EOY minor update.

[rmac] / direct.c

diff --git a/direct.c b/direct.c
index 0c8dfb5b0fba563a5081a800c4cf64df83bb57f1..b3f51f3c3b73356c638a0dc9b087cc20f67ab58d 100644 (file)
--- a/direct.c
+++ b/direct.c
@@ -1,7 +1,7 @@
 //
 // RMAC - Reboot's Macro Assembler for all Atari computers
 // DIRECT.C - Directive Handling
-// Copyright (C) 199x Landon Dyer, 2011-2019 Reboot and Friends
+// Copyright (C) 199x Landon Dyer, 2011-2020 Reboot and Friends
 // RMAC derived from MADMAC v1.07 Written by Landon Dyer, 1986
 // Source utilised with the kind permission of Landon Dyer
 //
@@ -51,6 +51,7 @@ int d_abs(void);
 int d_comm(void);
 int d_dc(WORD);
 int d_ds(WORD);
+int d_dsm(WORD);
 int d_dcb(WORD);
 int d_globl(void);
 int d_gpu(void);
@@ -153,6 +154,7 @@ int (*dirtab[])() = {
        d_nofpu,                        // 65 nofpu
        d_opt,                          // 66 .opt
        d_objproc,                      // 67 .objproc
+       d_dsm,                          // 68 .dsm
 };
 
 
@@ -1075,9 +1077,9 @@ int d_ds(WORD siz)
 
        // Check to see if the value being passed in is negative (who the hell does
        // that?--nobody does; it's the code gremlins, or rum, what does it)
-       // N.B.: Since 'eval' is of type uint32_t, if it goes negative, it will
+       // N.B.: Since 'eval' is of type uint64_t, if it goes negative, it will
        //       have its high bit set.
-       if (eval & 0x80000000)
+       if (eval & 0x8000000000000000)
                return error("negative sizes not allowed in DS");
 
        // In non-TDB section (BSS, ABS and M6502) just advance the location
@@ -1094,7 +1096,7 @@ int d_ds(WORD siz)
 
                just_bss = 1;                                   // No data deposited (8-bit CPU mode)
        }
-       else if (cursect == M56001P || cursect == M56001X || cursect == M56001Y || cursect == M56001L)
+       else if (cursect & M56KPXYL)
        {
                // Change segment instead of marking blanks.
                // Only mark segments we actually wrote something
@@ -1123,7 +1125,52 @@ int d_ds(WORD siz)
        }
 
        ErrorIfNotAtEOL();
-       return 0;
+       return OK;
+}
+
+
+//
+// dsm[.siz] expression
+// Define modulo storage
+// Quoting the Motorola assembler manual:
+// "The DSM directive reserves a block of memory the length of which in words is equal to
+// the value of <expression>.If the runtime location counter is not zero, this directive first
+// advances the runtime location counter to a base address that is a multiple of 2k, where
+// 2k >= <expression>."
+// The kicker of course is written a few sentences after:
+// "<label>, if present, will be assigned the value of the runtime location counter after a valid
+// base address has been established."
+//
+int d_dsm(WORD siz)
+{
+       TOKEN * tok_current = tok;  // Keep track of where tok was when we entered this procedure
+       uint64_t eval;
+
+       if (abs_expr(&eval) != OK)
+               return 0;
+
+       // Round up to the next highest power of 2
+       // Nicked from https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
+       eval--;
+       eval |= eval >> 1;
+       eval |= eval >> 2;
+       eval |= eval >> 4;
+       eval |= eval >> 8;
+       eval |= eval >> 16;
+
+       int units_to_skip;
+       units_to_skip = eval + 1 - sloc;
+       sloc += units_to_skip;          // Bump up sloc - TODO: check if this goes over the RAM limits?
+
+       // If a label has been defined in the same line as dsm, its value also needs to be adjusted
+       if (label_defined)
+       {
+               SYM * label = lookup(label_defined, LABEL, 0);
+               label->svalue += units_to_skip;
+       }
+
+       tok = tok_current;              // Rewind tok back to where it was
+       return d_ds(siz);               // And let d_ds take over from here
 }