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4a5bc1cec672240515d04e15bbcb7b58a50c23b0
nasm/asm/eval.c
H. Peter Anvin bdfa9f952d eval: recognize TOKEN_BRCCONST as integers 
If TOKEN_BRCCONST are used in an expression (including simply wrapping
them in parentheses), then just treat them as integers.  This makes
things like ({dfv=cf}|{dfv=of}) work.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2024-07-27 18:19:35 -07:00

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28 KiB
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/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2024 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ----------------------------------------------------------------------- */
/*
* eval.c expression evaluator for the Netwide Assembler
*/
#include "compiler.h"
#include "nctype.h"
#include "nasm.h"
#include "nasmlib.h"
#include "ilog2.h"
#include "error.h"
#include "eval.h"
#include "labels.h"
#include "floats.h"
#include "assemble.h"
#define TEMPEXPRS_DELTA 128
#define TEMPEXPR_DELTA 8
static scanner scanfunc; /* Address of scanner routine */
static void *scpriv; /* Scanner private pointer */
static expr **tempexprs = NULL;
static int ntempexprs;
static int tempexprs_size = 0;
static expr *tempexpr;
static int ntempexpr;
static int tempexpr_size;
static struct tokenval *tokval; /* The current token */
static int tt; /* The t_type of tokval */
static bool critical;
static int *opflags;
static struct eval_hints *hint;
static int64_t deadman;
/*
* Unimportant cleanup is done to avoid confusing people who are trying
* to debug real memory leaks
*/
void eval_cleanup(void)
{
while (ntempexprs)
nasm_free(tempexprs[--ntempexprs]);
nasm_free(tempexprs);
}
/*
* Construct a temporary expression.
*/
static void begintemp(void)
{
tempexpr = NULL;
tempexpr_size = ntempexpr = 0;
}
static void addtotemp(int32_t type, int64_t value)
{
while (ntempexpr >= tempexpr_size) {
tempexpr_size += TEMPEXPR_DELTA;
tempexpr = nasm_realloc(tempexpr,
tempexpr_size * sizeof(*tempexpr));
}
tempexpr[ntempexpr].type = type;
tempexpr[ntempexpr++].value = value;
}
static expr *finishtemp(void)
{
addtotemp(0L, 0L); /* terminate */
while (ntempexprs >= tempexprs_size) {
tempexprs_size += TEMPEXPRS_DELTA;
tempexprs = nasm_realloc(tempexprs,
tempexprs_size * sizeof(*tempexprs));
}
return tempexprs[ntempexprs++] = tempexpr;
}
/*
* Add two vector datatypes. We have some bizarre behaviour on far-
* absolute segment types: we preserve them during addition _only_
* if one of the segments is a truly pure scalar.
*/
static expr *add_vectors(expr * p, expr * q)
{
int preserve;
preserve = is_really_simple(p) || is_really_simple(q);
begintemp();
while (p->type && q->type &&
p->type < EXPR_SEGBASE + SEG_ABS &&
q->type < EXPR_SEGBASE + SEG_ABS) {
int lasttype;
if (p->type > q->type) {
addtotemp(q->type, q->value);
lasttype = q++->type;
} else if (p->type < q->type) {
addtotemp(p->type, p->value);
lasttype = p++->type;
} else { /* *p and *q have same type */
int64_t sum = p->value + q->value;
if (sum) {
addtotemp(p->type, sum);
if (hint)
hint->type = EAH_SUMMED;
}
lasttype = p->type;
p++, q++;
}
if (lasttype == EXPR_UNKNOWN) {
return finishtemp();
}
}
while (p->type && (preserve || p->type < EXPR_SEGBASE + SEG_ABS)) {
addtotemp(p->type, p->value);
p++;
}
while (q->type && (preserve || q->type < EXPR_SEGBASE + SEG_ABS)) {
addtotemp(q->type, q->value);
q++;
}
return finishtemp();
}
/*
* Multiply a vector by a scalar. Strip far-absolute segment part
* if present.
*
* Explicit treatment of UNKNOWN is not required in this routine,
* since it will silently do the Right Thing anyway.
*
* If `affect_hints' is set, we also change the hint type to
* NOTBASE if a MAKEBASE hint points at a register being
* multiplied. This allows [eax*1+ebx] to hint EBX rather than EAX
* as the base register.
*/
static expr *scalar_mult(expr * vect, int64_t scalar, int affect_hints)
{
expr *p = vect;
while (p->type && p->type < EXPR_SEGBASE + SEG_ABS) {
p->value = scalar * (p->value);
if (hint && hint->type == EAH_MAKEBASE &&
p->type == hint->base && affect_hints)
hint->type = EAH_NOTBASE;
p++;
}
p->type = 0;
return vect;
}
static expr *scalarvect(int64_t scalar)
{
begintemp();
addtotemp(EXPR_SIMPLE, scalar);
return finishtemp();
}
static expr *unknown_expr(void)
{
begintemp();
addtotemp(EXPR_UNKNOWN, 1L);
return finishtemp();
}
/*
* The SEG operator: calculate the segment part of a relocatable
* value. Return NULL, as usual, if an error occurs. Report the
* error too.
*/
static expr *segment_part(expr * e)
{
int32_t seg;
if (is_unknown(e))
return unknown_expr();
if (!is_reloc(e)) {
nasm_nonfatal("cannot apply SEG to a non-relocatable value");
return NULL;
}
seg = reloc_seg(e);
if (seg == NO_SEG) {
nasm_nonfatal("cannot apply SEG to a non-relocatable value");
return NULL;
} else if (seg & SEG_ABS) {
return scalarvect(seg & ~SEG_ABS);
} else if (seg & 1) {
nasm_nonfatal("SEG applied to something which"
" is already a segment base");
return NULL;
} else {
int32_t base = ofmt->segbase(seg + 1);
begintemp();
addtotemp((base == NO_SEG ? EXPR_UNKNOWN : EXPR_SEGBASE + base),
1L);
return finishtemp();
}
}
/*
* Recursive-descent parser. Called with a single boolean operand,
* which is true if the evaluation is critical (i.e. unresolved
* symbols are an error condition). Must update the global `tt' to
* reflect the token after the parsed string. May return NULL.
*
* evaluate() should report its own errors: on return it is assumed
* that if NULL has been returned, the error has already been
* reported.
*
*/
/*
* Wrapper function around the scanner
*/
static int scan(void)
{
return tt = scanfunc(scpriv, tokval);
}
/*
* Grammar parsed is:
*
* expr : bexpr [ WRT expr6 ]
* bexpr : cexpr
* cexpr : rexp0 [ {?} bexpr {:} cexpr ]
* rexp0 : rexp1 [ {||} rexp1...]
* rexp1 : rexp2 [ {^^} rexp2...]
* rexp2 : rexp3 [ {&&} rexp3...]
* rexp3 : expr0 [ {=,==,<>,!=,<,>,<=,>=,<=>} expr0... ]
* expr0 : expr1 [ {|} expr1...]
* expr1 : expr2 [ {^} expr2...]
* expr2 : expr3 [ {&} expr3...]
* expr3 : expr4 [ {<<,>>,<<<,>>>} expr4...]
* expr4 : expr5 [ {+,-} expr5...]
* expr5 : expr6 [ {*,/,%,//,%%} expr6...]
* expr6 : { ~,+,-,IFUNC,SEG } expr6
* | (bexpr)
* | symbol
* | $
* | number
*/
static expr *cexpr(void);
static expr *rexp0(void), *rexp1(void), *rexp2(void), *rexp3(void);
static expr *expr0(void), *expr1(void), *expr2(void), *expr3(void);
static expr *expr4(void), *expr5(void), *expr6(void);
/* This inline is a placeholder for the root of the basic expression */
static inline expr *bexpr(void)
{
return cexpr();
}
static expr *cexpr(void)
{
expr *e, *f, *g;
e = rexp0();
if (!e)
return NULL;
if (tt == TOKEN_QMARK) {
scan();
f = bexpr();
if (!f)
return NULL;
if (tt != ':') {
nasm_nonfatal("`?' without matching `:'");
return NULL;
}
scan();
g = cexpr();
if (!g)
return NULL;
if (is_simple(e)) {
e = reloc_value(e) ? f : g;
} else if (is_just_unknown(e)) {
e = unknown_expr();
} else {
nasm_nonfatal("the left-hand side of `?' must be "
"a scalar value");
}
}
return e;
}
static expr *rexp0(void)
{
expr *e, *f;
e = rexp1();
if (!e)
return NULL;
while (tt == TOKEN_DBL_OR) {
scan();
f = rexp1();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`|' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int64_t)(reloc_value(e) || reloc_value(f)));
}
return e;
}
static expr *rexp1(void)
{
expr *e, *f;
e = rexp2();
if (!e)
return NULL;
while (tt == TOKEN_DBL_XOR) {
scan();
f = rexp2();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`^' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int64_t)(!reloc_value(e) ^ !reloc_value(f)));
}
return e;
}
static expr *rexp2(void)
{
expr *e, *f;
e = rexp3();
if (!e)
return NULL;
while (tt == TOKEN_DBL_AND) {
scan();
f = rexp3();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`&' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int64_t)(reloc_value(e) && reloc_value(f)));
}
return e;
}
static expr *rexp3(void)
{
expr *e, *f;
int64_t v;
e = expr0();
if (!e)
return NULL;
while (tt == TOKEN_EQ || tt == TOKEN_LT || tt == TOKEN_GT ||
tt == TOKEN_NE || tt == TOKEN_LE || tt == TOKEN_GE ||
tt == TOKEN_LEG) {
int tto = tt;
scan();
f = expr0();
if (!f)
return NULL;
e = add_vectors(e, scalar_mult(f, -1L, false));
switch (tto) {
case TOKEN_EQ:
case TOKEN_NE:
if (is_unknown(e))
v = -1; /* means unknown */
else if (!is_really_simple(e) || reloc_value(e) != 0)
v = (tto == TOKEN_NE); /* unequal, so return true if NE */
else
v = (tto == TOKEN_EQ); /* equal, so return true if EQ */
break;
default:
if (is_unknown(e))
v = -1; /* means unknown */
else if (!is_really_simple(e)) {
nasm_nonfatal("`%s': operands differ by a non-scalar",
(tto == TOKEN_LE ? "<=" :
tto == TOKEN_LT ? "<" :
tto == TOKEN_GE ? ">=" :
tto == TOKEN_GT ? ">" :
tto == TOKEN_LEG ? "<=>" :
"<internal error>"));
v = 0; /* must set it to _something_ */
} else {
int64_t vv = reloc_value(e);
if (tto == TOKEN_LEG)
v = (vv < 0) ? -1 : (vv > 0) ? 1 : 0;
else if (vv == 0)
v = (tto == TOKEN_LE || tto == TOKEN_GE);
else if (vv > 0)
v = (tto == TOKEN_GE || tto == TOKEN_GT);
else /* vv < 0 */
v = (tto == TOKEN_LE || tto == TOKEN_LT);
}
break;
}
if (v == -1)
e = unknown_expr();
else
e = scalarvect(v);
}
return e;
}
static expr *expr0(void)
{
expr *e, *f;
e = expr1();
if (!e)
return NULL;
while (tt == '|') {
scan();
f = expr1();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`|' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(reloc_value(e) | reloc_value(f));
}
return e;
}
static expr *expr1(void)
{
expr *e, *f;
e = expr2();
if (!e)
return NULL;
while (tt == '^') {
scan();
f = expr2();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`^' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(reloc_value(e) ^ reloc_value(f));
}
return e;
}
static expr *expr2(void)
{
expr *e, *f;
e = expr3();
if (!e)
return NULL;
while (tt == '&') {
scan();
f = expr3();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("`&' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(reloc_value(e) & reloc_value(f));
}
return e;
}
static expr *expr3(void)
{
expr *e, *f;
e = expr4();
if (!e)
return NULL;
while (tt == TOKEN_SHL || tt == TOKEN_SHR || tt == TOKEN_SAR) {
int tto = tt;
scan();
f = expr4();
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
nasm_nonfatal("shift operator may only be applied to"
" scalar values");
} else if (is_just_unknown(e) || is_just_unknown(f)) {
e = unknown_expr();
} else {
switch (tto) {
case TOKEN_SHL:
e = scalarvect(reloc_value(e) << reloc_value(f));
break;
case TOKEN_SHR:
e = scalarvect(((uint64_t)reloc_value(e)) >>
reloc_value(f));
break;
case TOKEN_SAR:
e = scalarvect(((int64_t)reloc_value(e)) >>
reloc_value(f));
break;
}
}
}
return e;
}
static expr *expr4(void)
{
expr *e, *f;
e = expr5();
if (!e)
return NULL;
while (tt == '+' || tt == '-') {
int tto = tt;
scan();
f = expr5();
if (!f)
return NULL;
switch (tto) {
case '+':
e = add_vectors(e, f);
break;
case '-':
e = add_vectors(e, scalar_mult(f, -1L, false));
break;
}
}
return e;
}
static expr *expr5(void)
{
expr *e, *f;
e = expr6();
if (!e)
return NULL;
while (tt == '*' || tt == '/' || tt == '%' ||
tt == TOKEN_SDIV || tt == TOKEN_SMOD) {
int tto = tt;
scan();
f = expr6();
if (!f)
return NULL;
if (tto != '*' && (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f)))) {
nasm_nonfatal("division operator may only be applied to"
" scalar values");
return NULL;
}
if (tto != '*' && !is_just_unknown(f) && reloc_value(f) == 0) {
nasm_nonfatal("division by zero");
return NULL;
}
switch (tto) {
case '*':
if (is_simple(e))
e = scalar_mult(f, reloc_value(e), true);
else if (is_simple(f))
e = scalar_mult(e, reloc_value(f), true);
else if (is_just_unknown(e) && is_just_unknown(f))
e = unknown_expr();
else {
nasm_nonfatal("unable to multiply two "
"non-scalar objects");
return NULL;
}
break;
case '/':
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((uint64_t)reloc_value(e)) /
((uint64_t)reloc_value(f)));
break;
case '%':
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((uint64_t)reloc_value(e)) %
((uint64_t)reloc_value(f)));
break;
case TOKEN_SDIV:
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((int64_t)reloc_value(e)) /
((int64_t)reloc_value(f)));
break;
case TOKEN_SMOD:
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((int64_t)reloc_value(e)) %
((int64_t)reloc_value(f)));
break;
}
}
return e;
}
static expr *eval_floatize(enum floatize type)
{
uint8_t result[16], *p; /* Up to 128 bits */
int sign = 1;
int64_t val;
size_t len;
int i;
const struct ieee_format *fmt;
fmt = &fp_formats[type];
scan();
if (tt != '(') {
nasm_nonfatal("expecting `('");
return NULL;
}
scan();
if (tt == '-' || tt == '+') {
sign = (tt == '-') ? -1 : 1;
scan();
}
if (tt != TOKEN_FLOAT) {
nasm_nonfatal("expecting floating-point number");
return NULL;
}
if (!float_const(tokval->t_charptr, sign, result, type))
return NULL;
scan();
if (tt != ')') {
nasm_nonfatal("expecting `)'");
return NULL;
}
len = fmt->bytes - fmt->offset;
if (len > 8)
len = 8; /* Max 64 bits */
p = result + len + fmt->offset;
val = 0;
for (i = len; i; i--) {
p--;
val = (val << 8) + *p;
}
begintemp();
addtotemp(EXPR_SIMPLE, val);
scan();
return finishtemp();
}
static expr *eval_strfunc(enum strfunc type, const char *name)
{
char *string;
size_t string_len;
int64_t val;
bool parens, rn_warn;
parens = false;
scan();
if (tt == '(') {
parens = true;
scan();
}
if (tt != TOKEN_STR) {
nasm_nonfatal("expecting string as argument to %s", name);
return NULL;
}
string_len = string_transform(tokval->t_charptr, tokval->t_inttwo,
&string, type);
if (string_len == (size_t)-1) {
nasm_nonfatal("invalid input string to %s", name);
return NULL;
}
val = readstrnum(string, string_len, &rn_warn);
if (parens) {
scan();
if (tt != ')') {
nasm_nonfatal("expecting `)'");
return NULL;
}
}
if (rn_warn)
nasm_warn(WARN_OTHER, "character constant too long");
begintemp();
addtotemp(EXPR_SIMPLE, val);
scan();
return finishtemp();
}
static int64_t eval_ifunc(int64_t val, enum ifunc func)
{
uint64_t uval = (uint64_t)val;
int64_t rv;
switch (func) {
case IFUNC_ILOG2E:
case IFUNC_ILOG2W:
if (!is_power2(uval))
nasm_error((func == IFUNC_ILOG2E) ? ERR_NONFATAL : ERR_WARNING|WARN_OTHER,
"ilog2 argument is not a power of two");
/* fall through */
case IFUNC_ILOG2F:
rv = ilog2_64(uval);
break;
case IFUNC_ILOG2C:
rv = (uval < 2) ? 0 : ilog2_64(uval-1) + 1;
break;
default:
nasm_panic("invalid IFUNC token %d", func);
rv = 0;
break;
}
return rv;
}
static expr *expr6(void)
{
int32_t type;
expr *e;
int32_t label_seg;
int64_t label_ofs;
int64_t tmpval;
bool rn_warn;
const char *scope;
if (++deadman > nasm_limit[LIMIT_EVAL]) {
nasm_nonfatal("expression too long");
return NULL;
}
switch (tt) {
case '-':
scan();
e = expr6();
if (!e)
return NULL;
return scalar_mult(e, -1L, false);
case '+':
scan();
return expr6();
case '~':
scan();
e = expr6();
if (!e)
return NULL;
if (is_just_unknown(e))
return unknown_expr();
else if (!is_simple(e)) {
nasm_nonfatal("`~' operator may only be applied to"
" scalar values");
return NULL;
}
return scalarvect(~reloc_value(e));
case '!':
scan();
e = expr6();
if (!e)
return NULL;
if (is_just_unknown(e))
return unknown_expr();
else if (!is_simple(e)) {
nasm_nonfatal("`!' operator may only be applied to"
" scalar values");
return NULL;
}
return scalarvect(!reloc_value(e));
case TOKEN_IFUNC:
{
enum ifunc func = tokval->t_integer;
scan();
e = expr6();
if (!e)
return NULL;
if (is_just_unknown(e))
return unknown_expr();
else if (!is_simple(e)) {
nasm_nonfatal("function may only be applied to"
" scalar values");
return NULL;
}
return scalarvect(eval_ifunc(reloc_value(e), func));
}
case TOKEN_SEG:
scan();
e = expr6();
if (!e)
return NULL;
e = segment_part(e);
if (!e)
return NULL;
if (is_unknown(e) && critical) {
nasm_nonfatal("unable to determine segment base");
return NULL;
}
return e;
case TOKEN_FLOATIZE:
return eval_floatize(tokval->t_integer);
case TOKEN_STRFUNC:
return eval_strfunc(tokval->t_integer, tokval->t_charptr);
case '(':
scan();
e = bexpr();
if (!e)
return NULL;
if (tt != ')') {
nasm_nonfatal("expecting `)'");
return NULL;
}
scan();
return e;
case TOKEN_NUM:
case TOKEN_BRCCONST:
case TOKEN_STR:
case TOKEN_REG:
case TOKEN_ID:
case TOKEN_INSN: /* Opcodes that occur here are really labels */
case TOKEN_HERE:
case TOKEN_BASE:
case TOKEN_DECORATOR:
begintemp();
switch (tt) {
case TOKEN_NUM:
case TOKEN_BRCCONST:
addtotemp(EXPR_SIMPLE, tokval->t_integer);
break;
case TOKEN_STR:
tmpval = readstrnum(tokval->t_charptr, tokval->t_inttwo, &rn_warn);
if (rn_warn)
nasm_warn(WARN_OTHER, "character constant too long");
addtotemp(EXPR_SIMPLE, tmpval);
break;
case TOKEN_REG:
addtotemp(tokval->t_integer, 1L);
if (hint && hint->type == EAH_NOHINT)
hint->base = tokval->t_integer, hint->type = EAH_MAKEBASE;
break;
case TOKEN_ID:
case TOKEN_INSN:
case TOKEN_HERE:
case TOKEN_BASE:
/*
* If !location.known, this indicates that no
* symbol, Here or Base references are valid because we
* are in preprocess-only mode.
*/
if (!location.known) {
nasm_nonfatal("%s not supported in preprocess-only mode",
(tt == TOKEN_HERE ? "`$'" :
tt == TOKEN_BASE ? "`$$'" :
"symbol references"));
addtotemp(EXPR_UNKNOWN, 1L);
break;
}
type = EXPR_SIMPLE; /* might get overridden by UNKNOWN */
if (tt == TOKEN_BASE) {
label_seg = in_absolute ? absolute.segment : location.segment;
label_ofs = 0;
} else if (tt == TOKEN_HERE) {
label_seg = in_absolute ? absolute.segment : location.segment;
label_ofs = in_absolute ? absolute.offset : location.offset;
} else {
enum label_type ltype;
ltype = lookup_label(tokval->t_charptr, &label_seg, &label_ofs);
if (ltype == LBL_none) {
scope = local_scope(tokval->t_charptr);
if (critical) {
nasm_nonfatal("symbol `%s%s' not defined%s",
scope,tokval->t_charptr,
pass_first() ? " before use" : "");
return NULL;
}
if (opflags)
*opflags |= OPFLAG_FORWARD;
type = EXPR_UNKNOWN;
label_seg = NO_SEG;
label_ofs = 1;
} else if (is_extern(ltype)) {
if (opflags)
*opflags |= OPFLAG_EXTERN;
}
}
addtotemp(type, label_ofs);
if (label_seg != NO_SEG)
addtotemp(EXPR_SEGBASE + label_seg, 1L);
break;
case TOKEN_DECORATOR:
addtotemp(EXPR_RDSAE, tokval->t_integer);
break;
}
scan();
return finishtemp();
default:
nasm_nonfatal("expression syntax error");
return NULL;
}
}
expr *evaluate(scanner sc, void *scprivate, struct tokenval *tv,
int *fwref, bool crit, struct eval_hints *hints)
{
expr *e;
expr *f = NULL;
deadman = 0;
hint = hints;
if (hint)
hint->type = EAH_NOHINT;
critical = crit;
scanfunc = sc;
scpriv = scprivate;
tokval = tv;
opflags = fwref;
while (ntempexprs) /* initialize temporary storage */
nasm_free(tempexprs[--ntempexprs]);
tt = tokval->t_type;
if (tt == TOKEN_INVALID)
scan();
e = bexpr();
if (!e)
return NULL;
if (tt == TOKEN_WRT) {
scan(); /* eat the WRT */
f = expr6();
if (!f)
return NULL;
}
e = scalar_mult(e, 1L, false); /* strip far-absolute segment part */
if (f) {
expr *g;
if (is_just_unknown(f))
g = unknown_expr();
else {
int64_t value;
begintemp();
if (!is_reloc(f)) {
nasm_nonfatal("invalid right-hand operand to WRT");
return NULL;
}
value = reloc_seg(f);
if (value == NO_SEG)
value = reloc_value(f) | SEG_ABS;
else if (!(value & SEG_ABS) && !(value % 2) && critical) {
nasm_nonfatal("invalid right-hand operand to WRT");
return NULL;
}
addtotemp(EXPR_WRT, value);
g = finishtemp();
}
e = add_vectors(e, g);
}
return e;
}
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