+/* 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. */
+
+/*
+ * 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 <ctype.h>
+#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;
+\f
+/*
+ * 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.
+ *
+ */
+\f
+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])<maxdig; c = * input_line_pointer ++)
+ {
+ number = number * radix + digit;
+ }
+ /* C contains character after number. */
+ /* Input_line_pointer -> 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 */
+\f
+/* 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;
+ }
+}
+\f
+/*
+ * 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() */
+\f
+/* 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 };
+\f
+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;
+ }
+\f
+ 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);
+}
+\f
+/*
+ * 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 */
projects / unix-history / commitdiff