/* expr.c -operands, expressions- Copyright (C) 1987 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 1, 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. */ #ifndef lint static char rcsid[] = "$Id: expr.c,v 1.2 1993/08/02 17:28:12 mycroft Exp $"; #endif /* not lint */ /* * 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 "as.h" #include "flonum.h" #include "read.h" #include "struc-symbol.h" #include "expr.h" #include "obstack.h" #include "symbols.h" static void clean_up_expression(); /* Internal. */ extern const char EXP_CHARS[]; /* JF hide MD floating pt stuff all the same place */ extern const char FLT_CHARS[]; #ifdef SUN_ASM_SYNTAX extern int local_label_defined[]; #endif /* * 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; /* * 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_NONE. * Input_line_pointer -> (next non-blank) char after operand. * */ static segT operand (expressionP) register expressionS * expressionP; { register char c; register char *name; /* points to name of symbol */ register struct symbol * symbolP; /* Points to symbol */ extern char hex_value[]; /* In hex_value.c */ char *local_label_name(); SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */ c = * input_line_pointer ++; /* Input_line_pointer -> past char in c. */ if (isdigit(c)) { register valueT number; /* offset or (absolute) value */ register short int digit; /* value of next digit in current radix */ /* invented for humans only, hope */ /* optimising compiler flushes it! */ register short int radix; /* 8, 10 or 16 */ /* 0 means we saw start of a floating- */ /* point constant. */ register short int maxdig;/* Highest permitted digit value. */ register int too_many_digits; /* If we see >= this number of */ /* digits, assume it is a bignum. */ register char * digit_2; /* -> 2nd digit of number. */ int small; /* TRUE if fits in 32 bits. */ if (c=='0') { /* non-decimal radix */ if ((c = * input_line_pointer ++)=='x' || c=='X') { c = * input_line_pointer ++; /* read past "0x" or "0X" */ maxdig = radix = 16; too_many_digits = 9; } else { /* If it says '0f' and the line ends or it DOESN'T look like a floating point #, its a local label ref. DTRT */ if(c=='f' && (! *input_line_pointer || (!index("+-.0123456789",*input_line_pointer) && !index(EXP_CHARS,*input_line_pointer)))) { maxdig = radix = 10; too_many_digits = 11; c='0'; input_line_pointer-=2; } else if (c && index (FLT_CHARS,c)) { radix = 0; /* Start of floating-point constant. */ /* input_line_pointer -> 1st char of number. */ expressionP -> X_add_number = - (isupper(c) ? tolower(c) : c); } else { /* By elimination, assume octal radix. */ radix = 8; maxdig = 10; /* Un*x sux. Compatibility. */ too_many_digits = 11; } } /* c == char after "0" or "0x" or "0X" or "0e" etc.*/ } else { maxdig = radix = 10; too_many_digits = 11; } if (radix) { /* Fixed-point integer constant. */ /* 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. */ 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 int 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 int 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( BITS_PER_INT == 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 = TRUE; } 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! */ if (number<10) { #ifdef SUN_ASM_SYNTAX if (c=='b' || (c=='$' && local_label_defined[number])) #else if (c=='b') #endif { /* * Backward ref to local label. * Because it is backward, expect it to be DEFINED. */ /* * Construct a local label. */ name = local_label_name ((int)number, 0); if ( (symbolP = symbol_table_lookup(name)) /* seen before */ && (symbolP -> sy_type & N_TYPE) != N_UNDF /* symbol is defined: OK */ ) { /* Expected path: symbol defined. */ /* Local labels are never absolute. Don't waste time checking absoluteness. */ know( (symbolP -> sy_type & N_TYPE) == N_DATA || (symbolP -> sy_type & N_TYPE) == N_TEXT ); expressionP -> X_add_symbol = symbolP; expressionP -> X_add_number = 0; expressionP -> X_seg = N_TYPE_seg [symbolP -> sy_type]; } else { /* Either not seen or not defined. */ as_warn( "Backw. ref to unknown label \"%d:\", 0 assumed.", number ); expressionP -> X_add_number = 0; expressionP -> X_seg = SEG_ABSOLUTE; } } else { #ifdef SUN_ASM_SYNTAX if (c=='f' || (c=='$' && !local_label_defined[number])) #else if (c=='f') #endif { /* * Forward reference. Expect symbol to be undefined or * unknown. Undefined: seen it before. Unknown: never seen * it in this pass. * 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 = local_label_name ((int)number, 1); if ( symbolP = symbol_table_lookup( name )) { /* We have no need to check symbol properties. */ know( (symbolP -> sy_type & N_TYPE) == N_UNDF || (symbolP -> sy_type & N_TYPE) == N_DATA || (symbolP -> sy_type & N_TYPE) == N_TEXT); } else { symbolP = symbol_new (name, N_UNDF, 0,0,0, & zero_address_frag); symbol_table_insert (symbolP); } expressionP -> X_add_symbol = symbolP; expressionP -> X_seg = SEG_UNKNOWN; expressionP -> X_subtract_symbol = NULL; expressionP -> X_add_number = 0; } else { /* Really a number, not a local label. */ expressionP -> X_add_number = number; expressionP -> X_seg = SEG_ABSOLUTE; input_line_pointer --; /* Restore following character. */ } /* if (c=='f') */ } /* if (c=='b') */ } else { /* Really a number. */ expressionP -> X_add_number = number; expressionP -> X_seg = SEG_ABSOLUTE; input_line_pointer --; /* Restore following character. */ } /* if (number<10) */ } else { expressionP -> X_add_number = number; expressionP -> X_seg = SEG_BIG; input_line_pointer --; /* -> char following number. */ } /* if (small) */ } /* (If integer constant) */ else { /* 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_warn( "Bad floating-point constant: exponent overflow, probably assembling junk" ); } else { as_warn( "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. */ know( expressionP -> X_add_number < 0 ); /* < 0 means "floating point". */ } /* if (not floating-point constant) */ } else if(c=='.' && !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", (unsigned char)(seg_N_TYPE[(int)now_seg]), 0, 0, (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; } else 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. */ name = -- input_line_pointer; c = get_symbol_end(); symbolP = symbol_table_lookup(name); if (symbolP) { /* * If we have an absolute symbol, then we know it's value now. */ register segT seg; seg = N_TYPE_seg [(int) symbolP -> sy_type & N_TYPE]; if ((expressionP -> X_seg = seg) == SEG_ABSOLUTE ) { expressionP -> X_add_number = symbolP -> sy_value; } else { expressionP -> X_add_number = 0; expressionP -> X_add_symbol = symbolP; } } else { expressionP -> X_add_symbol = symbolP = symbol_new (name, N_UNDF, 0,0,0, & zero_address_frag); expressionP -> X_add_number = 0; expressionP -> X_seg = SEG_UNKNOWN; symbol_table_insert (symbolP); } * input_line_pointer = c; expressionP -> X_subtract_symbol = NULL; } else if (c=='(')/* didn't begin with digit & not a name */ { (void)expression( expressionP ); /* Expression() will pass trailing whitespace */ if ( * input_line_pointer ++ != ')' ) { as_warn( "Missing ')' assumed"); input_line_pointer --; } /* here with input_line_pointer -> char after "(...)" */ } else if ( c=='~' || c=='-' ) { /* 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(). */ } } else if (c=='\'') { /* * 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; } else { /* can't imagine any other kind of operand */ expressionP -> X_seg = SEG_NONE; input_line_pointer --; } /* * 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_NONE. * 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_NONE: 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_TEXT: case SEG_DATA: case SEG_BSS: 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 && expressionP->X_subtract_symbol->sy_value==expressionP->X_add_symbol->sy_value)) { expressionP -> X_subtract_symbol = NULL; expressionP -> X_add_symbol = NULL; expressionP -> X_seg = SEG_ABSOLUTE; } break; default: BAD_CASE( expressionP -> X_seg); break; } } /* * 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) struct symbol ** symbol_1_PP; struct symbol * symbol_2_P; { segT return_value; know( (* symbol_1_PP) == NULL || ((* symbol_1_PP) -> sy_type & N_TYPE) == N_TEXT || ((* symbol_1_PP) -> sy_type & N_TYPE) == N_DATA || ((* symbol_1_PP) -> sy_type & N_TYPE) == N_BSS || ((* symbol_1_PP) -> sy_type & N_TYPE) == N_UNDF ); know( symbol_2_P == NULL || (symbol_2_P -> sy_type & N_TYPE) == N_TEXT || (symbol_2_P -> sy_type & N_TYPE) == N_DATA || (symbol_2_P -> sy_type & N_TYPE) == N_BSS || (symbol_2_P -> sy_type & N_TYPE) == N_UNDF ); if (* symbol_1_PP) { if (((* symbol_1_PP) -> sy_type & N_TYPE) == N_UNDF) { if (symbol_2_P) { return_value = SEG_PASS1; * symbol_1_PP = NULL; } else { know( ((* symbol_1_PP) -> sy_type & N_TYPE) == N_UNDF) return_value = SEG_UNKNOWN; } } else { if (symbol_2_P) { if ((symbol_2_P -> sy_type & N_TYPE) == N_UNDF) { * symbol_1_PP = NULL; return_value = SEG_PASS1; } else { /* {seg1} - {seg2} */ as_warn( "Expression too complex, 2 symbols forgotten: \"%s\" \"%s\"", (* symbol_1_PP) -> sy_name, symbol_2_P -> sy_name ); * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } else { return_value = N_TYPE_seg [(* symbol_1_PP) -> sy_type & N_TYPE]; } } } else { /* (* symbol_1_PP) == NULL */ if (symbol_2_P) { * symbol_1_PP = symbol_2_P; return_value = N_TYPE_seg [(symbol_2_P) -> sy_type & N_TYPE]; } else { * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } 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 ); know( (* symbol_1_PP) == NULL || ((* symbol_1_PP) -> sy_type & N_TYPE) == seg_N_TYPE [(int) 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 * / % < > */ typedef char operator_rankT; static const operator_rankT op_rank [] = { 0, 3, 3, 3, 3, 3, 2, 2, 2, 2, 1, 1 }; segT /* Return resultP -> X_seg. */ 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_NONE == 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 struct symbol * 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; 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 ); 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 ); 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 = TRUE; 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 ); know( seg1 == SEG_TEXT || seg1 == SEG_DATA || seg1== SEG_BSS ); know( seg2 == SEG_TEXT || seg2 == SEG_DATA || seg2== SEG_BSS ); know( resultP -> X_add_symbol ); know( resultP -> X_subtract_symbol ); as_warn("Expression too complex: forgetting %s - %s", resultP -> X_add_symbol -> sy_name, resultP -> X_subtract_symbol -> sy_name); 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 = TRUE; } 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_warn( "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); } /* end: expr.c */