/* expr.c -operands, expressions- Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc. This file is part of GAS, the GNU Assembler. GAS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GAS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GAS; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ /* * This is really a branch office of as-read.c. I split it out to clearly * distinguish the world of expressions from the world of statements. * (It also gives smaller files to re-compile.) * Here, "operand"s are of expressions, not instructions. */ #include #include #include "as.h" #include "obstack.h" #if __STDC__ == 1 static void clean_up_expression(expressionS *expressionP); #else /* __STDC__ */ static void clean_up_expression(); /* Internal. */ #endif /* not __STDC__ */ extern const char EXP_CHARS[]; /* JF hide MD floating pt stuff all the same place */ extern const char FLT_CHARS[]; /* * Build any floating-point literal here. * Also build any bignum literal here. */ /* LITTLENUM_TYPE generic_buffer [6]; */ /* JF this is a hack */ /* Seems atof_machine can backscan through generic_bignum and hit whatever happens to be loaded before it in memory. And its way too complicated for me to fix right. Thus a hack. JF: Just make generic_bignum bigger, and never write into the early words, thus they'll always be zero. I hate Dean's floating-point code. Bleh. */ LITTLENUM_TYPE generic_bignum [SIZE_OF_LARGE_NUMBER+6]; FLONUM_TYPE generic_floating_point_number = { & generic_bignum [6], /* low (JF: Was 0) */ & generic_bignum [SIZE_OF_LARGE_NUMBER+6 - 1], /* high JF: (added +6) */ 0, /* leader */ 0, /* exponent */ 0 /* sign */ }; /* If nonzero, we've been asked to assemble nan, +inf or -inf */ int generic_floating_point_magic; floating_constant(expressionP) expressionS *expressionP; { /* input_line_pointer->*/ /* floating-point constant. */ int error_code; error_code = atof_generic (& input_line_pointer, ".", EXP_CHARS, & generic_floating_point_number); if (error_code) { if (error_code == ERROR_EXPONENT_OVERFLOW) { as_bad("bad floating-point constant: exponent overflow, probably assembling junk"); } else { as_bad("bad floating-point constant: unknown error code=%d.", error_code); } } expressionP->X_seg = SEG_BIG; /* input_line_pointer->just after constant, */ /* which may point to whitespace. */ expressionP->X_add_number =-1; } integer_constant(radix, expressionP) int radix; expressionS *expressionP; { register char * digit_2; /*->2nd digit of number. */ char c; register valueT number; /* offset or (absolute) value */ register short int digit; /* value of next digit in current radix */ register short int maxdig = 0; /* highest permitted digit value. */ register int too_many_digits = 0; /* if we see >= this number of */ register char *name; /* points to name of symbol */ register symbolS * symbolP; /* points to symbol */ int small; /* true if fits in 32 bits. */ extern char hex_value[]; /* in hex_value.c */ /* may be bignum, or may fit in 32 bits. */ /* * most numbers fit into 32 bits, and we want this case to be fast. * so we pretend it will fit into 32 bits. if, after making up a 32 * bit number, we realise that we have scanned more digits than * comfortably fit into 32 bits, we re-scan the digits coding * them into a bignum. for decimal and octal numbers we are conservative: some * numbers may be assumed bignums when in fact they do fit into 32 bits. * numbers of any radix can have excess leading zeros: we strive * to recognise this and cast them back into 32 bits. * we must check that the bignum really is more than 32 * bits, and change it back to a 32-bit number if it fits. * the number we are looking for is expected to be positive, but * if it fits into 32 bits as an unsigned number, we let it be a 32-bit * number. the cavalier approach is for speed in ordinary cases. */ switch (radix) { case 2: maxdig = 2; too_many_digits = 33; break; case 8: maxdig = radix = 8; too_many_digits = 11; break; case 16: maxdig = radix = 16; too_many_digits = 9; break; case 10: maxdig = radix = 10; too_many_digits = 11; } c = *input_line_pointer; input_line_pointer++; digit_2 = input_line_pointer; for (number=0; (digit=hex_value[c])char after c. */ small = input_line_pointer - digit_2 < too_many_digits; if (! small) { /* * we saw a lot of digits. manufacture a bignum the hard way. */ LITTLENUM_TYPE * leader; /*->high order littlenum of the bignum. */ LITTLENUM_TYPE * pointer; /*->littlenum we are frobbing now. */ long carry; leader = generic_bignum; generic_bignum [0] = 0; generic_bignum [1] = 0; /* we could just use digit_2, but lets be mnemonic. */ input_line_pointer = --digit_2; /*->1st digit. */ c = *input_line_pointer++; for (; (carry = hex_value[c]) < maxdig; c = *input_line_pointer++) { for (pointer = generic_bignum; pointer <= leader; pointer++) { long work; work = carry + radix * * pointer; *pointer = work & LITTLENUM_MASK; carry = work >> LITTLENUM_NUMBER_OF_BITS; } if (carry) { if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1) { /* room to grow a longer bignum. */ *++leader = carry; } } } /* again, c is char after number, */ /* input_line_pointer->after c. */ know(sizeof (int) * 8 == 32); know(LITTLENUM_NUMBER_OF_BITS == 16); /* hence the constant "2" in the next line. */ if (leader < generic_bignum + 2) { /* will fit into 32 bits. */ number = ((generic_bignum [1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS) | (generic_bignum [0] & LITTLENUM_MASK); small = 1; } else { number = leader - generic_bignum + 1; /* number of littlenums in the bignum. */ } } if (small) { /* * here with number, in correct radix. c is the next char. * note that unlike un*x, we allow "011f" "0x9f" to * both mean the same as the (conventional) "9f". this is simply easier * than checking for strict canonical form. syntax sux! */ switch (c) { #ifdef LOCAL_LABELS_FB case 'b': { /* * backward ref to local label. * because it is backward, expect it to be defined. */ /* * construct a local label. */ name = fb_label_name((int) number, 0); /* seen before, or symbol is defined: ok */ symbolP = symbol_find(name); if ((symbolP != NULL) && (S_IS_DEFINED(symbolP))) { /* local labels are never absolute. don't waste time checking absoluteness. */ know(SEG_NORMAL(S_GET_SEGMENT(symbolP))); expressionP->X_add_symbol = symbolP; expressionP->X_seg = S_GET_SEGMENT(symbolP); } else { /* either not seen or not defined. */ as_bad("backw. ref to unknown label \"%d:\", 0 assumed.", number); expressionP->X_seg = SEG_ABSOLUTE; } expressionP->X_add_number = 0; break; } /* case 'b' */ case 'f': { /* * forward reference. expect symbol to be undefined or * unknown. undefined: seen it before. unknown: never seen * it before. * construct a local label name, then an undefined symbol. * don't create a xseg frag for it: caller may do that. * just return it as never seen before. */ name = fb_label_name((int) number, 1); symbolP = symbol_find_or_make(name); /* we have no need to check symbol properties. */ #ifndef many_segments /* since "know" puts its arg into a "string", we can't have newlines in the argument. */ know(S_GET_SEGMENT(symbolP) == SEG_UNKNOWN || S_GET_SEGMENT(symbolP) == SEG_TEXT || S_GET_SEGMENT(symbolP) == SEG_DATA); #endif expressionP->X_add_symbol = symbolP; expressionP->X_seg = SEG_UNKNOWN; expressionP->X_subtract_symbol = NULL; expressionP->X_add_number = 0; break; } /* case 'f' */ #endif /* LOCAL_LABELS_FB */ #ifdef LOCAL_LABELS_DOLLAR case '$': { /* if the dollar label is *currently* defined, then this is just another reference to it. If it is not *currently* defined, then this is a fresh instantiation of that number, so create it. */ if (dollar_label_defined(number)) { name = dollar_label_name(number, 0); symbolP = symbol_find(name); know(symbolP != NULL); } else { name = dollar_label_name(number, 1); symbolP = symbol_find_or_make(name); } expressionP->X_add_symbol = symbolP; expressionP->X_add_number = 0; expressionP->X_seg = S_GET_SEGMENT(symbolP); break; } /* case '$' */ #endif /* LOCAL_LABELS_DOLLAR */ default: { expressionP->X_add_number = number; expressionP->X_seg = SEG_ABSOLUTE; input_line_pointer--; /* restore following character. */ break; } /* really just a number */ } /* switch on char following the number */ } else { /* not a small number */ expressionP->X_add_number = number; expressionP->X_seg = SEG_BIG; input_line_pointer --; /*->char following number. */ } /* if (small) */ } /* integer_constant() */ /* * Summary of operand(). * * in: Input_line_pointer points to 1st char of operand, which may * be a space. * * out: A expressionS. X_seg determines how to understand the rest of the * expressionS. * The operand may have been empty: in this case X_seg == SEG_ABSENT. * Input_line_pointer->(next non-blank) char after operand. * */ static segT operand (expressionP) register expressionS * expressionP; { register char c; register symbolS * symbolP; /* points to symbol */ register char *name; /* points to name of symbol */ /* invented for humans only, hope */ /* optimising compiler flushes it! */ register short int radix; /* 2, 8, 10 or 16, 0 when floating */ /* 0 means we saw start of a floating- */ /* point constant. */ /* digits, assume it is a bignum. */ SKIP_WHITESPACE(); /* leading whitespace is part of operand. */ c = * input_line_pointer ++; /* input_line_pointer->past char in c. */ switch (c) { #ifdef MRI case '%': integer_constant(2, expressionP); break; case '@': integer_constant(8, expressionP); break; case '$': integer_constant(16, expressionP); break; #endif case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': input_line_pointer--; integer_constant(10, expressionP); break; case '0': /* non-decimal radix */ c = *input_line_pointer; switch (c) { default: if (c && strchr(FLT_CHARS,c)) { input_line_pointer++; floating_constant(expressionP); } else { /* The string was only zero */ expressionP->X_add_symbol = 0; expressionP->X_add_number = 0; expressionP->X_seg = SEG_ABSOLUTE; } break; case 'x': case 'X': input_line_pointer++; integer_constant(16, expressionP); break; case 'B': case 'b': input_line_pointer++; integer_constant(2, expressionP); break; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': integer_constant(8, expressionP); break; case 'f': /* if it says '0f' and the line ends or it doesn't look like a floating point #, its a local label ref. dtrt */ /* likewise for the b's. xoxorich. */ if ((c == 'f' || c == 'b' || c == 'b') && (!*input_line_pointer || (!strchr("+-.0123456789",*input_line_pointer) && !strchr(EXP_CHARS,*input_line_pointer)))) { input_line_pointer -= 2; integer_constant(10, expressionP); break; } case 'd': case 'D': case 'F': case 'r': case 'e': case 'E': case 'g': case 'G': input_line_pointer++; floating_constant(expressionP); break; } break; case '(': /* didn't begin with digit & not a name */ { (void)expression(expressionP); /* Expression() will pass trailing whitespace */ if (* input_line_pointer ++ != ')') { as_bad("Missing ')' assumed"); input_line_pointer --; } /* here with input_line_pointer->char after "(...)" */ } return expressionP->X_seg; case '\'': /* * Warning: to conform to other people's assemblers NO ESCAPEMENT is permitted * for a single quote. The next character, parity errors and all, is taken * as the value of the operand. VERY KINKY. */ expressionP->X_add_number = * input_line_pointer ++; expressionP->X_seg = SEG_ABSOLUTE; break; case '~': case '-': case '+': { /* unary operator: hope for SEG_ABSOLUTE */ switch(operand (expressionP)) { case SEG_ABSOLUTE: /* input_line_pointer -> char after operand */ if ( c=='-' ) { expressionP -> X_add_number = - expressionP -> X_add_number; /* * Notice: '-' may overflow: no warning is given. This is compatible * with other people's assemblers. Sigh. */ } else { expressionP -> X_add_number = ~ expressionP -> X_add_number; } break; case SEG_TEXT: case SEG_DATA: case SEG_BSS: case SEG_PASS1: case SEG_UNKNOWN: if(c=='-') { /* JF I hope this hack works */ expressionP->X_subtract_symbol=expressionP->X_add_symbol; expressionP->X_add_symbol=0; expressionP->X_seg=SEG_DIFFERENCE; break; } default: /* unary on non-absolute is unsuported */ as_warn("Unary operator %c ignored because bad operand follows", c); break; /* Expression undisturbed from operand(). */ } } break; case '.': if( !is_part_of_name(*input_line_pointer)) { extern struct obstack frags; /* JF: '.' is pseudo symbol with value of current location in current segment. . . */ symbolP = symbol_new("L0\001", now_seg, (valueT)(obstack_next_free(&frags)-frag_now->fr_literal), frag_now); expressionP->X_add_number=0; expressionP->X_add_symbol=symbolP; expressionP->X_seg = now_seg; break; } else { goto isname; } case ',': case '\n': /* can't imagine any other kind of operand */ expressionP->X_seg = SEG_ABSENT; input_line_pointer --; md_operand (expressionP); break; /* Fall through */ default: if (is_name_beginner(c)) /* here if did not begin with a digit */ { /* * Identifier begins here. * This is kludged for speed, so code is repeated. */ isname: name = -- input_line_pointer; c = get_symbol_end(); symbolP = symbol_find_or_make(name); /* * If we have an absolute symbol or a reg, then we know its value now. */ expressionP->X_seg = S_GET_SEGMENT(symbolP); switch (expressionP->X_seg) { case SEG_ABSOLUTE: case SEG_REGISTER: expressionP->X_add_number = S_GET_VALUE(symbolP); break; default: expressionP->X_add_number = 0; expressionP->X_add_symbol = symbolP; } * input_line_pointer = c; expressionP->X_subtract_symbol = NULL; } else { as_bad("Bad expression"); expressionP->X_add_number = 0; expressionP->X_seg = SEG_ABSOLUTE; } } /* * It is more 'efficient' to clean up the expressionS when they are created. * Doing it here saves lines of code. */ clean_up_expression (expressionP); SKIP_WHITESPACE(); /*->1st char after operand. */ know(* input_line_pointer != ' '); return (expressionP->X_seg); } /* operand() */ /* Internal. Simplify a struct expression for use by expr() */ /* * In: address of a expressionS. * The X_seg field of the expressionS may only take certain values. * Now, we permit SEG_PASS1 to make code smaller & faster. * Elsewise we waste time special-case testing. Sigh. Ditto SEG_ABSENT. * Out: expressionS may have been modified: * 'foo-foo' symbol references cancelled to 0, * which changes X_seg from SEG_DIFFERENCE to SEG_ABSOLUTE; * Unused fields zeroed to help expr(). */ static void clean_up_expression (expressionP) register expressionS * expressionP; { switch (expressionP->X_seg) { case SEG_ABSENT: case SEG_PASS1: expressionP->X_add_symbol = NULL; expressionP->X_subtract_symbol = NULL; expressionP->X_add_number = 0; break; case SEG_BIG: case SEG_ABSOLUTE: expressionP->X_subtract_symbol = NULL; expressionP->X_add_symbol = NULL; break; case SEG_UNKNOWN: expressionP->X_subtract_symbol = NULL; break; case SEG_DIFFERENCE: /* * It does not hurt to 'cancel' NULL==NULL * when comparing symbols for 'eq'ness. * It is faster to re-cancel them to NULL * than to check for this special case. */ if (expressionP->X_subtract_symbol == expressionP->X_add_symbol || (expressionP->X_subtract_symbol && expressionP->X_add_symbol && expressionP->X_subtract_symbol->sy_frag==expressionP->X_add_symbol->sy_frag && S_GET_VALUE(expressionP->X_subtract_symbol) == S_GET_VALUE(expressionP->X_add_symbol))) { expressionP->X_subtract_symbol = NULL; expressionP->X_add_symbol = NULL; expressionP->X_seg = SEG_ABSOLUTE; } break; case SEG_REGISTER: expressionP->X_add_symbol = NULL; expressionP->X_subtract_symbol = NULL; break; default: if (SEG_NORMAL(expressionP->X_seg)) { expressionP->X_subtract_symbol = NULL; } else { BAD_CASE (expressionP->X_seg); } break; } } /* clean_up_expression() */ /* * expr_part () * * Internal. Made a function because this code is used in 2 places. * Generate error or correct X_?????_symbol of expressionS. */ /* * symbol_1 += symbol_2 ... well ... sort of. */ static segT expr_part (symbol_1_PP, symbol_2_P) symbolS ** symbol_1_PP; symbolS * symbol_2_P; { segT return_value; #ifndef MANY_SEGMENTS know((* symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == SEG_TEXT) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_DATA) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_BSS) || (!S_IS_DEFINED(* symbol_1_PP))); know(symbol_2_P == NULL || (S_GET_SEGMENT(symbol_2_P) == SEG_TEXT) || (S_GET_SEGMENT(symbol_2_P) == SEG_DATA) || (S_GET_SEGMENT(symbol_2_P) == SEG_BSS) || (!S_IS_DEFINED(symbol_2_P))); #endif if (* symbol_1_PP) { if (!S_IS_DEFINED(* symbol_1_PP)) { if (symbol_2_P) { return_value = SEG_PASS1; * symbol_1_PP = NULL; } else { know(!S_IS_DEFINED(* symbol_1_PP)); return_value = SEG_UNKNOWN; } } else { if (symbol_2_P) { if (!S_IS_DEFINED(symbol_2_P)) { * symbol_1_PP = NULL; return_value = SEG_PASS1; } else { /* {seg1} - {seg2} */ as_bad("Expression too complex, 2 symbolS forgotten: \"%s\" \"%s\"", S_GET_NAME(* symbol_1_PP), S_GET_NAME(symbol_2_P)); * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } else { return_value = S_GET_SEGMENT(* symbol_1_PP); } } } else { /* (* symbol_1_PP) == NULL */ if (symbol_2_P) { * symbol_1_PP = symbol_2_P; return_value = S_GET_SEGMENT(symbol_2_P); } else { * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } #ifndef MANY_SEGMENTS know(return_value == SEG_ABSOLUTE || return_value == SEG_TEXT || return_value == SEG_DATA || return_value == SEG_BSS || return_value == SEG_UNKNOWN || return_value == SEG_PASS1); #endif know((*symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == return_value)); return (return_value); } /* expr_part() */ /* Expression parser. */ /* * We allow an empty expression, and just assume (absolute,0) silently. * Unary operators and parenthetical expressions are treated as operands. * As usual, Q==quantity==operand, O==operator, X==expression mnemonics. * * We used to do a aho/ullman shift-reduce parser, but the logic got so * warped that I flushed it and wrote a recursive-descent parser instead. * Now things are stable, would anybody like to write a fast parser? * Most expressions are either register (which does not even reach here) * or 1 symbol. Then "symbol+constant" and "symbol-symbol" are common. * So I guess it doesn't really matter how inefficient more complex expressions * are parsed. * * After expr(RANK,resultP) input_line_pointer->operator of rank <= RANK. * Also, we have consumed any leading or trailing spaces (operand does that) * and done all intervening operators. */ typedef enum { O_illegal, /* (0) what we get for illegal op */ O_multiply, /* (1) * */ O_divide, /* (2) / */ O_modulus, /* (3) % */ O_left_shift, /* (4) < */ O_right_shift, /* (5) > */ O_bit_inclusive_or, /* (6) | */ O_bit_or_not, /* (7) ! */ O_bit_exclusive_or, /* (8) ^ */ O_bit_and, /* (9) & */ O_add, /* (10) + */ O_subtract /* (11) - */ } operatorT; #define __ O_illegal static const operatorT op_encoding [256] = { /* maps ASCII->operators */ __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_or_not, __, __, __, O_modulus, O_bit_and, __, __, __, O_multiply, O_add, __, O_subtract, __, O_divide, __, __, __, __, __, __, __, __, __, __, __, __, O_left_shift, __, O_right_shift, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_exclusive_or, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_inclusive_or, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __ }; /* * Rank Examples * 0 operand, (expression) * 1 + - * 2 & ^ ! | * 3 * / % << >> */ static const operator_rankT op_rank [] = { 0, 3, 3, 3, 3, 3, 2, 2, 2, 2, 1, 1 }; /* Return resultP->X_seg. */ segT expr(rank, resultP) register operator_rankT rank; /* Larger # is higher rank. */ register expressionS *resultP; /* Deliver result here. */ { expressionS right; register operatorT op_left; register char c_left; /* 1st operator character. */ register operatorT op_right; register char c_right; know(rank >= 0); (void)operand (resultP); know(* input_line_pointer != ' '); /* Operand() gobbles spaces. */ c_left = * input_line_pointer; /* Potential operator character. */ op_left = op_encoding [c_left]; while (op_left != O_illegal && op_rank [(int) op_left] > rank) { input_line_pointer ++; /*->after 1st character of operator. */ /* Operators "<<" and ">>" have 2 characters. */ if (* input_line_pointer == c_left && (c_left == '<' || c_left == '>')) { input_line_pointer ++; } /*->after operator. */ if (SEG_ABSENT == expr (op_rank[(int) op_left], &right)) { as_warn("Missing operand value assumed absolute 0."); resultP->X_add_number = 0; resultP->X_subtract_symbol = NULL; resultP->X_add_symbol = NULL; resultP->X_seg = SEG_ABSOLUTE; } know(* input_line_pointer != ' '); c_right = * input_line_pointer; op_right = op_encoding [c_right]; if (* input_line_pointer == c_right && (c_right == '<' || c_right == '>')) { input_line_pointer ++; } /*->after operator. */ know((int) op_right == 0 || op_rank [(int) op_right] <= op_rank[(int) op_left]); /* input_line_pointer->after right-hand quantity. */ /* left-hand quantity in resultP */ /* right-hand quantity in right. */ /* operator in op_left. */ if (resultP->X_seg == SEG_PASS1 || right . X_seg == SEG_PASS1) { resultP->X_seg = SEG_PASS1; } else { if (resultP->X_seg == SEG_BIG) { as_warn("Left operand of %c is a %s. Integer 0 assumed.", c_left, resultP->X_add_number > 0 ? "bignum" : "float"); resultP->X_seg = SEG_ABSOLUTE; resultP->X_add_symbol = 0; resultP->X_subtract_symbol = 0; resultP->X_add_number = 0; } if (right . X_seg == SEG_BIG) { as_warn("Right operand of %c is a %s. Integer 0 assumed.", c_left, right . X_add_number > 0 ? "bignum" : "float"); right . X_seg = SEG_ABSOLUTE; right . X_add_symbol = 0; right . X_subtract_symbol = 0; right . X_add_number = 0; } if (op_left == O_subtract) { /* * Convert - into + by exchanging symbolS and negating number. * I know -infinity can't be negated in 2's complement: * but then it can't be subtracted either. This trick * does not cause any further inaccuracy. */ register symbolS * symbolP; right . X_add_number = - right . X_add_number; symbolP = right . X_add_symbol; right . X_add_symbol = right . X_subtract_symbol; right . X_subtract_symbol = symbolP; if (symbolP) { right . X_seg = SEG_DIFFERENCE; } op_left = O_add; } if (op_left == O_add) { segT seg1; segT seg2; #ifndef MANY_SEGMENTS know(resultP->X_seg == SEG_DATA || resultP->X_seg == SEG_TEXT || resultP->X_seg == SEG_BSS || resultP->X_seg == SEG_UNKNOWN || resultP->X_seg == SEG_DIFFERENCE || resultP->X_seg == SEG_ABSOLUTE || resultP->X_seg == SEG_PASS1 || resultP->X_seg == SEG_REGISTER); know(right.X_seg == SEG_DATA || right.X_seg == SEG_TEXT || right.X_seg == SEG_BSS || right.X_seg == SEG_UNKNOWN || right.X_seg == SEG_DIFFERENCE || right.X_seg == SEG_ABSOLUTE || right.X_seg == SEG_PASS1); #endif clean_up_expression (& right); clean_up_expression (resultP); seg1 = expr_part (& resultP->X_add_symbol, right . X_add_symbol); seg2 = expr_part (& resultP->X_subtract_symbol, right . X_subtract_symbol); if (seg1 == SEG_PASS1 || seg2 == SEG_PASS1) { need_pass_2 = 1; resultP->X_seg = SEG_PASS1; } else if (seg2 == SEG_ABSOLUTE) resultP->X_seg = seg1; else if (seg1 != SEG_UNKNOWN && seg1 != SEG_ABSOLUTE && seg2 != SEG_UNKNOWN && seg1 != seg2) { know(seg2 != SEG_ABSOLUTE); know(resultP->X_subtract_symbol); #ifndef MANY_SEGMENTS know(seg1 == SEG_TEXT || seg1 == SEG_DATA || seg1== SEG_BSS); know(seg2 == SEG_TEXT || seg2 == SEG_DATA || seg2== SEG_BSS); #endif know(resultP->X_add_symbol); know(resultP->X_subtract_symbol); as_bad("Expression too complex: forgetting %s - %s", S_GET_NAME(resultP->X_add_symbol), S_GET_NAME(resultP->X_subtract_symbol)); resultP->X_seg = SEG_ABSOLUTE; /* Clean_up_expression() will do the rest. */ } else resultP->X_seg = SEG_DIFFERENCE; resultP->X_add_number += right . X_add_number; clean_up_expression (resultP); } else { /* Not +. */ if (resultP->X_seg == SEG_UNKNOWN || right . X_seg == SEG_UNKNOWN) { resultP->X_seg = SEG_PASS1; need_pass_2 = 1; } else { resultP->X_subtract_symbol = NULL; resultP->X_add_symbol = NULL; /* Will be SEG_ABSOLUTE. */ if (resultP->X_seg != SEG_ABSOLUTE || right . X_seg != SEG_ABSOLUTE) { as_bad("Relocation error. Absolute 0 assumed."); resultP->X_seg = SEG_ABSOLUTE; resultP->X_add_number = 0; } else { switch (op_left) { case O_bit_inclusive_or: resultP->X_add_number |= right . X_add_number; break; case O_modulus: if (right . X_add_number) { resultP->X_add_number %= right . X_add_number; } else { as_warn("Division by 0. 0 assumed."); resultP->X_add_number = 0; } break; case O_bit_and: resultP->X_add_number &= right . X_add_number; break; case O_multiply: resultP->X_add_number *= right . X_add_number; break; case O_divide: if (right . X_add_number) { resultP->X_add_number /= right . X_add_number; } else { as_warn("Division by 0. 0 assumed."); resultP->X_add_number = 0; } break; case O_left_shift: resultP->X_add_number <<= right . X_add_number; break; case O_right_shift: resultP->X_add_number >>= right . X_add_number; break; case O_bit_exclusive_or: resultP->X_add_number ^= right . X_add_number; break; case O_bit_or_not: resultP->X_add_number |= ~ right . X_add_number; break; default: BAD_CASE(op_left); break; } /* switch(operator) */ } } /* If we have to force need_pass_2. */ } /* If operator was +. */ } /* If we didn't set need_pass_2. */ op_left = op_right; } /* While next operator is >= this rank. */ return (resultP->X_seg); } /* * get_symbol_end() * * This lives here because it belongs equally in expr.c & read.c. * Expr.c is just a branch office read.c anyway, and putting it * here lessens the crowd at read.c. * * Assume input_line_pointer is at start of symbol name. * Advance input_line_pointer past symbol name. * Turn that character into a '\0', returning its former value. * This allows a string compare (RMS wants symbol names to be strings) * of the symbol name. * There will always be a char following symbol name, because all good * lines end in end-of-line. */ char get_symbol_end() { register char c; while (is_part_of_name(c = * input_line_pointer ++)) ; * -- input_line_pointer = 0; return (c); } unsigned int get_single_number() { expressionS exp; operand(&exp); return exp.X_add_number; } /* * Local Variables: * comment-column: 0 * fill-column: 131 * End: */ /* end of expr.c */