1115 lines
31 KiB
C
1115 lines
31 KiB
C
/* expr.c -operands, expressions-
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Copyright (C) 1987, 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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/*
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* This is really a branch office of as-read.c. I split it out to clearly
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* distinguish the world of expressions from the world of statements.
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* (It also gives smaller files to re-compile.)
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* Here, "operand"s are of expressions, not instructions.
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*/
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#include <ctype.h>
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#include <string.h>
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#include "as.h"
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#include "obstack.h"
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static void floating_constant PARAMS ((expressionS * expressionP));
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static void integer_constant PARAMS ((int radix, expressionS * expressionP));
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static void clean_up_expression PARAMS ((expressionS * expressionP));
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static symbolS *make_expr_symbol PARAMS ((expressionS * expressionP));
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extern const char EXP_CHARS[], FLT_CHARS[];
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/* Build a dummy symbol to hold a complex expression. This is how we
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build expressions up out of other expressions. The symbol is put
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into the fake section expr_section. */
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static symbolS *
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make_expr_symbol (expressionP)
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expressionS *expressionP;
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{
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const char *fake;
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symbolS *symbolP;
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if (expressionP->X_op == O_symbol
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&& expressionP->X_add_number == 0)
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return expressionP->X_add_symbol;
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/* FIXME: This should be something which decode_local_label_name
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will handle. */
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fake = FAKE_LABEL_NAME;
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/* Putting constant symbols in absolute_section rather than
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expr_section is convenient for the old a.out code, for which
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S_GET_SEGMENT does not always retrieve the value put in by
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S_SET_SEGMENT. */
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symbolP = symbol_new (fake,
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(expressionP->X_op == O_constant
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? absolute_section
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: expr_section),
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0, &zero_address_frag);
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symbolP->sy_value = *expressionP;
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if (expressionP->X_op == O_constant)
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resolve_symbol_value (symbolP);
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return symbolP;
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}
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/*
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* Build any floating-point literal here.
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* Also build any bignum literal here.
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*/
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/* Seems atof_machine can backscan through generic_bignum and hit whatever
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happens to be loaded before it in memory. And its way too complicated
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for me to fix right. Thus a hack. JF: Just make generic_bignum bigger,
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and never write into the early words, thus they'll always be zero.
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I hate Dean's floating-point code. Bleh. */
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LITTLENUM_TYPE generic_bignum[SIZE_OF_LARGE_NUMBER + 6];
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FLONUM_TYPE generic_floating_point_number =
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{
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&generic_bignum[6], /* low (JF: Was 0) */
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&generic_bignum[SIZE_OF_LARGE_NUMBER + 6 - 1], /* high JF: (added +6) */
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0, /* leader */
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0, /* exponent */
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0 /* sign */
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};
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/* If nonzero, we've been asked to assemble nan, +inf or -inf */
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int generic_floating_point_magic;
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static void
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floating_constant (expressionP)
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expressionS *expressionP;
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{
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/* input_line_pointer->*/
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/* floating-point constant. */
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int error_code;
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error_code = atof_generic (&input_line_pointer, ".", EXP_CHARS,
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&generic_floating_point_number);
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if (error_code)
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{
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if (error_code == ERROR_EXPONENT_OVERFLOW)
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{
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as_bad ("bad floating-point constant: exponent overflow, probably assembling junk");
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}
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else
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{
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as_bad ("bad floating-point constant: unknown error code=%d.", error_code);
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}
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}
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expressionP->X_op = O_big;
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/* input_line_pointer->just after constant, */
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/* which may point to whitespace. */
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expressionP->X_add_number = -1;
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}
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static void
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integer_constant (radix, expressionP)
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int radix;
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expressionS *expressionP;
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{
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char *start; /* start of number. */
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char c;
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valueT number; /* offset or (absolute) value */
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short int digit; /* value of next digit in current radix */
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short int maxdig = 0;/* highest permitted digit value. */
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int too_many_digits = 0; /* if we see >= this number of */
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char *name; /* points to name of symbol */
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symbolS *symbolP; /* points to symbol */
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int small; /* true if fits in 32 bits. */
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extern const char hex_value[]; /* in hex_value.c */
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/* May be bignum, or may fit in 32 bits. */
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/* Most numbers fit into 32 bits, and we want this case to be fast.
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so we pretend it will fit into 32 bits. If, after making up a 32
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bit number, we realise that we have scanned more digits than
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comfortably fit into 32 bits, we re-scan the digits coding them
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into a bignum. For decimal and octal numbers we are
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conservative: Some numbers may be assumed bignums when in fact
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they do fit into 32 bits. Numbers of any radix can have excess
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leading zeros: We strive to recognise this and cast them back
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into 32 bits. We must check that the bignum really is more than
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32 bits, and change it back to a 32-bit number if it fits. The
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number we are looking for is expected to be positive, but if it
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fits into 32 bits as an unsigned number, we let it be a 32-bit
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number. The cavalier approach is for speed in ordinary cases. */
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/* This has been extended for 64 bits. We blindly assume that if
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you're compiling in 64-bit mode, the target is a 64-bit machine.
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This should be cleaned up. */
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#ifdef BFD64
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#define valuesize 64
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#else /* includes non-bfd case, mostly */
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#define valuesize 32
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#endif
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switch (radix)
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{
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case 2:
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maxdig = 2;
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too_many_digits = valuesize + 1;
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break;
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case 8:
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maxdig = radix = 8;
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too_many_digits = (valuesize + 2) / 3 + 1;
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break;
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case 16:
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maxdig = radix = 16;
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too_many_digits = (valuesize + 3) / 4 + 1;
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break;
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case 10:
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maxdig = radix = 10;
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too_many_digits = (valuesize + 12) / 4; /* very rough */
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}
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#undef valuesize
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start = input_line_pointer;
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c = *input_line_pointer++;
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for (number = 0;
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(digit = hex_value[(unsigned char) c]) < maxdig;
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c = *input_line_pointer++)
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{
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number = number * radix + digit;
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}
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/* c contains character after number. */
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/* input_line_pointer->char after c. */
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small = (input_line_pointer - start - 1) < too_many_digits;
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if (!small)
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{
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/*
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* we saw a lot of digits. manufacture a bignum the hard way.
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*/
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LITTLENUM_TYPE *leader; /*->high order littlenum of the bignum. */
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LITTLENUM_TYPE *pointer; /*->littlenum we are frobbing now. */
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long carry;
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leader = generic_bignum;
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generic_bignum[0] = 0;
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generic_bignum[1] = 0;
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input_line_pointer = start; /*->1st digit. */
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c = *input_line_pointer++;
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for (;
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(carry = hex_value[(unsigned char) c]) < maxdig;
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c = *input_line_pointer++)
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{
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for (pointer = generic_bignum;
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pointer <= leader;
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pointer++)
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{
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long work;
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work = carry + radix * *pointer;
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*pointer = work & LITTLENUM_MASK;
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carry = work >> LITTLENUM_NUMBER_OF_BITS;
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}
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if (carry)
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{
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if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1)
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{
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/* room to grow a longer bignum. */
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*++leader = carry;
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}
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}
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}
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/* again, c is char after number, */
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/* input_line_pointer->after c. */
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know (LITTLENUM_NUMBER_OF_BITS == 16);
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if (leader < generic_bignum + 2)
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{
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/* will fit into 32 bits. */
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number =
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((generic_bignum[1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS)
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| (generic_bignum[0] & LITTLENUM_MASK);
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small = 1;
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}
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else
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{
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number = leader - generic_bignum + 1; /* number of littlenums in the bignum. */
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}
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}
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if (small)
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{
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/*
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* here with number, in correct radix. c is the next char.
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* note that unlike un*x, we allow "011f" "0x9f" to
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* both mean the same as the (conventional) "9f". this is simply easier
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* than checking for strict canonical form. syntax sux!
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*/
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switch (c)
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{
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#ifdef LOCAL_LABELS_FB
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case 'b':
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{
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/*
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* backward ref to local label.
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* because it is backward, expect it to be defined.
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*/
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/* Construct a local label. */
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name = fb_label_name ((int) number, 0);
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/* seen before, or symbol is defined: ok */
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symbolP = symbol_find (name);
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if ((symbolP != NULL) && (S_IS_DEFINED (symbolP)))
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{
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/* local labels are never absolute. don't waste time
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checking absoluteness. */
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know (SEG_NORMAL (S_GET_SEGMENT (symbolP)));
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expressionP->X_op = O_symbol;
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expressionP->X_add_symbol = symbolP;
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}
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else
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{
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/* either not seen or not defined. */
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/* @@ Should print out the original string instead of
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the parsed number. */
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as_bad ("backw. ref to unknown label \"%d:\", 0 assumed.",
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(int) number);
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expressionP->X_op = O_constant;
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}
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||
expressionP->X_add_number = 0;
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break;
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} /* case 'b' */
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case 'f':
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{
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/*
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* forward reference. expect symbol to be undefined or
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* unknown. undefined: seen it before. unknown: never seen
|
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* it before.
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* construct a local label name, then an undefined symbol.
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* don't create a xseg frag for it: caller may do that.
|
||
* just return it as never seen before.
|
||
*/
|
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name = fb_label_name ((int) number, 1);
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symbolP = symbol_find_or_make (name);
|
||
/* we have no need to check symbol properties. */
|
||
#ifndef many_segments
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/* since "know" puts its arg into a "string", we
|
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can't have newlines in the argument. */
|
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know (S_GET_SEGMENT (symbolP) == undefined_section || S_GET_SEGMENT (symbolP) == text_section || S_GET_SEGMENT (symbolP) == data_section);
|
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#endif
|
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expressionP->X_op = O_symbol;
|
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expressionP->X_add_symbol = symbolP;
|
||
expressionP->X_add_number = 0;
|
||
|
||
break;
|
||
} /* case 'f' */
|
||
|
||
#endif /* LOCAL_LABELS_FB */
|
||
|
||
#ifdef LOCAL_LABELS_DOLLAR
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||
|
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case '$':
|
||
{
|
||
|
||
/* If the dollar label is *currently* defined, then this is just
|
||
another reference to it. If it is not *currently* defined,
|
||
then this is a fresh instantiation of that number, so create
|
||
it. */
|
||
|
||
if (dollar_label_defined ((long) number))
|
||
{
|
||
name = dollar_label_name ((long) number, 0);
|
||
symbolP = symbol_find (name);
|
||
know (symbolP != NULL);
|
||
}
|
||
else
|
||
{
|
||
name = dollar_label_name ((long) number, 1);
|
||
symbolP = symbol_find_or_make (name);
|
||
}
|
||
|
||
expressionP->X_op = O_symbol;
|
||
expressionP->X_add_symbol = symbolP;
|
||
expressionP->X_add_number = 0;
|
||
|
||
break;
|
||
} /* case '$' */
|
||
|
||
#endif /* LOCAL_LABELS_DOLLAR */
|
||
|
||
default:
|
||
{
|
||
expressionP->X_op = O_constant;
|
||
expressionP->X_add_number = number;
|
||
input_line_pointer--; /* restore following character. */
|
||
break;
|
||
} /* really just a number */
|
||
|
||
} /* switch on char following the number */
|
||
|
||
}
|
||
else
|
||
{
|
||
/* not a small number */
|
||
expressionP->X_op = O_big;
|
||
expressionP->X_add_number = number; /* number of littlenums */
|
||
input_line_pointer--; /*->char following number. */
|
||
}
|
||
}
|
||
|
||
|
||
/*
|
||
* Summary of operand().
|
||
*
|
||
* in: Input_line_pointer points to 1st char of operand, which may
|
||
* be a space.
|
||
*
|
||
* out: A expressionS.
|
||
* The operand may have been empty: in this case X_op == O_absent.
|
||
* Input_line_pointer->(next non-blank) char after operand.
|
||
*/
|
||
|
||
static segT
|
||
operand (expressionP)
|
||
expressionS *expressionP;
|
||
{
|
||
char c;
|
||
symbolS *symbolP; /* points to symbol */
|
||
char *name; /* points to name of symbol */
|
||
segT segment;
|
||
|
||
/* All integers are regarded as unsigned unless they are negated.
|
||
This is because the only thing which cares whether a number is
|
||
unsigned is the code in emit_expr which extends constants into
|
||
bignums. It should only sign extend negative numbers, so that
|
||
something like ``.quad 0x80000000'' is not sign extended even
|
||
though it appears negative if valueT is 32 bits. */
|
||
expressionP->X_unsigned = 1;
|
||
|
||
/* 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);
|
||
expressionP->X_add_number = -(isupper (c) ? tolower (c) : c);
|
||
}
|
||
else
|
||
{
|
||
/* The string was only zero */
|
||
expressionP->X_op = O_constant;
|
||
expressionP->X_add_number = 0;
|
||
}
|
||
|
||
break;
|
||
|
||
case 'x':
|
||
case 'X':
|
||
input_line_pointer++;
|
||
integer_constant (16, expressionP);
|
||
break;
|
||
|
||
case 'b':
|
||
#ifdef LOCAL_LABELS_FB
|
||
switch (input_line_pointer[1])
|
||
{
|
||
case '+':
|
||
case '-':
|
||
/* If unambiguously a difference expression, treat it as
|
||
one by indicating a label; otherwise, it's always a
|
||
binary number. */
|
||
{
|
||
char *cp = input_line_pointer + 1;
|
||
while (strchr ("0123456789", *++cp))
|
||
;
|
||
if (*cp == 'b' || *cp == 'f')
|
||
goto is_0b_label;
|
||
}
|
||
goto is_0b_binary;
|
||
case '0': case '1':
|
||
/* Some of our code elsewhere does permit digits greater
|
||
than the expected base; for consistency, do the same
|
||
here. */
|
||
case '2': case '3': case '4': case '5':
|
||
case '6': case '7': case '8': case '9':
|
||
goto is_0b_binary;
|
||
case 0:
|
||
goto is_0b_label;
|
||
default:
|
||
goto is_0b_label;
|
||
}
|
||
is_0b_label:
|
||
input_line_pointer--;
|
||
integer_constant (10, expressionP);
|
||
break;
|
||
is_0b_binary:
|
||
#endif
|
||
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':
|
||
#ifdef LOCAL_LABELS_FB
|
||
/* If it says "0f" and it could possibly be a floating point
|
||
number, make it one. Otherwise, make it a local label,
|
||
and try to deal with parsing the rest later. */
|
||
if (!input_line_pointer[1]
|
||
|| (is_end_of_line[0xff & input_line_pointer[1]]))
|
||
goto is_0f_label;
|
||
{
|
||
char *cp = input_line_pointer + 1;
|
||
int r = atof_generic (&cp, ".", EXP_CHARS,
|
||
&generic_floating_point_number);
|
||
switch (r)
|
||
{
|
||
case 0:
|
||
case ERROR_EXPONENT_OVERFLOW:
|
||
if (*cp == 'f' || *cp == 'b')
|
||
/* looks like a difference expression */
|
||
goto is_0f_label;
|
||
else
|
||
goto is_0f_float;
|
||
default:
|
||
as_fatal ("expr.c(operand): bad atof_generic return val %d",
|
||
r);
|
||
}
|
||
}
|
||
|
||
/* Okay, now we've sorted it out. We resume at one of these
|
||
two labels, depending on what we've decided we're probably
|
||
looking at. */
|
||
is_0f_label:
|
||
input_line_pointer--;
|
||
integer_constant (10, expressionP);
|
||
break;
|
||
|
||
is_0f_float:
|
||
/* fall through */
|
||
#endif
|
||
|
||
case 'd':
|
||
case 'D':
|
||
case 'F':
|
||
case 'r':
|
||
case 'e':
|
||
case 'E':
|
||
case 'g':
|
||
case 'G':
|
||
input_line_pointer++;
|
||
floating_constant (expressionP);
|
||
expressionP->X_add_number = -(isupper (c) ? tolower (c) : c);
|
||
break;
|
||
|
||
#ifdef LOCAL_LABELS_DOLLAR
|
||
case '$':
|
||
integer_constant (10, expressionP);
|
||
break;
|
||
#endif
|
||
}
|
||
|
||
break;
|
||
|
||
case '(':
|
||
case '[':
|
||
/* didn't begin with digit & not a name */
|
||
segment = expression (expressionP);
|
||
/* Expression() will pass trailing whitespace */
|
||
if (c == '(' && *input_line_pointer++ != ')' ||
|
||
c == '[' && *input_line_pointer++ != ']')
|
||
{
|
||
as_bad ("Missing ')' assumed");
|
||
input_line_pointer--;
|
||
}
|
||
/* here with input_line_pointer->char after "(...)" */
|
||
return segment;
|
||
|
||
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_op = O_constant;
|
||
expressionP->X_add_number = *input_line_pointer++;
|
||
break;
|
||
|
||
case '+':
|
||
(void) operand (expressionP);
|
||
break;
|
||
|
||
case '~':
|
||
case '-':
|
||
{
|
||
operand (expressionP);
|
||
if (expressionP->X_op == O_constant)
|
||
{
|
||
/* 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. */
|
||
expressionP->X_unsigned = 0;
|
||
}
|
||
else
|
||
expressionP->X_add_number = ~ expressionP->X_add_number;
|
||
}
|
||
else if (expressionP->X_op != O_illegal
|
||
&& expressionP->X_op != O_absent)
|
||
{
|
||
expressionP->X_add_symbol = make_expr_symbol (expressionP);
|
||
if (c == '-')
|
||
expressionP->X_op = O_uminus;
|
||
else
|
||
expressionP->X_op = O_bit_not;
|
||
expressionP->X_add_number = 0;
|
||
}
|
||
else
|
||
as_warn ("Unary operator %c ignored because bad operand follows",
|
||
c);
|
||
}
|
||
break;
|
||
|
||
case '.':
|
||
#ifdef DOLLAR_DOT
|
||
case '$':
|
||
#endif
|
||
if (!is_part_of_name (*input_line_pointer))
|
||
{
|
||
const char *fake;
|
||
|
||
/* JF: '.' is pseudo symbol with value of current location
|
||
in current segment. */
|
||
fake = FAKE_LABEL_NAME;
|
||
symbolP = symbol_new (fake,
|
||
now_seg,
|
||
(valueT) frag_now_fix (),
|
||
frag_now);
|
||
|
||
expressionP->X_op = O_symbol;
|
||
expressionP->X_add_symbol = symbolP;
|
||
expressionP->X_add_number = 0;
|
||
break;
|
||
}
|
||
else
|
||
{
|
||
goto isname;
|
||
}
|
||
case ',':
|
||
case '\n':
|
||
case '\0':
|
||
eol:
|
||
/* can't imagine any other kind of operand */
|
||
expressionP->X_op = O_absent;
|
||
input_line_pointer--;
|
||
md_operand (expressionP);
|
||
break;
|
||
|
||
default:
|
||
if (is_end_of_line[(unsigned char) c])
|
||
goto eol;
|
||
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. */
|
||
segment = S_GET_SEGMENT (symbolP);
|
||
if (segment == absolute_section)
|
||
{
|
||
expressionP->X_op = O_constant;
|
||
expressionP->X_add_number = S_GET_VALUE (symbolP);
|
||
}
|
||
else if (segment == reg_section)
|
||
{
|
||
expressionP->X_op = O_register;
|
||
expressionP->X_add_number = S_GET_VALUE (symbolP);
|
||
}
|
||
else
|
||
{
|
||
expressionP->X_op = O_symbol;
|
||
expressionP->X_add_symbol = symbolP;
|
||
expressionP->X_add_number = 0;
|
||
}
|
||
*input_line_pointer = c;
|
||
}
|
||
else
|
||
{
|
||
as_bad ("Bad expression");
|
||
expressionP->X_op = O_constant;
|
||
expressionP->X_add_number = 0;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* 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 != ' ');
|
||
|
||
/* The PA port needs this information. */
|
||
if (expressionP->X_add_symbol)
|
||
expressionP->X_add_symbol->sy_used = 1;
|
||
|
||
switch (expressionP->X_op)
|
||
{
|
||
default:
|
||
return absolute_section;
|
||
case O_symbol:
|
||
return S_GET_SEGMENT (expressionP->X_add_symbol);
|
||
case O_register:
|
||
return reg_section;
|
||
}
|
||
} /* operand() */
|
||
|
||
/* Internal. Simplify a struct expression for use by expr() */
|
||
|
||
/*
|
||
* In: address of a expressionS.
|
||
* The X_op field of the expressionS may only take certain values.
|
||
* 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_op from O_subtract to O_constant.
|
||
* Unused fields zeroed to help expr().
|
||
*/
|
||
|
||
static void
|
||
clean_up_expression (expressionP)
|
||
expressionS *expressionP;
|
||
{
|
||
switch (expressionP->X_op)
|
||
{
|
||
case O_illegal:
|
||
case O_absent:
|
||
expressionP->X_add_number = 0;
|
||
/* Fall through. */
|
||
case O_big:
|
||
case O_constant:
|
||
case O_register:
|
||
expressionP->X_add_symbol = NULL;
|
||
/* Fall through. */
|
||
case O_symbol:
|
||
case O_uminus:
|
||
case O_bit_not:
|
||
expressionP->X_op_symbol = NULL;
|
||
break;
|
||
case O_subtract:
|
||
if (expressionP->X_op_symbol == expressionP->X_add_symbol
|
||
|| ((expressionP->X_op_symbol->sy_frag
|
||
== expressionP->X_add_symbol->sy_frag)
|
||
&& SEG_NORMAL (S_GET_SEGMENT (expressionP->X_add_symbol))
|
||
&& (S_GET_VALUE (expressionP->X_op_symbol)
|
||
== S_GET_VALUE (expressionP->X_add_symbol))))
|
||
{
|
||
bfd_vma diff = (S_GET_VALUE (expressionP->X_add_symbol)
|
||
- S_GET_VALUE (expressionP->X_op_symbol));
|
||
|
||
expressionP->X_op = O_constant;
|
||
expressionP->X_add_symbol = NULL;
|
||
expressionP->X_op_symbol = NULL;
|
||
expressionP->X_add_number += diff;
|
||
}
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* 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.
|
||
*
|
||
* This returns the segment of the result, which will be
|
||
* absolute_section or the segment of a symbol.
|
||
*/
|
||
|
||
#undef __
|
||
#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 * / % << >>
|
||
* 4 unary - unary ~
|
||
*/
|
||
static const operator_rankT op_rank[] =
|
||
{
|
||
0, /* O_illegal */
|
||
0, /* O_absent */
|
||
0, /* O_constant */
|
||
0, /* O_symbol */
|
||
0, /* O_register */
|
||
0, /* O_bit */
|
||
4, /* O_uminus */
|
||
4, /* O_bit_now */
|
||
3, /* O_multiply */
|
||
3, /* O_divide */
|
||
3, /* O_modulus */
|
||
3, /* O_left_shift */
|
||
3, /* O_right_shift */
|
||
2, /* O_bit_inclusive_or */
|
||
2, /* O_bit_or_not */
|
||
2, /* O_bit_exclusive_or */
|
||
2, /* O_bit_and */
|
||
1, /* O_add */
|
||
1, /* O_subtract */
|
||
};
|
||
|
||
segT
|
||
expr (rank, resultP)
|
||
operator_rankT rank; /* Larger # is higher rank. */
|
||
expressionS *resultP; /* Deliver result here. */
|
||
{
|
||
segT retval;
|
||
expressionS right;
|
||
operatorT op_left;
|
||
char c_left; /* 1st operator character. */
|
||
operatorT op_right;
|
||
char c_right;
|
||
|
||
know (rank >= 0);
|
||
|
||
retval = operand (resultP);
|
||
|
||
know (*input_line_pointer != ' '); /* Operand() gobbles spaces. */
|
||
|
||
c_left = *input_line_pointer; /* Potential operator character. */
|
||
op_left = op_encoding[(unsigned char) c_left];
|
||
while (op_left != O_illegal && op_rank[(int) op_left] > rank)
|
||
{
|
||
segT rightseg;
|
||
|
||
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;
|
||
|
||
rightseg = expr (op_rank[(int) op_left], &right);
|
||
if (right.X_op == O_absent)
|
||
{
|
||
as_warn ("missing operand; zero assumed");
|
||
right.X_op = O_constant;
|
||
right.X_add_number = 0;
|
||
right.X_add_symbol = NULL;
|
||
right.X_op_symbol = NULL;
|
||
}
|
||
|
||
know (*input_line_pointer != ' ');
|
||
|
||
if (retval == undefined_section)
|
||
{
|
||
if (SEG_NORMAL (rightseg))
|
||
retval = rightseg;
|
||
}
|
||
else if (! SEG_NORMAL (retval))
|
||
retval = rightseg;
|
||
else if (SEG_NORMAL (rightseg)
|
||
&& retval != rightseg
|
||
#ifdef DIFF_EXPR_OK
|
||
&& op_left != O_subtract
|
||
#endif
|
||
)
|
||
as_bad ("operation combines symbols in different segments");
|
||
|
||
c_right = *input_line_pointer;
|
||
op_right = op_encoding[(unsigned char) c_right];
|
||
if (*input_line_pointer == c_right && (c_right == '<' || c_right == '>'))
|
||
++input_line_pointer;
|
||
|
||
know (op_right == O_illegal || op_rank[(int) op_right] <= op_rank[(int) op_left]);
|
||
know ((int) op_left >= (int) O_multiply && (int) op_left <= (int) O_subtract);
|
||
|
||
/* input_line_pointer->after right-hand quantity. */
|
||
/* left-hand quantity in resultP */
|
||
/* right-hand quantity in right. */
|
||
/* operator in op_left. */
|
||
|
||
if (resultP->X_op == O_big)
|
||
{
|
||
as_warn ("left operand of %c is a %s; integer 0 assumed",
|
||
c_left, resultP->X_add_number > 0 ? "bignum" : "float");
|
||
resultP->X_op = O_constant;
|
||
resultP->X_add_number = 0;
|
||
resultP->X_add_symbol = NULL;
|
||
resultP->X_op_symbol = NULL;
|
||
}
|
||
if (right.X_op == O_big)
|
||
{
|
||
as_warn ("right operand of %c is a %s; integer 0 assumed",
|
||
c_left, right.X_add_number > 0 ? "bignum" : "float");
|
||
right.X_op = O_constant;
|
||
right.X_add_number = 0;
|
||
right.X_add_symbol = NULL;
|
||
right.X_op_symbol = NULL;
|
||
}
|
||
|
||
/* Optimize common cases. */
|
||
#if 0
|
||
if (op_left == O_add && resultP->X_got_symbol)
|
||
{
|
||
/* XXX - kludge here to accomodate "_GLOBAL_OFFSET_TABLE + (x - y)"
|
||
* expressions: this only works for this special case, the
|
||
* _GLOBAL_OFFSET_TABLE thing *must* be the left operand, the whole
|
||
* expression is given the segment of right expression (always a DIFFERENCE,
|
||
* which should get resolved by fixup_segment())
|
||
*/
|
||
resultP->X_op = right.X_op;
|
||
resultP->X_add_symbol = right.X_add_symbol;
|
||
resultP->X_op_symbol = right.X_op_symbol;
|
||
}
|
||
else
|
||
#endif
|
||
if (op_left == O_add && right.X_op == O_constant)
|
||
{
|
||
/* X + constant. */
|
||
resultP->X_add_number += right.X_add_number;
|
||
}
|
||
/* This case comes up in PIC code. */
|
||
else if (op_left == O_subtract
|
||
&& right.X_op == O_symbol
|
||
&& resultP->X_op == O_symbol
|
||
&& (right.X_add_symbol->sy_frag
|
||
== resultP->X_add_symbol->sy_frag)
|
||
&& SEG_NORMAL (S_GET_SEGMENT (right.X_add_symbol)))
|
||
|
||
{
|
||
resultP->X_add_number += right.X_add_number;
|
||
resultP->X_add_number += (S_GET_VALUE (resultP->X_add_symbol)
|
||
- S_GET_VALUE (right.X_add_symbol));
|
||
resultP->X_op = O_constant;
|
||
resultP->X_add_symbol = 0;
|
||
}
|
||
else if (op_left == O_subtract && right.X_op == O_constant)
|
||
{
|
||
/* X - constant. */
|
||
resultP->X_add_number -= right.X_add_number;
|
||
}
|
||
else if (op_left == O_add && resultP->X_op == O_constant)
|
||
{
|
||
/* Constant + X. */
|
||
resultP->X_op = right.X_op;
|
||
resultP->X_add_symbol = right.X_add_symbol;
|
||
resultP->X_op_symbol = right.X_op_symbol;
|
||
resultP->X_add_number += right.X_add_number;
|
||
retval = rightseg;
|
||
}
|
||
else if (resultP->X_op == O_constant && right.X_op == O_constant)
|
||
{
|
||
/* Constant OP constant. */
|
||
offsetT v = right.X_add_number;
|
||
if (v == 0 && (op_left == O_divide || op_left == O_modulus))
|
||
{
|
||
as_warn ("division by zero");
|
||
v = 1;
|
||
}
|
||
switch (op_left)
|
||
{
|
||
case O_multiply: resultP->X_add_number *= v; break;
|
||
case O_divide: resultP->X_add_number /= v; break;
|
||
case O_modulus: resultP->X_add_number %= v; break;
|
||
case O_left_shift: resultP->X_add_number <<= v; break;
|
||
case O_right_shift: resultP->X_add_number >>= v; break;
|
||
case O_bit_inclusive_or: resultP->X_add_number |= v; break;
|
||
case O_bit_or_not: resultP->X_add_number |= ~v; break;
|
||
case O_bit_exclusive_or: resultP->X_add_number ^= v; break;
|
||
case O_bit_and: resultP->X_add_number &= v; break;
|
||
case O_add: resultP->X_add_number += v; break;
|
||
case O_subtract: resultP->X_add_number -= v; break;
|
||
default: abort ();
|
||
}
|
||
}
|
||
else if (resultP->X_op == O_symbol
|
||
&& right.X_op == O_symbol
|
||
&& (op_left == O_add
|
||
|| op_left == O_subtract
|
||
|| (resultP->X_add_number == 0
|
||
&& right.X_add_number == 0)))
|
||
{
|
||
/* Symbol OP symbol. */
|
||
resultP->X_op = op_left;
|
||
resultP->X_op_symbol = right.X_add_symbol;
|
||
if (op_left == O_add)
|
||
resultP->X_add_number += right.X_add_number;
|
||
else if (op_left == O_subtract)
|
||
resultP->X_add_number -= right.X_add_number;
|
||
}
|
||
else
|
||
{
|
||
/* The general case. */
|
||
resultP->X_add_symbol = make_expr_symbol (resultP);
|
||
resultP->X_op_symbol = make_expr_symbol (&right);
|
||
resultP->X_op = op_left;
|
||
resultP->X_add_number = 0;
|
||
resultP->X_unsigned = 1;
|
||
}
|
||
|
||
op_left = op_right;
|
||
} /* While next operator is >= this rank. */
|
||
|
||
/* The PA port needs this information. */
|
||
if (resultP->X_add_symbol)
|
||
resultP->X_add_symbol->sy_used = 1;
|
||
|
||
return resultP->X_op == O_constant ? absolute_section : retval;
|
||
}
|
||
|
||
/*
|
||
* 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 ()
|
||
{
|
||
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;
|
||
|
||
}
|
||
|
||
/* end of expr.c */
|