+ much.
+
+* Read the rest of the manual, especially the first two chapters on The Com-
+ mand Line and Using MADMAC. The distribution disk contains example
+ programs that you can look at, assemble and modify.
+
+.. [1] It processes 30,000 lines a minute on a lightly loaded VAX 11/780; maybe 40,000 on a 520-ST with an SH-204 hard disk. Yet it could be sped up even more with some effort and without resorting to assembly language; C doesn't have to be slow!
+
+
+`The Command Line`_
+'''''''''''''''''''
+
+The assembler is called "**mac.prg**". The command line takes the form:
+
+ **mac** [*switches*] [*files* ...]
+
+A command line consists of any number of switches followed by the names of files
+to assemble. A switch is specified with a dash (**-**) followed immediately by a key
+character. Key characters are not case-sensitive, so "**-d**" is the same as "**-D**". Some
+switches accept (or require) arguments to immediately follow the key character,
+with no spaces in between.
+
+Switch order is important. Command lines are processed from left to right in
+one pass, and switches usually take effect when they are encountered. In general it
+is best to specify all switches before the names of any input files.
+
+If the command line is entirely empty then MADMAC prints a copyright message
+and enters an "interactive" mode, prompting for successive command lines
+with a star (\*). An empty command line will exit (See the examples in the chapter
+on `Using MADMAC`_). After each assembly in interactive mode, the assembler
+will print a summary of the amount of memory used, the amount of memory left,
+the number of lines processed, and the number of seconds the assembly took.
+
+Input files are assumed to have the extension "**.s**"; if a filename has no extension
+(i.e. no dot) then "**.s**" will be appended to it. More than one source filename may be
+specified: the files are assembled into one object file, as if they were concatenated.
+
+MADMAC normally produces object code in "**file.o**" if "**file.s**" is the first
+input filename. If the first input file is a special character device, the output name
+is noname.o. The **-o** switch (see below) can be used change the output file name.
+
+
+=================== ===========
+Switch Description
+=================== ===========
+-dname\ *[=value]* Define symbol, with optional value.
+-e\ *[file[.err]]* Direct error messages to the specified file.
+-fm Produce Mark Williams format object file.
+-fmu Like "**-fm**" , but move underscores to end of symbol names.
+-i\ *path* Set include-file directory search path.
+-l\ *[file[prn]]* Construct and direct assembly listing to the specified file.
+-o\ *file[.o]* Direct object code output to the specified file.
+-p Produce an executable (**.prg**) output file.
+-ps Produce an executable (**.prg**) output file with symbols.
+-q Make MADMAC resident in memory (Atari ST only).
+-s Warn about unoptimized long branches.
+-u Assume that all undefined symbols are external.
+-v Verbose mode (print running dialogue).
+-yn Set listing page size to n lines.
+-6 "Back end" mode for Alcyon C68.
+file\ *[s]* Assemble the specified file.
+=================== ===========
+
+The switches are described below. A summary of all the switches is given in
+the table.
+
+**-d**
+ The **-d** switch permits symbols to be defined on the command line. The name
+ of the symbol to be defined immediately follows the switch (no spaces). The
+ symbol name may optionally be followed by an equals sign (=) and a decimal
+ number. If no value is specified the symbol's value is zero. The symbol at-
+ tributes are "defined, not referenced, and absolute". This switch is most useful
+ for enabling conditionally-assembled debugging code on the command line; for
+ example:
+
+ ::
+
+ -dDEBUG -dLoopCount=999 -dDebugLevel=55
+
+**-e**
+ The -e switch causes MADMAC to send error messages to a file, instead of the
+ console. If a filename immediately follows the switch character, error messages
+ are written to the specified file. If no filename is specified, a file is created with
+ the default extension "**.err**" and with the root name taken from the first input
+ file name (e.g. error messages are written to "**file.err**" if "**file**" or "**file.s**" is
+ the first input file name). If no errors are encountered, then no error listing
+ file is created. Beware! If an assembly produces no errors, any error file from
+ a previous assembly is not removed.
+
+**-fm**
+
+**-fmu**
+ The **-fm** and **-fmu** switches cause MADMAC to generate Mark Williams style
+ object files instead of Alcyon object files. These files may be linked with the
+ Mark Williams linker. The **-fmu** switch causes underscores on the first char-
+ acter of a global symbol name to be moved to the end of the name, as per the
+ Mark Williams C compiler naming convention. That is, "**_main**" will become
+ "**main\_**" and "**__main**" will become "**_main_**".
+**-i**
+ The **-i** switch allows automatic directory searching for include files. A list of
+ semi-colon seperated directory search paths may be mentioned immediately
+ following the switch (with no spaces anywhere). For example:
+
+ ::
+
+ -im:;c:include;c:include\sys
+
+ will cause the assembler to search the current directory of device **M**, and the
+ directories include and include\sys on drive **C**. If *-i* is not specified, and the
+ enviroment variable "**MACPATH**" exists, its value is used in the same manner.
+ For example, users of the Mark Williams shell could put the following line in
+ their profile script to achieve the same result as the **-i** example above:
+
+ ::
+
+ setenv MACPATH="m:;c:include;c:include\sys"
+**-l**
+ The -l switch causes MADMAC to generate an assembly listing file. If a file-
+ name immediately follows the switch character, the listing is written to the
+ specified file. If no filename is specified, then a listing file is created with the
+ default extension "**.prn**" and with the root name taken from the first input file
+ name (e.g. the listing is written to "**file.prn**" if "**file**" or "**file.s**" is the first
+ input file name).
+**-o**
+ The -o switch causes MADMAC to write object code on the specified file. No
+ default extension is applied to the filename. For historical reasons the filename
+ can also be seperated from the switch with a space (e.g. "**-o file**").
+
+**-p**
+
+**-ps**
+ The **-p** and **-ps** switches cause MADMAC to produce an Atari ST executable
+ file with the default extension of "**.prg**". If there are any external references
+ at the end of the assembly, an error message is emitted and no executable file
+ is generated. The **-p** switch does not write symbols to the executable file. The
+ **-ps** switch includes symbols (Alcyon format) in the executable file.
+**-q**
+ The **-q** switch is aimed primarily at users of floppy-disk-only systems. It causes
+ MADMAC to install itself in memory, like a RAMdisk. Then the program
+ **m.prg** (which is very short - less than a sector) can be used instead of
+ **mac.prg**, which can take ten or twelve seconds to load.
+**-s**
+ The **-s** switch causes MADMAC to generate a list of unoptimized forward
+ branches as warning messages. This is used to point out branches that could
+ have been short (e.g. "bra" could be "bra.s").
+**-u**
+ The **-u** switch takes effect at the end of the assembly. It forces all referenced
+ and undefined symbols to be global, exactly as if they had been made global
+ with a **.extern** or **.globl** directive. This can be used if you have a lot of
+ external symbols, and you don't feel like declaring them all external.
+**-v**
+ The **-v** switch turns on a "verbose" mode in which MADMAC prints out (for
+ example) the names of the files it is currently processing. Verbose mode is
+ automatically entered when MADMAC prompts for input with a star.
+**-y**
+ The **-y** switch, followed immediately by a decimal number (with no intervening
+ space), sets the number of lines in a page. MADMAC will produce *N* lines
+ before emitting a form-feed. If *N* is missing or less than 10 an error message is
+ generated.
+**-6**
+ The **-6** switch takes effect when it is mentioned. It allows MADMAC to be
+ used as a back end to the Alcyon C compiler.\ [2]_ **Note:** the assembler will
+ produce code that is typically ten percent larger and ten percent slower than
+ the output of the Alcyon assembler, therefore use of this switch for production
+ code is discouraged.
+
+.. [2] The -6 switch is not a compatibility mode for AS68 - it has been carefully tailored to accept the output of the Alcyon C compiler.
+
+
+`Using MADMAC`_
+===============
+
+Let's assemble and link some example programs. These programs are included
+on the distribution disk in the "**EXAMPLES**" directory - you should copy them to
+your work area before continuing. In the following examples we adopt the conven-
+tions that the shell prompt is a percent sign (%) and that your input (the stuff you
+type) is presented in **bold face**.
+
+If you have been reading carefully, you know that MADMAC can generate
+an executable file without linking. This is useful for making small, stand alone
+programs that don't require externals or library routines. For example, the following
+two commands:
+
+ ::
+
+ % mac examples
+ % aln -s example.s
+
+could be replaced by the single command:
+
+ ::
+
+ % mac -ps example.s
+
+since you don't need the linker for stand-alone object files.
+
+Successive source files named in the command line are are concatenated, as in
+this example, which assembles three files into a single executable, as if they were
+one big file:
+
+ ::
+
+ % mac -p bugs shift images
+
+Of course you can get the same effect by using the **.include** directive, but sometimes
+it is convenient to do the concatenation from the command line.
+
+ Here we have an unbelievably complex command line:
+
+ ::
+
+ % mac -lzorf -y95 -o tmp -ehack -Ddebug=123 -ps example
+
+This produces a listing on the file called "**zorf.prn**" with 95 lines per page, writes
+the executable code (with symbols) to a file called "**tmp.prg**", writes an error listing
+to the file "**hack.err**", specifies an include-file path that includes the current
+directory on the drive "**M:**," defines the symbol "**debug**" to have the value 123, and
+assembles the file "**example.s**". (Take a deep breath - you got all that?)
+
+One last thing. If there are any assembly errors, MADMAC will terminate
+with an exit code of 1. If the assembly succeeds (no errors, although there may be
+warnings) the exit code will be 0. This is primarily for use with "make" utilities.
+
+`Interactive Mode`_
+'''''''''''''''''''
+If you invoke MADMAC with an empty command line it will print a copyright
+message and prompt you for more commands with a star (*****). This is useful if you
+are used to working directly from the desktop, or if you want to assemble several files
+in succession without having to reload the assembler from disk for each assembly.
+
+In interactive mode, the assembler is also in verbose mode (just as if you had
+specified **-v** on each command line):
+
+ ::
+
+ %. mac
+
+ MADMAC Atari Macro Assembler
+ Copyright 1987 Atari Corporation
+ Beta version 0.12 Jun 1987 lmd
+
+ * -ps example
+ [Including: example.s]
+ [Including: atari.s]
+ [Leaving: atari.s]
+ [Leaving; example. a]
+ [Writing executable tile: example.prg
+ 36K used, 3868K left, 850 lines, 2.0 seconds
+
+
+You can see that the assembler gave a "blow-by-blow" account of the files it processed,
+as well as a summary of the assembly's memory usage, the number of lines
+processed (including macro and repeat-block expansion), and how long the assembly
+took
+
+The assembler prompts for another command with the star. At this point you
+can either type a new command line for the assembler to process, or you can exit
+by typing control-C or an empty line.
+
+Things You Should Be Aware Of
+'''''''''''''''''''''''''''''
+MADMAC is a one pass assembler. This means that it gets all of its work done by
+reading each source file exactly once and then "back-patching" to fix up forward
+references. This one-pass nature is usually transparent to the programmer, with
+the following important exceptions:
+
+ o in listings, the object code for forward references is not shown. Instead, lower-
+ case "xx"s are displayed for each undefined byte, as in the following example:
+
+ ::
+
+ 60xx 1: bra.s.2 ;forward branch
+ xxxxxxxx dc.l .2 ;forward reference
+ 60FE .2: bra.s.2 ;backward reference
+
+ o Forward branches (including **BSR**\s) are never optimized to their short forms.
+ To get a short forward branch it is necessary to explicitly use the ".s" suffix in
+ the source code.
+ o Error messages may appear at the end of the assembly, referring to earlier source
+ lines that contained undefined symbols.
+ o All object code generated must fit in memory. Running out of memory is a
+ fatal error that you must deal with by splitting up your source files, re-sizing
+ or eliminating memory-using programs such as ramdisks and desk accessories,
+ or buying more RAM.
+
+Forward Branches
+''''''''''''''''
+MADMAC does not optimize forward branches for you, but it will tell you about
+them if you use the -s (short branch) option:
+
+ ::
+
+ % mac -s example.s
+ "example.s", line 20: warning: unoptimized short branch
+
+With the -e option you can redirect the error output to a file, and determine by
+hand (or editor macros) which forward branches are safe to explicitly declare short.
+
+Notes for AS68 Users
+''''''''''''''''''''
+MADMAC is not entirely compatible with the Alcyon assembler, AS68. This section
+outlines the major differences. In practice, we have found that very few changes are
+necessary to make AS68 source code assemble.
+
+ o A semicolon (;) must be used to introduce a comment, except that a star (*)
+ may be used in the first column. AS68 treated anything following the operand
+ field, preceeded by whitespace, as a comment. (MADMAC treats a star that
+ is not in column 1 as a multiplication operator).
+
+ o Labels require colons (even labels that begin in column 1).
+
+ o Conditional assembly directives are called **if**, **else** and **endif**. AS68 called these
+ **ifne**, **ifeq** (etc.), and **endc**.
+ o The tilde (~) character is an operator, and back-quote (`) is an illegal character.
+ AS68 permitted the tilde and back-quote characters in symbols.
+ o There are no equivalents to AS68's org or section directives. AS68's page
+ directive has become eject. The AS68 **.xdef** and **.xref** directives are not implemented,
+ but **.globl** makes these unnecessary anyway. The directives **.comline**,
+ **mask2**, **idnt** and **opt**, which were unimplemented and ignored in AS68, are
+ not legal in MADMAC.
+
+ o The location counter cannot be manipulated with a statement of the form:
+
+ ::
+
+ * = expression
+
+ o The **ds** directive is not permitted in the text or data segments (except in **-6**
+ mode); an error message is issued. Use **dcb** instead to reserve large blocks of
+ initialized storage.
+
+ o Back-slashes in strings are "electric" characters that are used to escape C-like
+ character codes. Watch out for GEMDOS path names in ASCII constants -
+ you will have to convert them to double-backslashes.
+
+Notes for Mark Williams C Users
+'''''''''''''''''''''''''''''''
+MADMAC will generate object code that the Mark Williams C linker, **ld**, will
+accept. This has been tested only with version 2.0 of the Mark Williams package.
+Some notable differences between MADMAC and the Mark Williams assembler, as,
+are:
+
+ o MWC permits 16-character symbol names in the object file, and MADMAC
+ supports this;
+ o MWC object files can contain more code and data sections than the MADMAC
+ (Alcyon) object code format. MADMAC maps its code sections as follows:
+
+================================ ==================
+MWC Space MADMAC Space
+================================ ==================
+shui (shared instruction) text
+prvi (private instruction) unsupported
+bssi (uninitialized instruction) unsupported
+shrd (shared data) data
+prvd (private data) unsupported
+bssd (uninitialized data) bss
+debug information unsupported
+symbols symbols
+absolute abs, equates, etc.
+================================ ==================
+
+ It is not possible for MADMAC to generate code in the Mark Williams private
+ instruction, private data or uninitialized instruction spaces.
+
+ o None of the Mark Williams assembler directives (e.g. "**.long**" and "**.odd**") are
+ supported. None of the MWC non-standard addressing modes are supported.
+ o The Mark Williams debugger, **db**, does not support the Alcyon-format symbols
+ produced with the **-ps** switch; it complains about the format of the executable
+ file and aborts.
+ o MADMAC does not support the method by which the Mark Williams shell
+ passes long command lines to programs. Command lines are truncated to 127
+ characters.
+
+Using MADMAC as a Back-End to the Alcyon C Compiler
+'''''''''''''''''''''''''''''''''''''''''''''''''''
+MADMAC can be used in place of the AS68 assembler as a back-end for the Alcyon
+version 4.14 C compiler. The "**-6**" switch turns on a mode that warps and perverts
+MADMAC's ordinary syntax into accepting what the Alcyon compiler dishes out.
+This can be used in a batch file (for instance) with a line that looks like:
+
+ ::
+
+ mac -6 -o %1.o m:%1
+
+(Assuming that device "**M:**" is where the source was put by compiler phase **c168**).
+You should be aware that AS68 generally produces better and faster code than
+MADMAC, although it is slower to assemble.
+
+`Text File Format`_
+'''''''''''''''''''
+For those using editors other than the "Emacs" style ones (Micro-Emacs, Mince,
+etc.) this section documents the source file format that MADMAC expects.
+
+ o Files must contain characters with ASCII values less than 128; it is not per-
+ missable to have characters with their high bits set unless those characters are
+ contained in strings (i.e. between single or double quotes) or in comments.
+
+ o Lines of text are terminated with carriage-return/line-feed, linefeed alone, or
+ carriage-return alone.
+
+ o The file is assumed to end with the last terminated line. If there is text beyond
+ the last line terminator (e.g. control-Z) it is ignored.
+
+`Source Format`_
+================
+
+`Statements`_
+'''''''''''''
+A statement may contain up to four fields which are identified by order of ap-
+pearance and terminating characters. The general form of an assembler statement
+is:
+
+ ::
+
+ label: operator operand(s) ; comment
+
+The label and comment fields are optional. An operand field may not appear
+without an operator field. Operands are seperated with commas. Blank lines are
+legal. If the first character on a line is an asterisk (*) or semicolon (;) then the
+entire line is a comment. A semicolon anywhere on the line (except in a string)
+begins a comment field which extends to the end of the line.
+
+The label, if it appears, must be terminated with a single or double colon. If
+it is terminated with a double colon it is automatically declared global. It is illegal
+to declare a confined symbol global (see: `Symbols and Scope`_).
+
+`Equates`_
+''''''''''
+A statement may also take one of these special forms:
+
+ *symbol* **equ** *expression*
+
+ *symbol* **=** *expression*
+
+ *symbol* **--** *expression*
+
+ *symbol* **set** *expression*
+
+ *symbol* **reg** *register list*
+
+The first two forms are identical; they equate the symbol to the value of an
+expression, which must be defined (no forward references). The third form, double-
+equals (==), is just like an equate except that it also makes the symbol global. (As
+with labels, it is illegal to make a confined equate global.) The fourth form allows
+a symbol to be set to a value any number of times, like a variable. The last form
+equates the symbol to a 16-bit register mask specified by a register list. It is possible
+to equate confined symbols (see: `Symbols and Scope`_). For example:
+
+ ::
+
+ cr equ 13 carriage-return
+ if = 10 line-feed
+ DEBUG == 1 global debug flag
+ count set 0 variable
+ count set count + 1 increment variable
+ .rags reg d3-d7/a3-a6 register list
+ .cr 13 confined equate
+
+`Symbols and Scope`_
+''''''''''''''''''''
+Symbols may start with an uppercase or lowercase letter (A-Z a-z), an underscore
+(**_**), a question mark (**?**) or a period (**.**). Each remaining character may be an
+upper or lowercase letter, a digit (**0-9**), an underscore, a dollar sign (**$**), or a question
+mark. (Periods can only begin a symbol, they cannot appear as a symbol
+continuation character). Symbols are terminated with a character that is not a
+symbol continuation character (e.g. a period or comma, whitespace, etc.). Case is
+significant for user-defined symbols, but not for 68000 mnemonics, assembler direc-
+tives and register names. Symbols are limited to 100 characters. When symbols
+are written to the object file they are silently truncated to eight (or sixteen) char-
+acters (depending on the object file format) with no check for (or warnings about)
+collisions.
+
+ For example, all of the following symbols are legal and unique:
+
+ ::
+
+ reallyLougSymbolliame .reallyLongConfinadSymbollame
+ al0 ret move dc frog aae a9 ????
+ .al .ret .move .dc .frog .a9 .9 ????
+ .0 .00 .000 .1 .11. .111 . ._
+ _frog ?zippo? sys$syetem atari Atari ATARI aTaRi
+
+while all of the following symbols are illegal:
+
+ ::
+
+ 12days dc.10 dc.z 'quote .right.here
+ @work hi.there $money$ ~tilde
+
+
+Symbols beginning with a period (**.**) are *confined*; their scope is between two
+normal (unconfined) labels. Confined symbols may be labels or equates. It is illegal
+to make a confined symbol global (with the ".globl" directive, a double colon, or a
+double equals). Only unconfined labels delimit a confined symbol's scope; equates
+(of any kind) do not count. For example, all symbols are unique and have unique
+values in the following:
+
+ ::
+
+ zero:: subq.w $1,d1
+ bmi.s .ret
+ .loop: clr.w (a0)+
+ dbra d0,.loop
+ .ret: rta
+ FF:: subq.w #1,d1
+ bmi.s .99
+ .loop: move.w -1,(a0)+
+ dbra d0,.loop
+ .99: its
+
+Confined symbols are useful since the programmer has to be much less inventive
+about finding small, unique names that also have meaning.
+
+It is legal to define symbols that have the same names as processor mnemonics
+(such as "**move**" or "**rts**") or assembler directives (such as "**.even**"). Indeed, one
+should be careful to avoid typographical errors, such as this classic (in 6502 mode):
+
+ ::
+
+ .6502
+ .org = $8000
+
+
+which equates a confined symbol to a hexadecimal value, rather than setting the
+location counter, which the .org directive does (without the equals sign).
+
+`Keywords`_
+'''''''''''
+The following names, in all combinations of uppercase and lowercase, are keywords
+and may not be used as symbols (e.g. labels, equates, or the names of macros):
+
+ ::
+
+ equ set reg
+ sr ccr pc sp ssp usp
+ dO di d2 d3 d4 d5 d6 d7
+ a0 al a2 a3 a4 a5 a6 aT
+ r0 ri r2 r3 r4 r5 r6 r7
+ r8 r9 r10 1'11 r12 rl3 ri4 ri5
+
+`Constants`_
+''''''''''''
+Numbers may be decimal, hexadecimal, octal, binary or concatenated ASCII. The
+default radix is decimal, and it may not be changed. Decimal numbers are specified
+with a string of digits (**0-9**). Hexadecimal numbers are specified with a leading
+dollar sign (**$**) followed by a string of digits and uppercase or lowercase letters (**A-F
+a-f**). Octal numbers are specified with a leading at-sign (**@**) followed by a string
+of octal digits (**0-7**). Binary numbers are specified with a leading percent sign
+(**%**) followed by a string of binary digits (**0-1**). Concatenated ASCII constants are
+specified by enclosing from one to four characters in single or double quotes. For
+example:
+
+ ::
+
+ 1234 *decimal*
+ $1234 *hexadecimal*
+ @777 *octal*
+ %10111 *binary*
+ "z" *ASCII*
+ 'frog' *ASCII*
+
+Negative numbers Are specified with a unary minus (**-**). For example:
+
+ ::
+
+ -5678 -@334 -$4e71
+ -%11011 -'z' -"WIND"
+
+`Strings`_
+''''''''''
+Strings are contained between double (") or single ( ') quote marks. Strings may
+contain non-printable characters by specifying "backslash" escapes, similar to the
+ones used in the C programming language. MADMAC will generate a warning if a
+backslash is followed by a character not appearing below:
+
+ ::
+
+ \\ $5c backslash
+ \n $0a line-feed (newline)
+ \b $08 backspace
+ \t $09 tab
+ \r $0c1 carriage-return
+ \f $0c form-feed
+ \e $1b escape
+ \' $27 single-quote
+ \" $22 double-quote
+
+It is possible for strings (but not symbols) to contain characters with their high
+bits set (i.e. character codes 128...255).
+
+You should be aware that backslash characters are popular in GEMDOS path
+names, and that you may have to escape backslash characters in your existing source
+code. For example, to get the file "'c:\auto\andi.s'" you would specify the string
+"`c:\\auto\\andi.s`".
+
+`Register Lists`_
+'''''''''''''''''
+Register lists are special forms used with the **movem** mnemonic and the **.reg**
+directive. They are 16-bit values, with bits 0 through 15 corresponding to registers
+**D0** through **A7**. A register list consists of a series of register names or register
+ranges seperated by slashes. A register range consists of two register names, Rm
+and Rn,m<n, seperated by a dash. For example:
+
+ ::
+
+ register list value
+ ------------- -----
+ 40-d7/a0-a7 $FFFF
+ d2-d7/a0/a3-a6 $39FC
+ dO/d1/a0-a3/d7/a6-a7 $CF83
+ d0 $0001
+ r0-r16 $FFFF
+
+Register lists and register equates may be used in conjunction with the movem
+mnemonic, as in this example:
+
+ ::
+
+ temps reg d0-d2/a0-a2 ; temp registers
+ keeps reg d3-d7/d3-a6 ; registers to preserve
+ allregs reg d0-d7/a0-a7 ; all registers
+ movem.l #temps, -(sp) ; these two lines ...
+ aovea.l dO -d2/a0 -a2, -(sp) ; are identical
+ movea.l #keeps, -(sp) ; save "keep" registers
+ noven.1 (sp)+,#keeps ; restore "keep" registers
+
+
+`Expressions`_
+==============
+`Order of Evaluation`_
+''''''''''''''''''''''
+All values are computed with 32-bit 2's complement arithmetic. For boolean operations
+(such as if or **assert**) zero is considered false, and non-zero is considered
+true.
+
+ **Expressions are evaluated strictly left-to-right, with no
+ regard for operator precedence.**
+
+Thus the expression "1+2*3" evaluates to 9, not 7. However, precedence may be
+forced with parenthesis (**()**) or square-brackets (**[]**).
+
+`Types`_
+'''''''''
+Expressions belong to one of three classes: undefined, absolute or relocatable. An
+expression is undefined if it involves an undefined symbol (e.g. an undeclared sym-
+bol, or a forward reference). An expression is absolute if its value will not change
+when the program is relocated (for instance, the number 0, all labels declared in
+an abs section, and all Atari ST hardware register locations are absolute values).
+An expression is relocatable if it involves exactly one symbol that is contained in a
+text, data or BSS section.
+
+Only absolute values may be used with operators other than addition (+) or
+subtraction (-). It is illegal, for instance, to multiply or divide by a relocatable or
+undefined value. Subtracting a relocatable value from another relocatable value in
+the same section results in an absolute value (the distance between them, positive
+or negative). Adding (or subtracting) an absolute value to or from a relocatable
+value yeilds a relocatable value (an offset from the relocatable address).
+
+It is important to realize that relocatable values belong to the sections they
+are defined in (e.g. text, data or BSS), and it is not permissible to mix and match
+sections. For example, in this code:
+
+ ::
+
+ linel: dc.l line2, linel+8
+ line2: dc.l linel, line2-8
+ line3: dc.l line2-linel, 8
+ error: dc.l linel+line2, line2 >> 1, line3/4
+
+Line 1 deposits two longwords that point to line 2. Line 2 deposits two longwords
+that point to line 1. Line 3 deposits two longwords that have the absolute value
+eight. The fourth line will result in an assembly error, since the expressions (re-
+spectively) attempt to add two relocatable values, shift a relocatable value right by
+one, and divide a relocatable value by four.
+
+The pseudo-symbol "*****" (star) has the value that the current section's location
+counter had at the beginning of the current source line. For example, these two
+statements deposit three pointers to the label "**bar**":
+
+ ::
+
+ too: dc.l *+4
+ bar: dc.l *, *
+
+Similarly, the pseudo-symbol "**$**" has the value that the current section's location
+counter has, and it is kept up to date as the assembler deposits information
+"across" a line of source code. For example, these two statements deposit four
+pointers to the label "zip":
+
+ ::
+
+ zip: dc.l $+8, $+4
+ zop: dc.l $, $-4
+
+`Unary Operators`_
+''''''''''''''''''
+
+================================ ====================================
+Operator Description
+================================ ====================================
+**-** Unary minus (2's complement).
+**!** Logical (boolean) NOT.
+**~** Tilde: bitwise not (l's complement).
+**^^defined** *symbol* True if symbol has a value.
+**^^referenced** *symbol* True if symbol has been referenced.
+**^^streq** *stringl*,*string2* True if the strings are equal.
+**^^macdef** *macroName* True if the macro is defined.
+================================ ====================================
+
+ o The boolean operators generate the value 1 if the expression is true, and 0 if
+ it is not.
+
+ o A symbol is referenced if it is involved in an expression. A symbol may have
+ any combination of attributes: undefined and unreferenced, defined and unref-
+ erenced (i.e. declared but never used), undefined and referenced (in the case
+ of a forward or external reference), or defined and referenced.
+
+
+
+`Binary Operators`_
+'''''''''''''''''''
+
+----------- ----------------------------------------------
+Operator Description
+----------- ----------------------------------------------
++ - * / The usual arithmetic operators.
+% Modulo.
+& | ^ Bit-wise **AND**, **OR** and **Exclusive-OR**.
+<< >> Bit-wise shift left and shift right.
+< <= >= > Boolean magnitude comparisons.
+= Boolean equality.
+<> != Boolean inequality.
+----------- ----------------------------------------------
+
+ o All binary operators have the same precedence: expressions are evaluated
+ strictly left to right.
+
+ o Division or modulo by zero yields an assembly error
+
+ o The "<>" and "!=" operators are synonyms.
+
+ o Note that the modulo operator (%) is also used to introduce binary constants
+ (see: `Constants`_). A percent sign should be followed by at least one space if
+ it is meant to be a modulo operator, and is followed by a '0' or '1'.
+
+`Special Forms`_
+''''''''''''''''
+
+============ =========================================
+Special Form Description
+============ =========================================
+**^^date** The current system date (Gemdos format).
+**^^time** The current system time (Gemdos format).
+============ =========================================
+
+ o The "**^^date**" special form expands to the current system date, in Gemdos
+ format. The format is a 16-bit word with bits 0 ...4 indicating the day of the
+ month (1...31), bits 5...8 indicating the month (1...12), and bits 9...15
+ indicating the year since 1980, in the range 0...119.
+
+ o The "**^^time**" special form expands to the current system time, in Gemdos
+ format. The format is a 16-bit word with bits 0...4 indicating the current
+ second divided by 2, bits 5...10 indicating the current minute 0...59. and
+ bits 11...15 indicating the current hour 0...23.
+
+`Example Expressions`_
+''''''''''''''''''''''
+
+ ::
+
+ line address contents source code
+ ---- ------- -------- -------------------------------
+ 1 00000000 4480 lab1: neg.l d0
+ 2 00000002 427900000000 lab2: clr.w lab1
+ 3 =00000064 equ1 = 100
+ 4 =00000096 equ2 = equ1 + 50
+ 5 00000008 00000064 dc.l lab1 + equ1
+ 6 0000000C 7FFFFFE6 dc.l (equl + ~equ2) >> 1
+ 7 00000010 0001 dc.w ^^defined equl
+ 8 00000012 0000 dc.w ^^referenced lab2
+ 9 00000014 00000002 dc.l lab2
+ 10 00000018 0001 dc.w ^^referenced lab2
+ 11 0000001A 0001 dc.w lab1 = (lab2 - 6)
+
+Lines 1 through four here are used to set up the rest of the example. Line 5 deposits
+a relocatable pointer to the location 100 bytes beyond the label "**lab1**". Line 6 is
+a nonsensical expression that uses the and right-shift operators. Line 7 deposits
+a word of 1 because the symbol "**equ1**" is defined (in line 3).
+
+Line 8 deposits a word of 0 because the symbol "**lab2**", defined in line 2, has
+not been referenced. But the expression in line 9 references the symbol "**lab2**", so
+line 10 (which is a copy of line-8) deposits a word of 1. Finally, line 11 deposits a
+word of 1 because the Boolean equality operator evaluates to true.
+
+The operators "**^^defined**" and "**^^referenced**" are particularly useful in
+conditional assembly. For instance, it is possible to automatically include debugging
+code if the debugging code is referenced, as in:
+
+ ::
+
+ lea string,a0 ; AO -> message
+ jsr debug ; print a message
+ its ; and return
+ string: dc.b "Help me, Spock!",0 ; (the message)
+ .
+ .
+ .
+ .iif ^^defined debug, .include "debug.s"
+
+The **jsr** statement references the symbol debug. Near the end of the source file, the
+"**.iif**' statement includes the file "**debug.s**" if the symbol debug was referenced.
+
+In production code, presumably all references to the debug symbol will be removed,
+and the debug source file will not be included. (We could have as easily made the
+symbol **debug** external, instead of including another source file).
+
+
+`Directives`_
+=============
+
+Assembler directives may be any mix of upper- or lowercase. The leading periods
+are optional, though they are shown here and their use is encouraged. Directives
+may be preceeded by a label; the label is defined before the directive is executed.
+Some directives accept size suffixes (**.b**, **.s**, **.w** or **.1**); the default is word (**.w**) if no
+size is specified. The **.s** suffix is identical to **.b**. Directives relating to the 6502 are
+described in the chapter on `6502 Support`_.
+
+
+
+**.even**
+ If the location counter for the current section is odd, make it even by adding
+ one to it. In text and data sections a zero byte is deposited if necessary.
+**.assert** *expression* [,\ *expression*...]
+ Assert that the conditions are true (non-zero). If any of the comma-seperated
+ expressions evaluates to zero an assembler warning is issued. For example:
+
+ ::
+
+ .assert *-start = $76
+ .assert stacksize >= $400
+
+**.bss**
+
+**.data**
+
+**.text**
+ Switch to the BSS, data or text segments. Instructions and data may not
+ be assembled into the BSS-segment, but symbols may be defined and storage
+ may be reserved with the **.ds** directive. Each assembly starts out in the text
+ segment.
+**.abs** [*location*]
+ Start an absolute section, beginning with the specified location (or zero, if
+ no location is specified). An absolute section is much like BSS, except that
+ locations declared with .ds are based absolute. This directive is useful for
+ declaring structures or hardware locations.
+ For example, the following equates:
+
+ ::
+
+ VPLANES = 0
+ VWRAP = 2
+ CONTRL = 4
+ INTIN = 8
+ PTSIN = 12
+
+ could be as easily defined as:
+
+ ::
+
+ .abs
+ VPLANES: ds.w 1
+ VWRAP: ds.w 1
+ CONTRL: ds.l 1
+ INTIE: ds.l 1
+ PTSIN: ds.l 1
+
+**.comm** *symbol*, *expression*
+ Specifies a label and the size of a common region. The label is made global,
+ thus confined symbols cannot be made common. The linker groups all com-
+ mon regions of the same name; the largest size determines the real size of the
+ common region when the file is linked.
+
+**.dc**\ [.\ *size*] *expression* [, *expression*...]
+ Deposit initialized storage in the current section. If the specified size is word
+ or long, the assembler will execute a .even before depositing data. If the size
+ is .b, then strings that are not part of arithmetic expressions are deposited
+ byte-by-byte. If no size is specified, the default is .w. This directive cannot be
+ used in the BSS section.
+
+**.dcb**\ [.\ *size*] *expression1*, *expression2*
+ Generate an initialized block of *expression1* bytes, words or longwords of the
+ value *expression2*. If the specified size is word or long, the assembler will
+ execute .even before generating data. If no size is specified, the default is **.w**.
+ This directive cannot be used in the BSS section.
+
+**.ds**\ [.\ *size*] *expression*
+ Reserve space in the current segment for the appropriate number of bytes,
+ words or longwords. If no size is specified, the default size is .w. If the size
+ is word or long, the assembler will execute .even before reserving space. This
+ directive can only be used in the BSS or ABS sections (in text or data, use
+ .dcb to reserve large chunks of initialized storage.)
+
+**.init**\ [.\ *size*] [#\ *expression*,]\ *expression*\ [.\ *size*] [,...]
+ Generalized initialization directive. The size specified on the directive becomes
+ the default size for the rest of the line. (The "default" default size is **.w**.) A
+ comma-seperated list of expressions follows the directive; an expression may be
+ followed by a size to override the default size. An expression may be preceeded
+ by a sharp sign, an expression and a comma, which specifies a repeat count to
+ be applied to the next expression. For example:
+
+ ::
+
+ .init.l -1, 0.w, #16,'z'.b, #3,0, 11.b
+
+ will deposit a longword of -1, a word of zero, sixteen bytes of lower-case 'z',
+ three longwords of zero, and a byte of 11.
+
+ No auto-alignment is performed within the line, but a **.even** is done once
+ (before the first value is deposited) if the default size is word or long.
+
+**.cargs** [#\ *expression*,] *symbol*\ [.\ *size*] [, *symbol*\ [.\ *size*].. .]
+ Compute stack offsets to C (and other language) arguments. Each symbol is
+ assigned an absolute value (like equ) which starts at expression and increases
+ by the size of each symbol, for each symbol. If the expression is not supplied,
+ the default starting value is 4. For example:
+
+ ::
+
+ .cargs #8, .fileliams.1, .openMode, .butPointer.l
+
+ could be used to declare offsets from A6 to a pointer to a filename, a word
+ containing an open mode, and a pointer to a buffer. (Note that the symbols
+ used here are confined). Another example, a C-style "string-length" function,
+ could be written as:
+
+ ::
+
+ _strlen:: .cargs .string ; declare arg
+ move.l .string(sp),a0 ; a0 -> string
+ moveq #-1,d0 ; initial size = -1
+ .1: addq.1 #1,d0 ; bump size
+ tst.b (a0)+ ; at end of string?
+ bne .1 ; (no -- try again)
+ rts ; return string length
+
+**.end**
+ End the assembly. In an include file, end the include file and resume assembling
+ the superior file. This statement is not required, nor are warning messages
+ generated if it is missing at the end of a file. This directive may be used inside
+ conditional assembly, macros or **.rept** blocks.
+
+**.if** *expression*
+
+**.else**
+
+**.endif**
+
+ Start a block of conditional assembly. If the expression is true (non-zero) then
+ assemble the statements between the .if and the matching **.endif** or **.else**.
+ If the expression is false, ignore the statements unless a matching .else is
+ encountered. Conditional assembly may be nested to any depth.
+
+ It is possible to exit a conditional assembly block early from within an include
+ file (with **end**) or a macro (with **endm**).
+
+**.iif** *expression*, *statement*
+
+ Immediate version of **.if**. If the expression is true (non-zero) then the state-
+ ment, which may be an instruction, a directive or a macro, is executed. If
+ the expression is false, the statement is ignored. No **.endif** is required. For
+ example:
+
+ ::
+
+ .iif age < 21, canDrink = 0
+ .iif weight > 500, dangerFlag = 1
+ .iif !(^^defined DEBUG), .include dbsrc
+
+**.macro** *name* [*formal*, *formal*,...]
+
+**.endm**
+
+**.exitm**
+ Define a macro called name with the specified formal arguments. The macro
+ definition is terminated with a **.endm** statement. A macro may be exited early
+ with the .exitm directive. See the chapter on `Macros`_ for more information.
+
+**.undefmac** *macroName* [, *macroName*...]
+ Remove the macro-definition for the specified macro names. If reference is
+ made to a macro that is not defined, no error message is printed and the name
+ is ignored.
+
+**.rept** *expression*
+
+**.endr**
+ The statements between the **.rept** and **.endr** directives will be repeated *expression*
+ times. If the expression is zero or negative, no statements will be
+ assembled. No label may appear on a line containing either of these directives.
+
+**.globl** *symbol* [, *symbol*...]
+
+**.extern** *symbol* [, *symbol*...]
+ Each symbol is made global. None of the symbols may be confined symbols
+ (those starting with a period). If the symbol is defined in the assembly, the
+ symbol is exported in the object file. If the symbol is undefined at the end
+ of the assembly, and it was referenced (i.e. used in an expression), then the
+ symbol value is imported as an external reference that must be resolved by the
+ linker. The **.extern** directive is merely a synonym for **.globl**.
+
+**.include** "*file*"
+ Include a file. If the filename is not enclosed in quotes, then a default extension
+ of "**.s**" is applied to it. If the filename is quoted, then the name is not changed
+ in any way.
+
+ Note: If the filename is not a valid symbol, then the assembler will generate an
+ error message. You should enclose filenames such as "**atari.s**" in quotes,
+ because such names are not symbols.
+
+ If the include file cannot be found in the current directory, then the direc-
+ tory search path, as specified by -i on the commandline, or' by the 'MACPATH'
+ enviroment string, is traversed.
+
+**.eject**
+ Issue a page eject in the listing file.
+
+**.title** "*string*"
+
+**.subttl** [-] "*string*"
+ Set the title or subtitle on the listing page. The title should be specified on
+ the the first line of the source program in order to take effect on the first page.
+ The second and subsequent uses of **.title** will cause page ejects. The second
+ and subsequent uses of .subttl will cause page ejects unless the subtitle string
+ is preceeded by a dash (-).
+
+**.list**
+
+**.nlist**
+ Enable or disable source code listing. These directives increment and decrement
+ an internal counter, so they may be appropriately nested. They have no effect
+ if the **-l** switch is not specified on the commandline.
+
+**.goto** *label*
+ This directive provides unstructured flow of control within a macro definition.
+ It will transfer control to the line of the macro containing the specified goto
+ label. A goto label is a symbol preceeded by a colon that appears in the first
+ column of a source line within a macro definition:
+
+ : *label*
+
+ where the label itself can be any valid symbol name, followed immediately by
+ whitespace and a valid source line (or end of line). The colon **must** appear in
+ the first column.
+
+ The goto-label is removed from the source line prior to macro expansion -
+ to all intents and purposes the label is invisible except to the .goto directive
+ Macro expansion does not take place within the label.
+
+ For example, here is a silly way to count from 1 to 10 without using **.rept**:
+
+ ::
+
+ .macro Count
+ count set 1
+ :loop dc.w count
+ count set count + 1
+ iif count <= 10, goto loop
+ .endm
+
+`68000 Mnemonics`_
+==================
+
+`Mnemonics`_
+''''''''''''
+All of the standard Motorola 68000 mnemonics and addressing modes are supported;
+you should refer to **The Motorola M68000 Programmer's Reference Manual**
+for a description of the instruction set and the allowable addressing modes for each
+instruction. With one major exception (forward branches) the assembler performs
+all the reasonable optimizations of instructions to their short or address register
+forms.
+
+Register names may be in upper or lower case. The alternate forms ``R0`` through
+``R15`` may be used to specify ``D0`` through ``A7``. All register names are keywords, and
+may not be used as labels or symbols. None of the 68010 or 68020 register names
+are keywords (but they may become keywords in the future).
+
+`Addressing Modes`_
+'''''''''''''''''''
+
+===================================== ===========================================
+Assembler Syntax Description
+===================================== ===========================================
+*Dn* Data register direct
+*An* Address register direct
+(*An*) Address register indirect
+(*An*)+ Address register indirect postincrement
+-(*An*) Address register indirect predecrement
+*disp*\ (*An*) Address register indirect with displacement
+*bdisp*\ (*An*, *Xi*\ [.\ *size*]) Address register indirect indexed
+*abs*.w Absolute short
+*abs* Absolute (long or short)
+*abs*.l Forced absolute long
+*disp*\ (PC) Program counter with displacement
+*bdisp*\ (PC, *Xi*\ ) Program counter indexed
+#\ *imm* Immediate
+===================================== ===========================================
+
+`Branches`_
+'''''''''''
+Since MADMAC is a one pass assembler, forward branches cannot be automatically
+optimized to their short form. Instead, unsized forward branches are assumed to
+be long. Backward branches are always optimized to the short form if possible.
+
+A table that lists "extra" branch mnemonics (common synonyms for the Motorola
+defined mnemonics) appears below.
+
+`Linker Constraints`_
+'''''''''''''''''''''
+It is not possible to make an external reference that will fix up a byte. For example:
+
+ ::
+
+ extern frog
+ move.l frog(pc,d0),d1
+
+is illegal (and generates an assembly error) when frog is external, because the
+displacement occupies a byte field in the 68000 offset word, which the object file
+cannot represent.
+
+`Branch Synonyms`_
+''''''''''''''''''
+============== ========
+Alternate name Becomes:
+============== ========
+bhs bcc
+blo bcs
+bse, bs beq
+bns bne
+dblo dbcs
+dbse dbeq
+dbra dbf
+dbhs dbhi
+dbns dbne
+============== ========
+
+`Optimizations and Translations`_
+'''''''''''''''''''''''''''''''''
+The assembler provides "creature comforts" when it processes 68000 mnemonics:
+
+ o **CLR.x An** will really generate **SUB.x An,An**.
+
+ o **ADD**, **SUB** and **CMP** with an address register will really generate **ADDA**,
+ **SUBA** and **CMPA**.
+
+ o The **ADD**, **AND**, **CMP**, **EOR**, **OR and **SUB** mnemonics with immediate
+ first operands will generate the "I" forms of their instructions (**ADDI**, etc.) if
+ the second operand is not register direct.
+
+ o All shift instructions with no count value assume a count of one.
+
+ o **MOVE.L** is optimized to **MOVEQ** if the immediate operand is defined and
+ in the range -128...127. However, **ADD** and **SUB** are never translated to
+ their quick forms; **ADDQ** and **SUBQ** must be explicit.
+
+`Macros`_
+=========
+`Macro declaration`_
+''''''''''''''''''''
+A macro definition is a series of statements of the form:
+ ::
+
+ .macro name [ formal-arg, ...]
+ .
+ .
+ .
+ statements making up the macro body
+ .
+ .
+ .
+ .endm
+
+The name of the macro may be any valid symbol that is not also a 68000 instruction
+or an assembler directive. (The name may begin with a period - macros cannot
+be made confined the way labels or equated symbols can be). The formal argument
+list is optional; it is specified with a comma-seperated list of valid symbol names.
+Note that there is no comma between the name of the macro and the name of the
+first formal argument.
+
+A macro body begins on the line after the **.macro** directive. All instructions
+and directives, except other macro definitions, are legal inside the body.
+
+The macro ends with the **.endm** statement. If a label appears on the line with
+this directive, the label is ignored and a warning is generated.
+
+`Parameter Substitution`_
+'''''''''''''''''''''''''
+Within the body, formal parameters may be expanded with the special forms:
+ ::
+
+ \name
+ \{name}
+
+The second form (enclosed in braces) can be used in situations where the characters
+following the formal parameter name are valid symbol continuation characters. This
+is usually used to force concatentation, as in:
+
+ ::
+
+ \{frog}star
+ \(godzilla}vs\{reagan}
+
+The formal parameter name is terminated with a character that is not valid in
+a symbol (e.g. whitespace or puncuation); optionally, the name may be enclosed in
+curly-braces. The names must be symbols appearing on the formal argument list,
+or a single decimal digit (``\1`` corresponds to the first argument, ``\2`` to the second,
+``\9`` to the ninth, and ``\0`` to the tenth). It is possible for a macro to have more than
+ten formal arguments, but arguments 11 and on must be referenced by name, not
+by number.
+
+ Other special forms are:
+
+============ ================================================
+Special Form Description
+============ ================================================
+``\\`` a single "\",
+``\~`` a unique label of the form "Mn"
+``\#`` the number of arguments actually specified
+``\!`` the "dot-size" specified on the macro invocation
+``\?name`` conditional expansion
+``\?{name}`` conditional expansion
+============ ================================================
+
+The last two forms are identical: if the argument is specified and is non-empty, the
+form expands to a "1", otherwise (if the argument is missing or empty) the form
+expands to a "0".
+
+The form "``\!``" expands to the "dot-size" that was specified when the macro
+was invoked. This can be used to write macros that behave differently depending
+on the size suffix they are given, as in this macro which provides a synonym for the
+"``dc``" directive:
+
+ ::
+
+ .macro deposit value
+ dc\! \value
+ .endm
+ deposit.b 1 ; byte of 1
+ deposit.w 2 ; word of 2
+ deposit.l 3 ; longvord of 3
+ deposit 4 ; word of 4 (no explicit size)
+
+`Macro Invocation`_
+'''''''''''''''''''
+A previously-defined macro is called when its name appears in the operation field of
+a statement. Arguments may be specified following the macro name; each argument
+is seperated by a comma. Arguments may be empty. Arguments are stored for
+substitution in the macro body in the following manner:
+
+ o Numbers are converted to hexadecimal.
+
+ o All spaces outside strings are removed.
+
+ o Keywords (such as register names, dot sizes and "^^" operators) are converted
+ to lowercase.
+
+ o Strings are enclosed in double-quote marks (").
+
+For example, a hypothetical call to the macro "``mymacro``", of the form:
+ ``mymacro A0, , 'Zorch' / 32, "^^DEFINED foo, , , tick tock``
+
+will result in the translations:
+
+======== ================= =================================================
+Argument Expansion Comment
+======== ================= =================================================
+``\1`` ``a0`` "``A0``" converted to lower-case
+``\2`` empty
+``\3`` ``"Zorch"/$20`` "``Zorch``" in double-quotes, 32 in hexadecimal
+``\4`` ``^^defined foo`` "``^^DEFINED``" converted to lower-case
+``\5`` empty
+``\6`` empty
+``\7`` ``ticktock`` spaces removed (note concatenation)
+======== ================= =================================================
+
+The **.exitm** directive will cause an immediate exit from a macro body. Thus
+the macro definition:
+
+ ::
+
+ .macro foo source
+ .iif !\?source, .exitm ; exit if source is empty
+ move \source,d0 ; otherwise, deposit source
+ .endm
+
+will not generate the move instruction if the argument **"source"** is missing from
+the macro invocation.
+
+The **.end**, **.endif** and **.exitm** directives all pop-out of their include levels
+appropriately. That is, if a macro performs a **.include** to include a source file, an
+executed **.exitm** directive within the include-file will pop out of both the include-file
+and the macro.
+
+Macros may be recursive or mutually recursive to any level, subject only to
+the availability of memory. When writing recursive macros, take care in the coding
+of the termination condition(s). A macro that repeatedly calls itself will cause the
+assembler to exhaust its memory and abort the assembly.
+
+
+`Example Macros`_
+'''''''''''''''''
+The Gemdos macro is used to make file system calls. It has two parameters, a
+function number and the number of bytes to clean off the stack after the call. The
+macro pushes the function number onto the stack and does the trap to the file
+system. After the trap returns, conditional assembly is used to choose an addq or
+an **add.w** to remove the arguments that were pushed.
+
+ ::
+
+ .macro Gemdos trpno, clean
+ move.w #\trpno,-(sp) ; push trap number
+ trap #1 ; do GEMDOS trap
+ .if \clean <= 8 ;
+ addq #\clean,sp ; clean-up up to 8 bytes
+ .else ;
+ add.w #\clean,sp ; clean-up more than 8 bytes
+ .endif ;
+ .endm
+
+The Fopen macro is supplied two arguments; the address of a filename, and
+the open mode. Note that plain move instructions are used, and that the caller of
+the macro must supply an appropriate addressing mode (e.g. immediate) for each
+argument.
+
+ ::
+
+ .macro Fopen file, mode
+ movs.w \mode,-(sp) ;push open mode
+ move.1 \file,-(sp) ;push address of tile name
+ Gemdos $3d,8 ;do the GEMDOS call
+ .endm
+
+The **String** macro is used to allocate storage for a string, and to place the
+string's address somewhere. The first argument should be a string or other expres-
+sion acceptable in a dc.b directive. The second argument is optional; it specifies
+where the address of the string should be placed. If the second argument is omitted,
+the string's address is pushed onto the stack. The string data itself is kept in the
+data segment.
+
+ ::
+
+ .macro String str,loc
+ .if \?loc ; if loc is defined
+ move.l #.\~,\loc ; put the string's address there
+ .else ; otherwise
+ pea .\~ ; push the string's address
+ .endif ;
+ .data ; put the string data
+ .\~: dc.b \str,0 ; in the data segment
+ .text ; and switch back to the text segment
+ .endm
+
+The construction "``.\~``" will expand to a label of the form "``.M``\ *n*" (where *n* is
+a unique number for every macro invocation), which is used to tag the location of
+the string. The label should be confined because the macro may be used along with
+other confined symbols.
+
+Unique symbol generation plays an important part in the art of writing fine
+macros. For instance, if we needed three unique symbols, we might write "``.a\~``",
+"``.b\~``" and "``.c\~``".
+
+`Repeat Blocks`_
+''''''''''''''''
+Repeat-blocks provide a simple iteration capability. A repeat block allows a range
+of statements to be repeated a specified number of times. For instance, to generate
+a table consisting of the numbers 255 through 0 (counting backwards) you could
+write:
+
+ ::
+
+ .count set 255 ; initialize counter
+ .rept 256 ; repeat 256 times:
+ dc.b .count ; deposit counter
+ .count set .count - 1 ; and decrement it
+ .endr ; (end of repeat block)
+
+Repeat blocks can also be used to duplicate identical pieces of code (which are
+common in bitmap-graphics routines). For example:
+
+ ::
+
+ .rept 16 ; clear 16 words
+ clr.w (a0)+ ; starting at AO
+ .endr ;
+
+`6502 Support`_
+===============
+MADMAC will generate code for the Motorola 6502 microprocessor. This chapter
+describes extra addressing modes and directives used to support the 6502.
+
+As the 6502 object code is not linkable (currently there is no linker) external
+references may not be made. (Nevertheless, MADMAC may reasonably be used for
+large assemblies because of its blinding speed.)
+
+`6502 Addressing Modes`_
+''''''''''''''''''''''''
+All standard 6502 addressing modes are supported, with the exception of the
+accumulator addressing form, which must be omitted (e.g. "ror a" becomes "ror").
+Five extra modes, synonyms for existing ones, are included for compatibility with
+the Atari Coinop assembler.
+
+============== ========================================
+*empty* implied or accumulator (e.g. tsx or ror)
+*expr* absolute or zeropage
+#\ *expr* immediate
+(*expr*,x) indirect X
+(*expr*),y indirect Y
+(*expr*) indirect
+*expr*,x indexed X
+*expr*,y indexed Y
+@\ *expr*\ (x) indirect X
+@\ *expr*\ (y) indirect Y
+@expr indirect
+x,*expr* indexed X
+y,*expr* indexed Y
+============== ========================================
+
+While MADMAC lacks "high" and "low" operators, high bytes of words may
+be extracted with the shift (``>>``) or divide (``/``) operators, and low bytes may be
+extracted with the bitwise AND (``&``) operator.
+
+`6502 Directives`_
+''''''''''''''''''
+**.6502**
+ This directive enters the 6502 section. The location counter is undefined, and
+ must be set with ".org" before any code can be generated.
+
+ The "``dc.w``" directive will produce 6502-format words (low byte first). The
+ 68000's reserved keywords (``d0-d7/a0-a7/ssp/usp`` and so on) remain reserved
+ (and thus unusable) while in the 6502 section. The directives **globl**, **dc.l**,
+ **dcb.l**, **text**, **data**, **bss**, **abs**, **even** and **comm** are illegal in the 6502 section.
+ It is permitted, though probably not useful, to generate both 6502 and 68000
+ code in the same object file.
+**.68000**
+ This directive leaves the 6502 segment and returns to the 68000's text segment.
+ 68000 instructions may be assembled as normal.
+**.org** *location*
+ This directive is only legal in the 6502 section. It sets the value of the location
+ counter (or **pc**) to location, an expression that must be defined, absolute, and
+ less than $10000.
+
+ WARNING
+
+ It is possible to assemble "beyond" the microprocessor's 64K address space, but
+ attempting to do so will probably screw up the assembler. DO NOT attempt
+ to generate code like this:
+
+ ::
+
+ .org $fffe
+ nop
+ nop
+ nop
+
+ the third NOP in this example, at location $10000, may cause the assembler
+ to crash or exhibit spectacular schizophrenia. In any case, MADMAC will give
+ no warning before flaking out.
+
+`6502 Object Code Format`_
+''''''''''''''''''''''''''
+This is a little bit of a kludge. An object file consists of a page map, followed by
+one or more page images, followed by a normal Alcyon 68000 object file. If the page
+map is all zero, it is not written.
+
+The page map contains a byte for each of the 256 256-byte pages in the 6502's
+64K address space. The byte is zero (``$00``) if the page contained only zero bytes, or
+one (``$01``) if the page contained any non-zero bytes. If a page is flagged with a one,
+then it is written (in order) following the page map.
+
+The following code:
+
+ ::
+
+ .6502
+ .org $8000
+ .dc.b 1
+ .org $8100
+ .dc.b 1
+ .org $8300
+ .dc.b 1
+ .end
+
+will generate a page map that looks (to a programmer) something like:
+
+ ::
+
+ <80 bytes of zero>
+ 01 01 00 01
+ <$7c more bytes of zero, for $100 total>
+ <image of page $80>
+ <image of page $81>
+ <image of page $83>
+
+Following the last page image is an Alcyon-format object file, starting with
+the magic number ``$601a``. It may contain 68000 code (although that is probably
+useless), but the symbol table is valid and available for debugging purposes. 6502
+symbols will be absolute (not in text, data or bss).
+
+`Error Messages`_
+=================
+
+`When Things Go Wrong`_
+'''''''''''''''''''''''
+Most of MADMAC's error messages are self-explanatory. They fall into four classes:
+warnings about situations that you (or the assembler) may not be happy about,
+errors that cause the assembler to not generate object files, fatal errors that cause
+the assembler to abort immediately, and internal errors that should never happen.\ [3]_
+
+You can write editor macros (or sed or awk scripts) to parse the error messages
+MADMAC generates. When a message is printed, it is of the form:
+
+ "*filename*" , ``line`` *line-number*: *message*
+
+The first element, a filename enclosed in double quotes, indicates the file that generated
+the error. The filename is followed by a comma, the word "``line``", and a line
+number, and finally a colon and the text of the message. The filename "**(\*top\*)**"
+indicates that the assembler could not determine which file had the problem.
+
+The following sections list warnings, errors and fatal errors in alphabetical
+order, along with a short description of what may have caused the problem.
+
+`Warnings`_
+'''''''''''
+**bad backslash code in string**
+ You tried to follow a backslash in a string with a character that the assembler
+ didn't recognize. Remember that MADMAC uses a C-style escape system in
+ strings.
+**label ignored**
+ You specified a label before a macro, **rept** or **endm** directive. The assembler
+ is warning you that the label will not be defined in the assembly.
+**unoptimized short branch**
+ This warning is only generated if the -s switch is specified on the command
+ line. The message refers to a forward, unsized long branch that you could have
+ made short (.s).
+
+`Fatal Errors`_
+'''''''''''''''
+
+**cannot continue**
+ As a result of previous errors, the assembler cannot continue processing. The
+ assembly is aborted.
+**line too long as a result of macro expansion**
+ When a source line within a macro was expanded, the resultant line was too
+ long for MADMAC (longer than 200 characters or so).
+
+
+.. [3] If you come across an internal error, we would appreciate it if you would contact Atari Technical Support and let us know about the problem.
+
+**memory exhausted**
+ The assembler ran out of memory. You should (1) split up your source files
+ and assemble them seperately, or (2) if you have any ramdisks or RAM-resident
+ programs (like desk accessories) decrease their size so that the assembler has
+ more RAM to work with. As a rule of thumb, pure 68000 code will use up to
+ twice the number of bytes contained in the source files, whereas 6502 code will
+ use 64K of ram right away, plus the size of the source files. The assembler itself
+ uses about 80K bytes. Get out your calculator...
+**too many ENDMs**
+ The assembler ran across an **endm** directive when it wasn't expecting to see
+ one. The assembly is aborted. Check the nesting of your macro definitions -
+ you probably have an extra **endm**.
+
+
+`Errors`_
+'''''''''
+
+**.cargs syntax**
+ Syntax error in **.cargs** directive.
+**.comm symbol already defined**
+ You tried to ``.comm`` a symbol that was already defined.
+**.ds permitted only in BSS**
+ You tried to use ``.ds`` in the text or data section.
+**.init not permitted in BSS or ABS**
+ You tried to use ``.init`` in the BSS or ABS section.
+**.org permitted only in .6502 section**
+ You tried to use ``.org`` in a 68000 section.
+**Cannot create:** *filename*
+ The assembler could not create the indicated filename.
+**External quick reference**
+ You tried to make the immediate operand of a **moveq**, **subq** or **addq** instruction external.
+**PC-relative expr across sections**
+ You tried to make a PC-relative reference to a location contained in another
+ section.
+**[bwsl] must follow '.' in symbol**
+ You tried to follow a dot in a symbol name with something other than one of
+ the four characters 'B', 'W', 'S' or 'L'.
+**addressing mode syntax**
+ You made a syntax error in an addressing mode.
+**assert failure**
+ One of your **.assert** directives failed!
+**bad (section) expression**
+ You tried to mix and match sections in an expression
+**bad 6502 addressing mode**
+ The 6502 mnemonic will not work with the addressing mode you specified.
+**bad expression**
+ There's a syntax error in the expression you typed.
+**bad size specified**
+ You tried to use an inappropriate size suffix for the instruction. Check your
+ 68000 manual for allowable sizes.
+**bad size suffix**
+ You can't use .b (byte) mode with the **movem** instruction.
+**cannot .globl local symbol**
+ You tried to make a confined symbol global or common.
+**cannot initialize non-storage (BSS) section**
+ You tried to generate instructions (or data, with dc) in the BSS or ABS section.
+**cannot use '.b' with an address register**
+ You tried to use a byte-size suffix with an address register. The 68000 does not
+ perform byte-sized address register operations.
+**directive illegal in .6502 section**
+ You tried to use a 68000-oriented directive in the 6502 section.
+**divide by zero**
+ The expression you typed involves a division by zero.
+expression out of range
+ The expression you typed is out of range for its application.
+**external byte reference**
+ You tried to make a byte-sized reference to an external symbol, which the
+ object file format will not allow
+**external short branch**
+ You tried to make a short branch to an external symbol, which the linker cannot
+ handle.
+**extra (unexpected) text found after addressing mode**
+ MADMAC thought it was done processing a line, but it ran up against "extra"
+ stuff. Be sure that any comment on the line begins with a semicolon, and check
+ for dangling commas, etc.
+**forward or undefined .assert**
+ The expression you typed after a **.assert** directive had an undefined value.
+ Remember that MADMAC is one-pass.
+**hit EOF without finding matching .endif**
+ The assembler fell off the end of last input file without finding a **.endif** to
+ match an . it. You probably forgot a **.endif** somewhere.
+**illegal 6502 addressing mode**
+ The 6502 instruction you typed doesn't work with the addressing mode you
+ specified.
+**illegal absolute expression**
+ You can't use an absolute-valued expression here.
+**illegal bra.s with zero offset**
+ You can't do a short branch to the very next instruction (read your 68000
+ manual).
+**illegal byte-sized relative reference**
+ The object file format does not permit bytes contain relocatable values; you
+ tried to use a byte-sized relocatable expression in an immediate addressing
+ mode.
+**illegal character**
+ Your source file contains a character that MADMAC doesn't allow. (most
+ control characters fall into this category).
+**illegal initialization of section**
+ You tried to use .dc or .dcb in the BSS or ABS sections.
+**illegal relative address**
+ The relative address you specified is illegal because it belongs to a different
+ section.
+**illegal word relocatable (in .PRG mode)**
+ You can't have anything other than long relocatable values when you're gener-
+ ating a **.PRG** file.
+**inappropriate addressing mode**
+ The mnemonic you typed doesn't work with the addressing modes you specified.
+ Check your 68000 manual for allowable combinations.
+**invalid addressing mode**
+ The combination of addressing modes you picked for the **movem** instruction
+ are not implemented by the 68000. Check your 68000 reference manual for
+ details.
+**invalid symbol following ^^**
+ What followed the ^^ wasn't a valid symbol at all.
+**mis-nested .endr**
+ The assembler found a **.endr** directive when it wasn't prepared to find one.
+ Check your repeat-block nesting.
+**mismatched .else**
+ The assembler found a **.else** directive when it wasn't prepared to find one.
+ Check your conditional assembly nesting.
+**mismatched .endif**
+ The assembler found a **.endif** directive when it wasn't prepared to find one.
+ Check your conditional assembly nesting.
+
+**missing '='**
+
+**missing '}'**
+
+**missing argument name**
+
+**missing close parenthesis ')'**
+
+**missing close parenthesis ']'**
+
+**missing comma**
+
+**missing filename**
+
+**missing string**
+
+**missing symbol**
+
+**missing symbol or string**
+ The assembler expected to see a symbol/filename/string (etc...), but found
+ something else instead. In most cases the problem should be obvious.
+**misuse of '.', not allowed in symbols**
+ You tried to use a dot (.) in the middle of a symbol name.
+**mod (%) by zero**
+ The expression you typed involves a modulo by zero.
+**multiple formal argument definition**
+ The list of formal parameter names you supplied for a macro definition includes
+ two identical names.
+**multiple macro definition**
+ You tried to define a macro which already had a definition.
+**non-absolute byte reference**
+ You tried to make a byte reference to a relocatable value, which the object file
+ format does not allow.
+**non-absolute byte value**
+ You tried to dc.b or dcb.b a relocatable value. Byte relocatable values are
+ not permitted by the object file format.
+**register list order**
+ You tried to specify a register list like **D7-D0**, which is illegal. Remember
+ that the first register number must be less than or equal to the second register
+ number.
+**register list syntax**
+ You made an error in specifying a register list for a **.reg** directive or a **.movem**
+ instruction.
+**symbol list syntax**
+ You probably forgot a comma between the names of two symbols in a symbol
+ list, or you left a comma dangling on the end of the line.
+**syntax error**
+ This is a "catch-all" error.
+**undefined expression**
+ The expression has an undefined value because of a forward reference, or an
+ undefined or external symbol.
+**unimplemented addressing mode**
+ You tried to use 68020 "square-bracket" notation for a 68020 addressing mode.
+ MADMAC does not support 68020 addressing modes.
+**unimplemented directive**
+ You have found a directive that didn't appear in the documentation. It doesn't
+ work.
+**unimplemented mnemonic**
+ You've found an assembler for documentation) bug.
+**unknown symbol following ^^**
+ You followed a ^^ with something other than one of the names defined, ref-
+ erenced or streq.
+**unsupported 68020 addressing mode**
+ The assembler saw a 68020-type addressing mode. MADMAC does not assem-
+ ble code for the 68020 or 68010.
+**unterminated string**
+ You specified a string starting with a single or double quote, but forgot to type
+ the closing quote.
+**write error**
+ The assembler had a problem writing an object file. This is usually caused by
+ a full disk, or a bad sector on the media.
projects / rmac / commitdiff