nasm/output/legacy.c
H. Peter Anvin 21c977e717 output/legacy: when converting OUT_SEGMENT, clear the offset
Legacy backends like obj/omf may depend on the offset being zero if
not in use.

Reported-by: Bernd Boeckmann <bernd-freedos@boeckmann.io>
Reported-by: Vladimir Chebotarev <vladimir.chebotarev@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2023-10-16 17:19:45 -07:00

126 lines
4.1 KiB
C

/* ----------------------------------------------------------------------- *
*
* Copyright 2016-2023 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.
*
* ----------------------------------------------------------------------- */
/*
* output/legacy.c
*
* Mangle a struct out_data to match the rather bizarre legacy
* backend interface.
*
* The "data" parameter for the output function points to a "int64_t",
* containing the address of the target in question, unless the type is
* OUT_RAWDATA, in which case it points to an "uint8_t"
* array.
*
* Exceptions are OUT_RELxADR, which denote an x-byte relocation
* which will be a relative jump. For this we need to know the
* distance in bytes from the start of the relocated record until
* the end of the containing instruction. _This_ is what is stored
* in the size part of the parameter, in this case.
*
* Also OUT_RESERVE denotes reservation of N bytes of BSS space,
* and the contents of the "data" parameter is irrelevant.
*/
#include "nasm.h"
#include "outlib.h"
void nasm_do_legacy_output(const struct out_data *data)
{
const void *dptr = data->data;
enum out_type type = data->type;
int32_t tsegment = data->tsegment;
int32_t twrt = data->twrt;
uint64_t size = data->size;
switch (data->type) {
case OUT_RELADDR:
switch (data->size) {
case 1:
type = OUT_REL1ADR;
break;
case 2:
type = OUT_REL2ADR;
break;
case 4:
type = OUT_REL4ADR;
break;
case 8:
type = OUT_REL8ADR;
break;
default:
panic();
break;
}
dptr = &data->toffset;
size = data->relbase - data->offset;
break;
case OUT_SEGMENT:
type = OUT_ADDRESS;
if (tsegment != NO_SEG && tsegment < SEG_ABS)
tsegment |= 1;
dptr = zero_buffer;
size = data->size;
break;
case OUT_ADDRESS:
dptr = &data->toffset;
size = (data->flags & OUT_SIGNED) ? -data->size : data->size;
break;
case OUT_RAWDATA:
case OUT_RESERVE:
tsegment = twrt = NO_SEG;
break;
case OUT_ZERODATA:
tsegment = twrt = NO_SEG;
type = OUT_RAWDATA;
dptr = zero_buffer;
while (size > ZERO_BUF_SIZE) {
ofmt->legacy_output(data->segment, dptr, type,
ZERO_BUF_SIZE, tsegment, twrt);
size -= ZERO_BUF_SIZE;
}
break;
default:
panic();
break;
}
ofmt->legacy_output(data->segment, dptr, type, size, tsegment, twrt);
}