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/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2017 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.
*
* ----------------------------------------------------------------------- */
/*
* exprlib.c
*
* Library routines to manipulate expression data types.
*/
#include "nasm.h"
/*
* Return true if the argument is a simple scalar. (Or a far-
* absolute, which counts.)
*/
bool is_simple(const expr *vect)
{
while (vect->type && !vect->value)
vect++;
if (!vect->type)
return true;
if (vect->type != EXPR_SIMPLE)
return false;
do {
vect++;
} while (vect->type && !vect->value);
if (vect->type && vect->type < EXPR_SEGBASE + SEG_ABS)
return false;
return true;
}
/*
* Return true if the argument is a simple scalar, _NOT_ a far-
* absolute.
*/
bool is_really_simple(const expr *vect)
{
while (vect->type && !vect->value)
vect++;
if (!vect->type)
return true;
if (vect->type != EXPR_SIMPLE)
return false;
do {
vect++;
} while (vect->type && !vect->value);
if (vect->type)
return false;
return true;
}
/*
* Return true if the argument is relocatable (i.e. a simple
* scalar, plus at most one segment-base, possibly a subtraction
* of the current segment base, plus possibly a WRT).
*/
bool is_reloc(const expr *vect)
{
bool has_rel = false; /* Has a self-segment-subtract */
bool has_seg = false; /* Has a segment base */
for (; vect->type; vect++) {
if (!vect->value) {
/* skip value-0 terms */
continue;
} else if (vect->type < EXPR_SIMPLE) {
/* false if a register is present */
return false;
} else if (vect->type == EXPR_SIMPLE) {
/* skip over a pure number term... */
continue;
} else if (vect->type == EXPR_WRT) {
/* skip over a WRT term... */
continue;
} else if (vect->type < EXPR_SEGBASE) {
/* other special type -> problem */
return false;
} else if (vect->value == 1) {
if (has_seg)
return false; /* only one segbase allowed */
has_seg = true;
} else if (vect->value == -1) {
if (vect->type != location.segment + EXPR_SEGBASE)
return false; /* can only subtract current segment */
if (has_rel)
return false; /* already is relative */
has_rel = true;
}
}
return true;
}
/*
* Return true if the argument contains an `unknown' part.
*/
bool is_unknown(const expr *vect)
{
while (vect->type && vect->type < EXPR_UNKNOWN)
vect++;
return (vect->type == EXPR_UNKNOWN);
}
/*
* Return true if the argument contains nothing but an `unknown'
* part.
*/
bool is_just_unknown(const expr *vect)
{
while (vect->type && !vect->value)
vect++;
return (vect->type == EXPR_UNKNOWN);
}
/*
* Return the scalar part of a relocatable vector. (Including
* simple scalar vectors - those qualify as relocatable.)
*/
int64_t reloc_value(const expr *vect)
{
while (vect->type && !vect->value)
vect++;
if (!vect->type)
return 0;
if (vect->type == EXPR_SIMPLE)
return vect->value;
else
return 0;
}
/*
* Return the segment number of a relocatable vector, or NO_SEG for
* simple scalars.
*/
int32_t reloc_seg(const expr *vect)
{
for (; vect->type; vect++) {
if (vect->type >= EXPR_SEGBASE && vect->value == 1)
return vect->type - EXPR_SEGBASE;
}
return NO_SEG;
}
/*
* Return the WRT segment number of a relocatable vector, or NO_SEG
* if no WRT part is present.
*/
int32_t reloc_wrt(const expr *vect)
{
while (vect->type && vect->type < EXPR_WRT)
vect++;
if (vect->type == EXPR_WRT) {
return vect->value;
} else
return NO_SEG;
}
/*
* Return true if this expression contains a subtraction of the location
*/
bool is_self_relative(const expr *vect)
{
for (; vect->type; vect++) {
if (vect->type == location.segment + EXPR_SEGBASE && vect->value == -1)
return true;
}
return false;
}
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