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nasm/eval.c
H. Peter Anvin fe501957c0 Portability fixes 
Concentrate compiler dependencies to compiler.h; make sure compiler.h
is included first in every .c file (since some prototypes may depend
on the presence of feature request macros.)

Actually use the conditional inclusion of various functions (totally
broken in previous releases.)
2007-10-02 21:53:51 -07:00

890 lines
24 KiB
C
Raw Blame History

/* eval.c expression evaluator for the Netwide Assembler
*
* The Netwide Assembler is copyright (C) 1996 Simon Tatham and
* Julian Hall. All rights reserved. The software is
* redistributable under the licence given in the file "Licence"
* distributed in the NASM archive.
*
* initial version 27/iii/95 by Simon Tatham
*/
#include "compiler.h"
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <ctype.h>
#include <inttypes.h>
#include "nasm.h"
#include "nasmlib.h"
#include "eval.h"
#include "labels.h"
#include "float.h"
#define TEMPEXPRS_DELTA 128
#define TEMPEXPR_DELTA 8
static scanner scan; /* Address of scanner routine */
static efunc error; /* Address of error reporting routine */
static lfunc labelfunc; /* Address of label routine */
static struct ofmt *outfmt; /* Structure of addresses of output routines */
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 i; /* The t_type of tokval */
static void *scpriv;
static loc_t *location; /* Pointer to current line's segment,offset */
static int *opflags;
static struct eval_hints *hint;
extern int in_abs_seg; /* ABSOLUTE segment flag */
extern int32_t abs_seg; /* ABSOLUTE segment */
extern int32_t abs_offset; /* ABSOLUTE segment offset */
/*
* 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 */
int32_t sum = p->value + q->value;
if (sum)
addtotemp(p->type, sum);
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, int32_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(int32_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)) {
error(ERR_NONFATAL, "cannot apply SEG to a non-relocatable value");
return NULL;
}
seg = reloc_seg(e);
if (seg == NO_SEG) {
error(ERR_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) {
error(ERR_NONFATAL, "SEG applied to something which"
" is already a segment base");
return NULL;
} else {
int32_t base = outfmt->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 `i' 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.
*/
/*
* Grammar parsed is:
*
* expr : bexpr [ WRT expr6 ]
* bexpr : rexp0 or expr0 depending on relative-mode setting
* 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 : { ~,+,-,SEG } expr6
* | (bexpr)
* | symbol
* | $
* | number
*/
static expr *rexp0(int), *rexp1(int), *rexp2(int), *rexp3(int);
static expr *expr0(int), *expr1(int), *expr2(int), *expr3(int);
static expr *expr4(int), *expr5(int), *expr6(int);
static expr *(*bexpr) (int);
static expr *rexp0(int critical)
{
expr *e, *f;
e = rexp1(critical);
if (!e)
return NULL;
while (i == TOKEN_DBL_OR) {
i = scan(scpriv, tokval);
f = rexp1(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_NONFATAL, "`|' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int32_t)(reloc_value(e) || reloc_value(f)));
}
return e;
}
static expr *rexp1(int critical)
{
expr *e, *f;
e = rexp2(critical);
if (!e)
return NULL;
while (i == TOKEN_DBL_XOR) {
i = scan(scpriv, tokval);
f = rexp2(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_NONFATAL, "`^' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int32_t)(!reloc_value(e) ^ !reloc_value(f)));
}
return e;
}
static expr *rexp2(int critical)
{
expr *e, *f;
e = rexp3(critical);
if (!e)
return NULL;
while (i == TOKEN_DBL_AND) {
i = scan(scpriv, tokval);
f = rexp3(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_NONFATAL, "`&' operator may only be applied to"
" scalar values");
}
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect((int32_t)(reloc_value(e) && reloc_value(f)));
}
return e;
}
static expr *rexp3(int critical)
{
expr *e, *f;
int32_t v;
e = expr0(critical);
if (!e)
return NULL;
while (i == TOKEN_EQ || i == TOKEN_LT || i == TOKEN_GT ||
i == TOKEN_NE || i == TOKEN_LE || i == TOKEN_GE) {
int j = i;
i = scan(scpriv, tokval);
f = expr0(critical);
if (!f)
return NULL;
e = add_vectors(e, scalar_mult(f, -1L, FALSE));
switch (j) {
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 = (j == TOKEN_NE); /* unequal, so return TRUE if NE */
else
v = (j == TOKEN_EQ); /* equal, so return TRUE if EQ */
break;
default:
if (is_unknown(e))
v = -1; /* means unknown */
else if (!is_really_simple(e)) {
error(ERR_NONFATAL,
"`%s': operands differ by a non-scalar",
(j == TOKEN_LE ? "<=" : j == TOKEN_LT ? "<" : j ==
TOKEN_GE ? ">=" : ">"));
v = 0; /* must set it to _something_ */
} else {
int vv = reloc_value(e);
if (vv == 0)
v = (j == TOKEN_LE || j == TOKEN_GE);
else if (vv > 0)
v = (j == TOKEN_GE || j == TOKEN_GT);
else /* vv < 0 */
v = (j == TOKEN_LE || j == TOKEN_LT);
}
break;
}
if (v == -1)
e = unknown_expr();
else
e = scalarvect(v);
}
return e;
}
static expr *expr0(int critical)
{
expr *e, *f;
e = expr1(critical);
if (!e)
return NULL;
while (i == '|') {
i = scan(scpriv, tokval);
f = expr1(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_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(int critical)
{
expr *e, *f;
e = expr2(critical);
if (!e)
return NULL;
while (i == '^') {
i = scan(scpriv, tokval);
f = expr2(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_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(int critical)
{
expr *e, *f;
e = expr3(critical);
if (!e)
return NULL;
while (i == '&') {
i = scan(scpriv, tokval);
f = expr3(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_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(int critical)
{
expr *e, *f;
e = expr4(critical);
if (!e)
return NULL;
while (i == TOKEN_SHL || i == TOKEN_SHR) {
int j = i;
i = scan(scpriv, tokval);
f = expr4(critical);
if (!f)
return NULL;
if (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f))) {
error(ERR_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 (j) {
case TOKEN_SHL:
e = scalarvect(reloc_value(e) << reloc_value(f));
break;
case TOKEN_SHR:
e = scalarvect(((uint32_t)reloc_value(e)) >>
reloc_value(f));
break;
}
}
return e;
}
static expr *expr4(int critical)
{
expr *e, *f;
e = expr5(critical);
if (!e)
return NULL;
while (i == '+' || i == '-') {
int j = i;
i = scan(scpriv, tokval);
f = expr5(critical);
if (!f)
return NULL;
switch (j) {
case '+':
e = add_vectors(e, f);
break;
case '-':
e = add_vectors(e, scalar_mult(f, -1L, FALSE));
break;
}
}
return e;
}
static expr *expr5(int critical)
{
expr *e, *f;
e = expr6(critical);
if (!e)
return NULL;
while (i == '*' || i == '/' || i == '%' ||
i == TOKEN_SDIV || i == TOKEN_SMOD) {
int j = i;
i = scan(scpriv, tokval);
f = expr6(critical);
if (!f)
return NULL;
if (j != '*' && (!(is_simple(e) || is_just_unknown(e)) ||
!(is_simple(f) || is_just_unknown(f)))) {
error(ERR_NONFATAL, "division operator may only be applied to"
" scalar values");
return NULL;
}
if (j != '*' && !is_unknown(f) && reloc_value(f) == 0) {
error(ERR_NONFATAL, "division by zero");
return NULL;
}
switch (j) {
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 {
error(ERR_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(((uint32_t)reloc_value(e)) /
((uint32_t)reloc_value(f)));
break;
case '%':
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((uint32_t)reloc_value(e)) %
((uint32_t)reloc_value(f)));
break;
case TOKEN_SDIV:
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((int32_t)reloc_value(e)) /
((int32_t)reloc_value(f)));
break;
case TOKEN_SMOD:
if (is_just_unknown(e) || is_just_unknown(f))
e = unknown_expr();
else
e = scalarvect(((int32_t)reloc_value(e)) %
((int32_t)reloc_value(f)));
break;
}
}
return e;
}
static expr *eval_floatize(enum floatize type)
{
uint8_t result[16], *p; /* Up to 128 bits */
static const struct {
int bytes, start, len;
} formats[] = {
{ 2, 0, 2 }, /* FLOAT_16 */
{ 4, 0, 4 }, /* FLOAT_32 */
{ 8, 0, 8 }, /* FLOAT_64 */
{ 10, 0, 8 }, /* FLOAT_80M */
{ 10, 8, 2 }, /* FLOAT_80E */
{ 16, 0, 8 }, /* FLOAT_128L */
{ 16, 8, 8 }, /* FLOAT_128H */
};
int sign = 1;
int64_t val;
int j;
i = scan(scpriv, tokval);
if (i != '(') {
error(ERR_NONFATAL, "expecting `('");
return NULL;
}
i = scan(scpriv, tokval);
if (i == '-' || i == '+') {
sign = (i == '-') ? -1 : 1;
i = scan(scpriv, tokval);
}
if (i != TOKEN_FLOAT) {
error(ERR_NONFATAL, "expecting floating-point number");
return NULL;
}
if (!float_const(tokval->t_charptr, sign, result,
formats[type].bytes, error))
return NULL;
i = scan(scpriv, tokval);
if (i != ')') {
error(ERR_NONFATAL, "expecting `)'");
return NULL;
}
p = result+formats[type].start+formats[type].len;
val = 0;
for (j = formats[type].len; j; j--) {
p--;
val = (val << 8) + *p;
}
begintemp();
addtotemp(EXPR_SIMPLE, val);
i = scan(scpriv, tokval);
return finishtemp();
}
static expr *expr6(int critical)
{
int32_t type;
expr *e;
int32_t label_seg, label_ofs;
switch (i) {
case '-':
i = scan(scpriv, tokval);
e = expr6(critical);
if (!e)
return NULL;
return scalar_mult(e, -1L, FALSE);
case '+':
i = scan(scpriv, tokval);
return expr6(critical);
case '~':
i = scan(scpriv, tokval);
e = expr6(critical);
if (!e)
return NULL;
if (is_just_unknown(e))
return unknown_expr();
else if (!is_simple(e)) {
error(ERR_NONFATAL, "`~' operator may only be applied to"
" scalar values");
return NULL;
}
return scalarvect(~reloc_value(e));
case '!':
i = scan(scpriv, tokval);
e = expr6(critical);
if (!e)
return NULL;
if (is_just_unknown(e))
return unknown_expr();
else if (!is_simple(e)) {
error(ERR_NONFATAL, "`!' operator may only be applied to"
" scalar values");
return NULL;
}
return scalarvect(!reloc_value(e));
case TOKEN_SEG:
i = scan(scpriv, tokval);
e = expr6(critical);
if (!e)
return NULL;
e = segment_part(e);
if (!e)
return NULL;
if (is_unknown(e) && critical) {
error(ERR_NONFATAL, "unable to determine segment base");
return NULL;
}
return e;
case TOKEN_FLOATIZE:
return eval_floatize(tokval->t_integer);
case '(':
i = scan(scpriv, tokval);
e = bexpr(critical);
if (!e)
return NULL;
if (i != ')') {
error(ERR_NONFATAL, "expecting `)'");
return NULL;
}
i = scan(scpriv, tokval);
return e;
case TOKEN_NUM:
case TOKEN_REG:
case TOKEN_ID:
case TOKEN_HERE:
case TOKEN_BASE:
begintemp();
switch (i) {
case TOKEN_NUM:
addtotemp(EXPR_SIMPLE, tokval->t_integer);
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_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) {
error(ERR_NONFATAL,
"%s not supported in preprocess-only mode",
(i == TOKEN_ID ? "symbol references" :
i == TOKEN_HERE ? "`$'" : "`$$'"));
addtotemp(EXPR_UNKNOWN, 1L);
break;
}
type = EXPR_SIMPLE; /* might get overridden by UNKNOWN */
if (i == TOKEN_BASE) {
label_seg = in_abs_seg ? abs_seg : location->segment;
label_ofs = 0;
} else if (i == TOKEN_HERE) {
label_seg = in_abs_seg ? abs_seg : location->segment;
label_ofs = in_abs_seg ? abs_offset : location->offset;
} else {
if (!labelfunc(tokval->t_charptr, &label_seg, &label_ofs)) {
if (critical == 2) {
error(ERR_NONFATAL, "symbol `%s' undefined",
tokval->t_charptr);
return NULL;
} else if (critical == 1) {
error(ERR_NONFATAL,
"symbol `%s' not defined before use",
tokval->t_charptr);
return NULL;
} else {
if (opflags)
*opflags |= 1;
type = EXPR_UNKNOWN;
label_seg = NO_SEG;
label_ofs = 1;
}
}
if (opflags && is_extern(tokval->t_charptr))
*opflags |= OPFLAG_EXTERN;
}
addtotemp(type, label_ofs);
if (label_seg != NO_SEG)
addtotemp(EXPR_SEGBASE + label_seg, 1L);
break;
}
i = scan(scpriv, tokval);
return finishtemp();
default:
error(ERR_NONFATAL, "expression syntax error");
return NULL;
}
}
void eval_global_info(struct ofmt *output, lfunc lookup_label,
loc_t * locp)
{
outfmt = output;
labelfunc = lookup_label;
location = locp;
}
expr *evaluate(scanner sc, void *scprivate, struct tokenval *tv,
int *fwref, int critical, efunc report_error,
struct eval_hints *hints)
{
expr *e;
expr *f = NULL;
hint = hints;
if (hint)
hint->type = EAH_NOHINT;
if (critical & CRITICAL) {
critical &= ~CRITICAL;
bexpr = rexp0;
} else
bexpr = expr0;
scan = sc;
scpriv = scprivate;
tokval = tv;
error = report_error;
opflags = fwref;
if (tokval->t_type == TOKEN_INVALID)
i = scan(scpriv, tokval);
else
i = tokval->t_type;
while (ntempexprs) /* initialize temporary storage */
nasm_free(tempexprs[--ntempexprs]);
e = bexpr(critical);
if (!e)
return NULL;
if (i == TOKEN_WRT) {
i = scan(scpriv, tokval); /* eat the WRT */
f = expr6(critical);
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)) {
error(ERR_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) {
error(ERR_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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