]> Shamusworld >> Repos - rmac/blobdiff - expr.c
Version bump for last commit. :-)
[rmac] / expr.c
diff --git a/expr.c b/expr.c
index 5474af8c36fa9cec7fd7506e5d230641d47f1462..e597257007880205a9032aea705581dee55e31cd 100644 (file)
--- a/expr.c
+++ b/expr.c
@@ -1,7 +1,7 @@
 //
-// RMAC - Reboot's Macro Assembler for all Atari computers
+// RMAC - Renamed Macro Assembler for all Atari computers
 // EXPR.C - Expression Analyzer
-// Copyright (C) 199x Landon Dyer, 2011-2017 Reboot and Friends
+// Copyright (C) 199x Landon Dyer, 2011-2021 Reboot and Friends
 // RMAC derived from MADMAC v1.07 Written by Landon Dyer, 1986
 // Source utilised with the kind permission of Landon Dyer
 //
@@ -35,8 +35,8 @@ char itokcl[] = {
        CR_DEFINED, CR_REFERENCED,              // SUNARY (special unary)
        CR_STREQ, CR_MACDEF,
        CR_DATE, CR_TIME,
-       CR_ABSCOUNT, 0,
-       '!', '~', UNMINUS, 0,                   // UNARY
+       CR_ABSCOUNT, CR_FILESIZE, 0,
+       '!', '~', UNMINUS, UNLT, UNGT, 0,       // UNARY
        '*', '/', '%', 0,                               // MULT
        '+', '-', 0,                                    // ADD
        SHL, SHR, 0,                                    // SHIFT
@@ -49,6 +49,7 @@ char itokcl[] = {
 
 const char missym_error[] = "missing symbol";
 const char str_error[] = "missing symbol or string";
+const char noflt_error[] = "operator not usable with float";
 
 // Convert expression to postfix
 static PTR evalTokenBuffer;            // Deposit tokens here (this is really a
@@ -57,7 +58,6 @@ static PTR evalTokenBuffer;           // Deposit tokens here (this is really a
                                                                // riscasm.c)
 static int symbolNum;                  // Pointer to the entry in symbolPtr[]
 
-
 //
 // Obtain a string value
 //
@@ -71,7 +71,6 @@ static uint32_t str_value(char * p)
        return v;
 }
 
-
 //
 // Initialize expression analyzer
 //
@@ -94,28 +93,99 @@ void InitExpression(void)
        symbolNum = 0;
 }
 
+extern int correctMathRules;
+int xor(void);
+int and(void);
+int rel(void);
+int shift(void);
+int sum(void);
+int product(void);
 
 //
-// Binary operators (all the same precedence)
+// Binary operators (all the same precedence,
+// except if -4 is passed to the command line)
 //
+#define precedence(HIERARCHY_HIGHER, HIERARCHY_CURRENT) \
+do \
+{ \
+       if (HIERARCHY_HIGHER() != OK) \
+               return ERROR; \
+       while (tokenClass[*tok] == HIERARCHY_CURRENT) \
+       { \
+               TOKEN t = *tok++; \
+               if (HIERARCHY_HIGHER() != OK) \
+                       return ERROR; \
+               *evalTokenBuffer.u32++ = t; \
+       } \
+}while (0)
+
 int expr0(void)
 {
-       if (expr1() != OK)
-               return ERROR;
-
-       while (tokenClass[*tok] >= MULT)
+       if ( correctMathRules == 0 )
        {
-               TOKEN t = *tok++;
-
                if (expr1() != OK)
                        return ERROR;
 
-               *evalTokenBuffer.u32++ = t;
+               while (tokenClass[*tok] >= MULT)
+               {
+                       TOKEN t = *tok++;
+
+                       if (expr1() != OK)
+                               return ERROR;
+
+                       *evalTokenBuffer.u32++ = t;
+               }
        }
+       else
+       {
+               // The order of C precedence (lower to higher):
+               // bitwise XOR ^
+               // bitwise OR |
+               // bitwise AND &
+               // relational = < <= >= > !=
+               // shifts << >>
+               // sum + -
+               // product * /
+               precedence(xor, OR);
+       }
+       return OK;
+}
+
+int xor(void)
+{
+       precedence(and, XOR);
+       return OK;
+}
+
+int and(void)
+{
+       precedence(rel, AND);
+       return OK;
+}
+
+int rel(void)
+{
+       precedence(shift, REL);
+       return OK;
+}
+
+int shift(void)
+{
+       precedence(sum, SHIFT);
+       return OK;
+}
 
+int sum(void)
+{
+       precedence(product, ADD);
        return OK;
 }
 
+int product(void)
+{
+       precedence(expr1, MULT);
+       return OK;
+}
 
 //
 // Unary operators (detect unary '-')
@@ -125,23 +195,24 @@ int expr0(void)
 //
 int expr1(void)
 {
-       TOKEN t;
-       SYM * sy;
-       char * p, * p2;
+       char * p;
        WORD w;
-       int j;
 
        int class = tokenClass[*tok];
 
-       if (*tok == '-' || *tok == '+' || class == UNARY)
+       if (*tok == '-' || *tok == '+' || *tok == '<' || *tok == '>' || class == UNARY)
        {
-               t = *tok++;
+               TOKEN t = *tok++;
 
                if (expr2() != OK)
                        return ERROR;
 
                if (t == '-')
                        t = UNMINUS;
+               else if (t == '<')
+                       t = UNLT;
+               else if (t == '>')
+                       t = UNGT;
 
                // With leading + we don't have to deposit anything to the buffer
                // because there's no unary '+' nor we have to do anything about it
@@ -153,8 +224,53 @@ int expr1(void)
                switch (*tok++)
                {
                case CR_ABSCOUNT:
+                       if (cursect != ABS)
+                       {
+                               *evalTokenBuffer.u32++ = CONST;
+                               *evalTokenBuffer.u64++ = sect[ABS].sloc;
+                       }
+                       else
+                       {
+                               *evalTokenBuffer.u32++ = CONST;
+                               *evalTokenBuffer.u64++ = sloc;
+                       }
+                       break;
+               case CR_FILESIZE:
+                       if (*tok++ != STRING)
+                               return error("^^FILESIZE expects filename inside string");
                        *evalTokenBuffer.u32++ = CONST;
-                       *evalTokenBuffer.u64++ = (uint64_t)sect[ABS].sloc;
+                       // @@copypasted from d_incbin, maybe factor this out somehow?
+                       // Attempt to open the include file in the current directory, then (if that
+                       // failed) try list of include files passed in the enviroment string or by
+                       // the "-d" option.
+                       int fd, i;
+                       char buf1[256];
+
+                       if ((fd = open(string[*tok], _OPEN_INC)) < 0)
+                       {
+                               for(i=0; nthpath("RMACPATH", i, buf1)!=0; i++)
+                               {
+                                       fd = strlen(buf1);
+
+                                       // Append path char if necessary
+                                       if ((fd > 0) && (buf1[fd - 1] != SLASHCHAR))
+                                               strcat(buf1, SLASHSTRING);
+
+                                       strcat(buf1, string[*tok]);
+
+                                       if ((fd = open(buf1, _OPEN_INC)) >= 0)
+                                               goto allright;
+                               }
+
+                               return error("cannot open: \"%s\"", string[*tok]);
+                       }
+
+allright:
+                       *evalTokenBuffer.u64++ = (uint64_t)lseek(fd, 0L, SEEK_END);
+                       close(fd);
+
+                       // Advance tok because of consumed string token
+                       tok++;
                        break;
                case CR_TIME:
                        *evalTokenBuffer.u32++ = CONST;
@@ -183,8 +299,9 @@ getsym:
                                return error(missym_error);
 
                        p = string[*tok++];
-                       j = (*p == '.' ? curenv : 0);
-                       w = ((sy = lookup(p, LABEL, j)) != NULL && (sy->sattr & w) ? 1 : 0);
+                       int j = (*p == '.' ? curenv : 0);
+                       SYM * sy = lookup(p, LABEL, j);
+                       w = ((sy != NULL) && (sy->sattr & w ? 1 : 0));
                        *evalTokenBuffer.u32++ = CONST;
                        *evalTokenBuffer.u64++ = (uint64_t)w;
                        break;
@@ -201,7 +318,7 @@ getsym:
                        if (*tok != SYMBOL && *tok != STRING)
                                return error(str_error);
 
-                       p2 = string[tok[1]];
+                       char * p2 = string[tok[1]];
                        tok += 2;
 
                        w = (WORD)(!strcmp(p, p2));
@@ -216,15 +333,11 @@ getsym:
        return OK;
 }
 
-
 //
 // Terminals (CONSTs) and parenthesis grouping
 //
 int expr2(void)
 {
-       char * p;
-       SYM * sy;
-       int j;
        PTR ptk;
 
        switch (*tok++)
@@ -237,33 +350,25 @@ int expr2(void)
                break;
        case FCONST:
                ptk.u32 = tok;
-               *evalTokenBuffer.u32++ = CONST;
+               *evalTokenBuffer.u32++ = FCONST;
                *evalTokenBuffer.u64++ = *ptk.u64++;
                tok = ptk.u32;
                break;
        case SYMBOL:
-               p = string[*tok++];
-               j = (*p == '.' ? curenv : 0);
-               sy = lookup(p, LABEL, j);
+       {
+               char * p = string[*tok++];
+               int j = (*p == '.' ? curenv : 0);
+               SYM * sy = lookup(p, LABEL, j);
 
                if (sy == NULL)
                        sy = NewSymbol(p, LABEL, j);
 
-               // Check register bank usage
-               if (sy->sattre & EQUATEDREG)
-               {
-                       if ((regbank == BANK_0) && (sy->sattre & BANK_1) && !altbankok)
-                               warn("equated symbol \'%s\' cannot be used in register bank 0", sy->sname);
-
-                       if ((regbank == BANK_1) && (sy->sattre & BANK_0) && !altbankok)
-                               warn("equated symbol \'%s\' cannot be used in register bank 1", sy->sname);
-               }
-
                *evalTokenBuffer.u32++ = SYMBOL;
                *evalTokenBuffer.u32++ = symbolNum;
                symbolPtr[symbolNum] = sy;
                symbolNum++;
                break;
+       }
        case STRING:
                *evalTokenBuffer.u32++ = CONST;
                *evalTokenBuffer.u64++ = str_value(string[*tok++]);
@@ -301,7 +406,7 @@ int expr2(void)
        case '$':
                *evalTokenBuffer.u32++ = ACONST;                        // Attributed const
                *evalTokenBuffer.u32++ = sloc;                          // Current location
-               *evalTokenBuffer.u32++ = cursect | DEFINED;     // Store attribs
+               *evalTokenBuffer.u32++ = DEFINED | ((orgactive | org68k_active) ? 0 : cursect);         // Store attribs
                break;
        case '*':
                *evalTokenBuffer.u32++ = ACONST;                        // Attributed const
@@ -309,7 +414,8 @@ int expr2(void)
                // pcloc == location at start of line
                *evalTokenBuffer.u32++ = (orgactive ? orgaddr : pcloc);
                // '*' takes attributes of current section, not ABS!
-               *evalTokenBuffer.u32++ = cursect | DEFINED;
+               // Also, if we're ORG'd, the symbol is absolute
+               *evalTokenBuffer.u32++ = DEFINED | ((orgactive | org68k_active) ? 0 : cursect);
                break;
        default:
                return error("bad expression");
@@ -318,7 +424,6 @@ int expr2(void)
        return OK;
 }
 
-
 //
 // Recursive-descent expression analyzer (with some simple speed hacks)
 //
@@ -334,49 +439,24 @@ int expr(TOKEN * otk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
        PTR ptk;
 
        evalTokenBuffer.u32 = otk;      // Set token pointer to 'exprbuf' (direct.c)
-                                                       // Also set in various other places too (riscasm.c,
-                                                       // e.g.)
+                                                               // Also set in various other places too (riscasm.c,
+                                                               // e.g.)
 
-//printf("expr(): tokens 0-2: %i %i %i (%c %c %c); tc[2] = %i\n", tok[0], tok[1], tok[2], tok[0], tok[1], tok[2], tokenClass[tok[2]]);
        // Optimize for single constant or single symbol.
-       // Shamus: Subtle bug here. EOL token is 101; if you have a constant token
-       //         followed by the value 101, it will trigger a bad evaluation here.
-       //         This is probably a really bad assumption to be making here...!
-       //         (assuming tok[1] == EOL is a single token that is)
-       //         Seems that even other tokens (SUNARY type) can fuck this up too.
-#if 0
-//     if ((tok[1] == EOL)
-       if ((tok[1] == EOL && ((tok[0] != CONST || tok[0] != FCONST) && tokenClass[tok[0]] != SUNARY))
-//             || (((*tok == CONST || *tok == FCONST || *tok == SYMBOL) || (*tok >= KW_R0 && *tok <= KW_R31))
-//             && (tokenClass[tok[2]] < UNARY)))
-               || (((tok[0] == SYMBOL) || (tok[0] >= KW_R0 && tok[0] <= KW_R31))
-                       && (tokenClass[tok[2]] < UNARY))
-               || ((tok[0] == CONST || tok[0] == FCONST) && (tokenClass[tok[3]] < UNARY))
-               )
-#else
-// Shamus: Seems to me that this could be greatly simplified by 1st checking if the first token is a multibyte token, *then* checking if there's an EOL after it depending on the actual length of the token (multiple vs. single). Otherwise, we have the horror show that is the following:
+       // Shamus: Seems to me that this could be greatly simplified by 1st
+       //         checking if the first token is a multibyte token, *then*
+       //         checking if there's an EOL after it depending on the actual
+       //         length of the token (multiple vs. single). Otherwise, we have
+       //         the horror show that is the following:
        if ((tok[1] == EOL
                        && (tok[0] != CONST && tokenClass[tok[0]] != SUNARY))
-               || (((tok[0] == SYMBOL)
-                               || (tok[0] >= KW_R0 && tok[0] <= KW_R31))
+               || ((tok[0] == SYMBOL)
                        && (tokenClass[tok[2]] < UNARY))
                || ((tok[0] == CONST) && (tokenClass[tok[3]] < UNARY))
                )
-// Shamus: Yes, you can parse that out and make some kind of sense of it, but damn, it takes a while to get it and understand the subtle bugs that result from not being careful about what you're checking; especially vis-a-vis niavely checking tok[1] for an EOL. O_o
-#endif
+// Shamus: Yes, you can parse that out and make some kind of sense of it, but damn, it takes a while to get it and understand the subtle bugs that result from not being careful about what you're checking; especially vis-a-vis naively checking tok[1] for an EOL. O_o
        {
-               if (*tok >= KW_R0 && *tok <= KW_R31)
-               {
-                       *evalTokenBuffer.u32++ = CONST;
-                       *evalTokenBuffer.u64++ = *a_value = (*tok - KW_R0);
-                       *a_attr = ABS | DEFINED;
-
-                       if (a_esym != NULL)
-                               *a_esym = NULL;
-
-                       tok++;
-               }
-               else if (*tok == CONST)
+               if (*tok == CONST)
                {
                        ptk.u32 = tok;
                        *evalTokenBuffer.u32++ = *ptk.u32++;
@@ -410,13 +490,18 @@ int expr(TOKEN * otk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
                {
                        *evalTokenBuffer.u32++ = CONST;
 
-                       if (orgactive)
+                       if (orgactive | org68k_active)
+                       {
                                *evalTokenBuffer.u64++ = *a_value = orgaddr;
+                               *a_attr = DEFINED;      // We have ORG active, it doesn't belong in a section!
+                       }
                        else
+                       {
                                *evalTokenBuffer.u64++ = *a_value = pcloc;
+                               // '*' takes attributes of current section, not ABS!
+                               *a_attr = cursect | DEFINED;
+                       }
 
-                       // '*' takes attributes of current section, not ABS!
-                       *a_attr = cursect | DEFINED;
 
                        if (a_esym != NULL)
                                *a_esym = NULL;
@@ -428,11 +513,6 @@ int expr(TOKEN * otk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
                        p = string[tok[1]];
                        j = (*p == '.' ? curenv : 0);
                        symbol = lookup(p, LABEL, j);
-#if 0
-printf("eval: Looking up symbol (%s) [=%08X]\n", p, symbol);
-if (symbol)
-       printf("      attr=%04X, attre=%08X, val=%i, name=%s\n", symbol->sattr, symbol->sattre, symbol->svalue, symbol->sname);
-#endif
 
                        if (symbol == NULL)
                                symbol = NewSymbol(p, LABEL, j);
@@ -446,18 +526,6 @@ if (symbol)
                        if ((symbol->sattre & UNDEF_EQUR) && !riscImmTokenSeen)
                        {
                                error("undefined register equate '%s'", symbol->sname);
-//if we return right away, it returns some spurious errors...
-//                             return ERROR;
-                       }
-
-                       // Check register bank usage
-                       if (symbol->sattre & EQUATEDREG)
-                       {
-                               if ((regbank == BANK_0) && (symbol->sattre & BANK_1) && !altbankok)
-                                       warn("equated symbol '%s' cannot be used in register bank 0", symbol->sname);
-
-                               if ((regbank == BANK_1) && (symbol->sattre & BANK_0) && !altbankok)
-                                       warn("equated symbol '%s' cannot be used in register bank 1", symbol->sname);
                        }
 
                        *evalTokenBuffer.u32++ = SYMBOL;
@@ -474,19 +542,14 @@ be converted from a linked list into an array).
                        symbolNum++;
 #endif
 
-                       if (symbol->sattr & DEFINED)
-                               *a_value = symbol->svalue;
-                       else
-                               *a_value = 0;
+                       *a_value = (symbol->sattr & DEFINED ? symbol->svalue : 0);
+                       *a_attr = (WORD)(symbol->sattr & ~GLOBAL);
 
-/*
-All that extra crap that was put into the svalue when doing the equr stuff is
-thrown away right here. What the hell is it for?
-*/
                        if (symbol->sattre & EQUATEDREG)
-                               *a_value &= 0x1F;
-
-                       *a_attr = (WORD)(symbol->sattr & ~GLOBAL);
+                       {
+                               *a_attr |= RISCREG; // Mark it as a register, 'cause it is
+                               *a_esym = symbol;
+                       }
 
                        if ((symbol->sattr & (GLOBAL | DEFINED)) == GLOBAL
                                && a_esym != NULL)
@@ -494,10 +557,15 @@ thrown away right here. What the hell is it for?
 
                        tok += 2;
                }
+               // Holy hell... This is likely due to the fact that LSR is mistakenly set as a SUNARY type... Need to fix this... !!! FIX !!!
+               else if (m6502)
+               {
+                       *evalTokenBuffer.u32++ = *tok++;
+               }
                else
                {
                        // Unknown type here... Alert the user!,
-                       error("undefined RISC register in expression");
+                       error("undefined RISC register in expression [token=$%X]", *tok);
                        // Prevent spurious error reporting...
                        tok++;
                        return ERROR;
@@ -514,16 +582,15 @@ thrown away right here. What the hell is it for?
        return evexpr(otk, a_value, a_attr, a_esym);
 }
 
-
 //
 // Evaluate expression.
 // If the expression involves only ONE external symbol, the expression is
-// UNDEFINED, but it's value includes everything but the symbol value, and
+// UNDEFINED, but its value includes everything but the symbol value, and
 // 'a_esym' is set to the external symbol.
 //
 int evexpr(TOKEN * _tk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
 {
-       WORD attr, attr2;
+       WORD attr;
        SYM * sy;
        uint64_t * sval = evstk;                                // (Empty) initial stack
        WORD * sattr = evattr;
@@ -537,7 +604,6 @@ int evexpr(TOKEN * _tk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
                switch ((int)*tk.u32++)
                {
                case SYMBOL:
-//printf("evexpr(): SYMBOL\n");
                        sy = symbolPtr[*tk.u32++];
                        sy->sattr |= REFERENCED;                // Set "referenced" bit
 
@@ -558,30 +624,27 @@ int evexpr(TOKEN * _tk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
                        }
 
                        if (sy->sattr & DEFINED)
-                       {
                                *++sval = sy->svalue;           // Push symbol's value
-                       }
                        else
-                       {
                                *++sval = 0;                            // 0 for undefined symbols
-                       }
 
                        *++sattr = (WORD)(sy->sattr & ~GLOBAL); // Push attribs
                        sym_seg = (WORD)(sy->sattr & TDB);
                        break;
+
                case CONST:
                        *++sval = *tk.u64++;
-//printf("evexpr(): CONST = %lX\n", *sval);
                        *++sattr = ABS | DEFINED;               // Push simple attribs
                        break;
+
                case FCONST:
-//printf("evexpr(): FCONST = %i\n", *tk.u32);
-                       *((double *)sval) = *((double *)tk.u32);
-                       tk.u32 += 2;
+                       // Even though it's a double, we can treat it like a uint64_t since
+                       // we're just moving the bits around.
+                       *++sval = *tk.u64++;
                        *++sattr = ABS | DEFINED | FLOAT; // Push simple attribs
                        break;
+
                case ACONST:
-//printf("evexpr(): ACONST = %i\n", *tk.u32);
                        *++sval = *tk.u32++;                            // Push value
                        *++sattr = (WORD)*tk.u32++;                     // Push attribs
                        break;
@@ -597,92 +660,62 @@ int evexpr(TOKEN * _tk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
                        //
                        //   [1] + : Error
                        //       - : ABS
+
                case '+':
-//printf("evexpr(): +\n");
                        --sval;                                                 // Pop value
                        --sattr;                                                // Pop attrib
-//printf("--> N+N: %i + %i = ", *sval, sval[1]);
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
-                       attr2 = sattr[0] | sattr[1] & FLOAT; // Returns FLOAT if either of the two numbers are FLOAT
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
+                       // Since adding an int to a fp value promotes it to a fp value, we
+                       // don't care whether it's first or second; we cast to to a double
+                       // regardless.
+                       if (attr == FLOAT)
                        {
-                               // Float + Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *dst += *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float + Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *dst += *src;
-                       }
-                       else if (attr == FLOAT >> 1)
-                       {
-                               // Int + Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *(double *)dst = *src + *dst;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *(double *)sval = fpval1 + fpval2;
                        }
                        else
                        {
                                *sval += sval[1];                               // Compute value
                        }
-//printf("%i\n", *sval);
 
                        if (!(*sattr & TDB))
-                               *sattr = sattr[1] | attr2;
+                               *sattr = sattr[1] | attr;
                        else if (sattr[1] & TDB)
                                return error(seg_error);
 
                        break;
+
                case '-':
-//printf("evexpr(): -\n");
                        --sval;                                                 // Pop value
                        --sattr;                                                // Pop attrib
-//printf("--> N-N: %i - %i = ", *sval, sval[1]);
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
-                       attr2 = sattr[0] | sattr[1] & FLOAT; // Returns FLOAT if either of the two numbers are FLOAT
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
+                       // Since subtracting an int to a fp value promotes it to a fp
+                       // value, we don't care whether it's first or second; we cast to to
+                       // a double regardless.
+                       if (attr == FLOAT)
                        {
-                               // Float - Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *dst -= *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float - Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *dst -= *src;
-                       }
-                       else if (attr == FLOAT >> 1)
-                       {
-                               // Int - Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *(double *)dst = *dst - *src;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *(double *)sval = fpval1 - fpval2;
                        }
                        else
                        {
-                               *sval -= sval[1];                               // Compute value
+                               *sval -= sval[1];
                        }
 
-//printf("%i\n", *sval);
-
+                       *sattr |= attr;                                 // Inherit FLOAT attribute
                        attr = (WORD)(*sattr & TDB);
-#if 0
-printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
-#endif
-                       *sattr |= attr2;                // Inherit FLOAT attribute
                        // If symbol1 is ABS, take attributes from symbol2
                        if (!attr)
                                *sattr = sattr[1];
@@ -691,26 +724,49 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                *sattr &= ~TDB;
 
                        break;
+
                // Unary operators only work on ABS items
                case UNMINUS:
-//printf("evexpr(): UNMINUS\n");
                        if (*sattr & TDB)
                                return error(seg_error);
 
                        if (*sattr & FLOAT)
                        {
-                               double *dst = (double *)sval;
+                               double * dst = (double *)sval;
                                *dst = -*dst;
                                *sattr = ABS | DEFINED | FLOAT; // Expr becomes absolute
                        }
                        else
                        {
-                               *sval = -(int)*sval;
+                               *sval = -(int64_t)*sval;
                                *sattr = ABS | DEFINED;                 // Expr becomes absolute
                        }
+
+                       break;
+
+               case UNLT: // Unary < (get the low byte of a word)
+                       if (*sattr & TDB)
+                               return error(seg_error);
+
+                       if (*sattr & FLOAT)
+                               return error(noflt_error);
+
+                       *sval = (int64_t)((*sval) & 0x00FF);
+                       *sattr = ABS | DEFINED;                 // Expr becomes absolute
+                       break;
+
+               case UNGT: // Unary > (get the high byte of a word)
+                       if (*sattr & TDB)
+                               return error(seg_error);
+
+                       if (*sattr & FLOAT)
+                               return error(noflt_error);
+
+                       *sval = (int64_t)(((*sval) >> 8) & 0x00FF);
+                       *sattr = ABS | DEFINED;                 // Expr becomes absolute
                        break;
+
                case '!':
-//printf("evexpr(): !\n");
                        if (*sattr & TDB)
                                return error(seg_error);
 
@@ -720,8 +776,8 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                        *sval = !*sval;
                        *sattr = ABS | DEFINED;                 // Expr becomes absolute
                        break;
+
                case '~':
-//printf("evexpr(): ~\n");
                        if (*sattr & TDB)
                                return error(seg_error);
 
@@ -731,344 +787,243 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                        *sval = ~*sval;
                        *sattr = ABS | DEFINED;                 // Expr becomes absolute
                        break;
+
                // Comparison operators must have two values that
                // are in the same segment, but that's the only requirement.
                case LE:
-//printf("evexpr(): LE\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Float <= Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst <= *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float <= Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *sval = *dst <= *src;
-                       }
-                       else if (attr == FLOAT >> 1)
-                       {
-                               // Int <= Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst <= *src;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 <= fpval2);
                        }
                        else
                        {
-                               *sval = *sval <= sval[1];
+                               *sval = (*sval <= sval[1]);
                        }
 
                        *sattr = ABS | DEFINED;
                        break;
+
                case GE:
-//printf("evexpr(): GE\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
-                       {
-                               // Float >= Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst >= *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float >= Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *sval = *dst >= *src;
-                       }
-                       else if (attr == FLOAT >> 1)
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Int >= Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst >= *src;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 >= fpval2);
                        }
-                       else if (attr == 0)
+                       else
                        {
-                               *sval = *sval >= sval[1];
+                               *sval = (*sval >= sval[1]);
                        }
-                       else
-                               *sattr = ABS | DEFINED;
 
+                       *sattr = ABS | DEFINED;
                        break;
+
                case '>':
-//printf("evexpr(): >\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Float > Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst > *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float > Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *sval = *dst > *src;
-                       }
-                       else if (attr == FLOAT >> 1)
-                       {
-                               // Int > Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst > *src;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 > fpval2);
                        }
                        else
                        {
-                               *sval = *sval > sval[1];
+                               *sval = (*sval > sval[1]);
                        }
 
                        *sattr = ABS | DEFINED;
-
                        break;
+
                case '<':
-//printf("evexpr(): <\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Float < Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst < *src;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float < Int
-                               double * dst = (double *)sval;
-                               uint64_t * src = (uint64_t *)(sval + 1);
-                               *sval = *dst < *src;
-                       }
-                       else if (attr == FLOAT >> 1)
-                       {
-                               // Int < Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *dst < *src;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 < fpval2);
                        }
                        else
                        {
-                               *sval = *sval < sval[1];
+                               *sval = (*sval < sval[1]);
                        }
 
-                       *sattr = ABS | DEFINED;
-
+                       *sattr = ABS | DEFINED;         // Expr forced to ABS
                        break;
+
                case NE:
-//printf("evexpr(): NE\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
-                       {
-                               // Float <> Float
-                               return error("comparison for equality with float types not allowed.");
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float <> Int
-                               return error("comparison for equality with float types not allowed.");
-                       }
-                       else if (attr == FLOAT >> 1)
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Int != Float
-                               return error("comparison for equality with float types not allowed.");
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 != fpval2);
                        }
                        else
                        {
-                               *sval = *sval != sval[1];
+                               *sval = (*sval != sval[1]);
                        }
 
-                       *sattr = ABS | DEFINED;
-
+                       *sattr = ABS | DEFINED;         // Expr forced to ABS
                        break;
+
                case '=':
-//printf("evexpr(): =\n");
                        sattr--;
                        sval--;
 
                        if ((*sattr & TDB) != (sattr[1] & TDB))
                                return error(seg_error);
 
-                       // Extract float attributes from both terms and pack them
-                       // into a single value
-                       attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
+                       // Get FLOAT attribute, if any
+                       attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                       if (attr == (FLOAT | (FLOAT >> 1)))
-                       {
-                               // Float = Float
-                               double * dst = (double *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *src == *dst;
-                       }
-                       else if (attr == FLOAT)
-                       {
-                               // Float = Int
-                               return error("equality with float ");
-                       }
-                       else if (attr == FLOAT >> 1)
+                       // Cast any ints in the comparison to double, if there's at least
+                       // one double in the comparison.
+                       if (attr == FLOAT)
                        {
-                               // Int == Float
-                               uint64_t * dst = (uint64_t *)sval;
-                               double * src = (double *)(sval + 1);
-                               *sval = *src == *dst;
+                               PTR p;
+                               p.u64 = sval;
+                               double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                               p.u64++;
+                               double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                               *sval = (fpval1 == fpval2);
                        }
                        else
                        {
-                               *sval = *sval == sval[1];
+                               *sval = (*sval == sval[1]);
                        }
 
-                       *sattr = ABS | DEFINED;
+                       *sattr = ABS | DEFINED;         // Expr forced to ABS
 
                        break;
+
                // All other binary operators must have two ABS items to work with.
                // They all produce an ABS value.
+               // Shamus: Is this true? There's at least one counterexample of legit
+               //         code where this assumption fails to produce correct code.
                default:
-//printf("evexpr(): default\n");
-                       // GH - Removed for v1.0.15 as part of the fix for indexed loads.
-                       //if ((*sattr & (TEXT|DATA|BSS)) || (*--sattr & (TEXT|DATA|BSS)))
-                       //error(seg_error);
 
                        switch ((int)tk.u32[-1])
                        {
                        case '*':
                                sval--;
-                               sattr--;                                        // Pop attrib
-//printf("--> NxN: %i x %i = ", *sval, sval[1]);
-                               // Extract float attributes from both terms and pack them
-                               // into a single value
-                               attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
-                               attr2 = sattr[0] | sattr[1] & FLOAT; // Returns FLOAT if either of the two numbers are FLOAT
+                               sattr--;
+                               // Get FLOAT attribute, if any
+                               attr = (sattr[0] | sattr[1]) & FLOAT;
 
-                               if (attr == (FLOAT | (FLOAT >> 1)))
-                               {
-                                       // Float * Float
-                                       double * dst = (double *)sval;
-                                       double * src = (double *)(sval + 1);
-                                       *dst *= *src;
-                               }
-                               else if (attr == FLOAT)
-                               {
-                                       // Float * Int
-                                       double * dst = (double *)sval;
-                                       uint64_t * src = (uint64_t *)(sval + 1);
-                                       *dst *= *src;
-                               }
-                               else if (attr == FLOAT >> 1)
+                               // Since multiplying an int to a fp value promotes it to a fp
+                               // value, we don't care whether it's first or second; it will
+                               // be cast to a double regardless.
+/*
+An open question here is do we promote ints to floats as signed or unsigned? It makes a difference if, say, the int is put in as -1 but is promoted to a double as $FFFFFFFFFFFFFFFF--you get very different results that way! For now, we promote as signed until proven detrimental otherwise.
+*/
+                               if (attr == FLOAT)
                                {
-                                       // Int * Float
-                                       uint64_t * dst = (uint64_t *)sval;
-                                       double * src = (double *)(sval + 1);
-                                       *(double *)dst = *src * *dst;
+                                       PTR p;
+                                       p.u64 = sval;
+                                       double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                                       p.u64++;
+                                       double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
+                                       *(double *)sval = fpval1 * fpval2;
                                }
                                else
                                {
                                        *sval *= sval[1];
                                }
-//printf("%i\n", *sval);
-
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
-                               *sattr |= attr2;
 
                                break;
+
                        case '/':
                                sval--;
-                               sattr--;                                        // Pop attrib
+                               sattr--;
+                               // Get FLOAT attribute, if any
+                               attr = (sattr[0] | sattr[1]) & FLOAT;
 
-
-//printf("--> N/N: %i / %i = ", sval[0], sval[1]);
-                               // Extract float attributes from both terms and pack them
-                               // into a single value
-                               attr = sattr[0] & FLOAT | ((sattr[1] & FLOAT) >> 1);
-                               attr2 = sattr[0] | sattr[1] & FLOAT; // Returns FLOAT if either of the two numbers are FLOAT
-
-                               if (attr == (FLOAT | (FLOAT >> 1)))
-                               {
-                                       // Float / Float
-                                       double * dst = (double *)sval;
-                                       double * src = (double *)(sval + 1);
-
-                                       if (*src == 0)
-                                               return error("divide by zero");
-
-                                       *dst = *dst / *src;
-                               }
-                               else if (attr == FLOAT)
+                               if (attr == FLOAT)
                                {
-                                       // Float / Int
-                                       double * dst = (double *)sval;
-                                       uint64_t * src = (uint64_t *)(sval + 1);
+                                       PTR p;
+                                       p.u64 = sval;
+                                       double fpval1 = (sattr[0] & FLOAT ? *p.dp : (double)*p.i64);
+                                       p.u64++;
+                                       double fpval2 = (sattr[1] & FLOAT ? *p.dp : (double)*p.i64);
 
-                                       if (*src == 0)
+                                       if (fpval2 == 0)
                                                return error("divide by zero");
 
-                                       *dst = *dst / *src;
-                               }
-                               else if (attr == FLOAT >> 1)
-                               {
-                                       // Int / Float
-                                       uint64_t * dst=(uint64_t *)sval;
-                                       double * src=(double *)(sval + 1);
-
-                                       if (*src == 0)
-                                               return error("divide by zero");
-
-                                       *(double *)dst = *dst / *src;
+                                       *(double *)sval = fpval1 / fpval2;
                                }
                                else
                                {
                                        if (sval[1] == 0)
                                                return error("divide by zero");
-//printf("--> N/N: %i / %i = ", sval[0], sval[1]);
 
                                        // Compiler is picky here: Without casting these, it
                                        // discards the sign if dividing a negative # by a
@@ -1078,14 +1033,11 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                        *sval = (int32_t)sval[0] / (int32_t)sval[1];
                                }
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
-                               *sattr |= attr2;
-
-//printf("%i\n", *sval);
                                break;
+
                        case '%':
                                sval--;
-                               sattr--;                                        // Pop attrib
+                               sattr--;
 
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '%'.");
@@ -1093,9 +1045,9 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                if (sval[1] == 0)
                                        return error("mod (%) by zero");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval %= sval[1];
                                break;
+
                        case SHL:
                                sval--;
                                sattr--;                                        // Pop attrib
@@ -1103,9 +1055,9 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '<<'.");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval <<= sval[1];
                                break;
+
                        case SHR:
                                sval--;
                                sattr--;                                        // Pop attrib
@@ -1113,9 +1065,9 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '>>'.");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval >>= sval[1];
                                break;
+
                        case '&':
                                sval--;
                                sattr--;                                        // Pop attrib
@@ -1123,9 +1075,9 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '&'.");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval &= sval[1];
                                break;
+
                        case '^':
                                sval--;
                                sattr--;                                        // Pop attrib
@@ -1133,21 +1085,22 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '^'.");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval ^= sval[1];
                                break;
+
                        case '|':
                                sval--;
-                               sattr--;                                        // Pop attrib
+                               sattr--;
 
                                if ((*sattr | sattr[1]) & FLOAT)
                                        return error("floating point numbers not allowed with operator '|'.");
 
-                               *sattr = ABS | DEFINED;                 // Expr becomes absolute
                                *sval |= sval[1];
                                break;
+
                        default:
-                               interror(5);                            // Bad operator in expression stream
+                               // Bad operator in expression stream (this should never happen!)
+                               interror(5);
                        }
                }
        }
@@ -1158,14 +1111,32 @@ printf("EVEXPR (-): sym1 = %X, sym2 = %X\n", attr, sattr[1]);
        if (a_esym != NULL)
                *a_esym = esym;
 
-       // sym_seg added in 1.0.16 to solve a problem with forward symbols in
-       // expressions where absolute values also existed. The absolutes were
-       // overiding the symbol segments and not being included :(
-       //*a_attr = *sattr | sym_seg;           // Copy value + attrib
-
-       *a_attr = *sattr;                                               // Copy value + attrib
+       // Copy value + attrib into return variables
        *a_value = *sval;
+       *a_attr = *sattr;
 
        return OK;
 }
 
+//
+// Count the # of tokens in the passed in expression
+// N.B.: 64-bit constants count as two tokens each
+//
+uint16_t ExpressionLength(TOKEN * tk)
+{
+       uint16_t length;
+
+       for(length=0; tk[length]!=ENDEXPR; length++)
+       {
+               // Add one to length for 2X tokens, two for 3X tokens
+               if (tk[length] == SYMBOL)
+                       length++;
+               else if ((tk[length] == CONST) || (tk[length] == FCONST))
+                       length += 2;
+       }
+
+       // Add 1 for ENDEXPR
+       length++;
+
+       return length;
+}