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nasm/outrdf2.c
H. Peter Anvin eba20a73f2 NASM 0.98p3
2002-04-30 20:53:55 +00:00

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/* outrdf2.c output routines for the Netwide Assembler to produce
* RDOFF version 2 format object files (which are intended
* mainly for use in proprietary projects, as the code to
* load and execute them is very simple). They will also be
* used for device drivers and possibly some executable files
* in the MOSCOW operating system. See Rdoff.txt for
* details.
*
* The Netwide Assembler is copyright (C) 1996-1998 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "nasm.h"
#include "nasmlib.h"
#include "outform.h"
/* VERBOSE_WARNINGS: define this to add some extra warnings... */
#define VERBOSE_WARNINGS
#ifdef OF_RDF2
#define RDF_MAXSEGS 64 /* maximum number of segments - user configurable */
typedef unsigned short int16;
typedef unsigned char byte;
static const char *RDOFF2Id = "RDOFF2"; /* written to start of RDOFF files */
/* the records that can be found in the RDOFF header */
/* Note that whenever a segment is referred to in the RDOFF file, its number
* is always half of the segment number that NASM uses to refer to it; this
* is because NASM only allocates even numbered segments, so as to not
* waste any of the 16 bits of segment number written to the file - this
* allows up to 65533 external labels to be defined; otherwise it would be
* 32764. */
struct RelocRec {
byte type; /* must be 1, or 6 for segment base ref */
byte reclen; /* set to 8 */
byte segment; /* only 0 for code, or 1 for data supported,
* but add 64 for relative refs (ie do not require
* reloc @ loadtime, only linkage) */
long offset; /* from start of segment in which reference is loc'd */
byte length; /* 1 2 or 4 bytes */
int16 refseg; /* segment to which reference refers to */
};
struct ImportRec {
byte type; /* must be 2, or 7 for FAR import */
byte reclen; /* equals 3+label length */
int16 segment; /* segment number allocated to the label for reloc
* records - label is assumed to be at offset zero
* in this segment, so linker must fix up with offset
* of segment and of offset within segment */
char label[33]; /* zero terminated... should be written to file until
* the zero, but not after it - max len = 32 chars */
};
struct ExportRec {
byte type; /* must be 3 */
byte reclen; /* equals 6+label length */
byte segment; /* segment referred to (0/1) */
long offset; /* offset within segment */
char label[33]; /* zero terminated as above. max len = 32 chars */
};
struct DLLRec {
byte type; /* must be 4 */
byte reclen; /* equals 1+library name */
char libname[128]; /* name of library to link with at load time */
};
struct BSSRec {
byte type; /* must be 5 */
byte reclen; /* equeals 4 */
long amount; /* number of bytes BSS to reserve */
};
#define COUNT_SEGTYPES 9
static char * segmenttypes[COUNT_SEGTYPES] = {
"null", "text", "code", "data", "comment", "lcomment", "pcomment",
"symdebug", "linedebug"
};
static int segmenttypenumbers[COUNT_SEGTYPES] = {
0, 1, 1, 2, 3, 4, 5, 6, 7
};
/* code for managing buffers needed to seperate code and data into individual
* sections until they are ready to be written to the file.
* We'd better hope that it all fits in memory else we're buggered... */
#define BUF_BLOCK_LEN 4088 /* selected to match page size (4096)
* on 80x86 machines for efficiency */
/***********************************************************************
* Actual code to deal with RDOFF2 ouput format begins here...
*/
/* global variables set during the initialisation phase */
static struct SAA *seg[RDF_MAXSEGS]; /* seg 0 = code, seg 1 = data */
static struct SAA *header; /* relocation/import/export records */
static FILE *ofile;
static efunc error;
static struct seginfo {
char *segname;
int segnumber;
int16 segtype;
int16 segreserved;
long seglength;
} segments[RDF_MAXSEGS];
static int nsegments;
static long bsslength;
static long headerlength;
static void rdf2_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
{
int segtext, segdata, segbss;
/* set up the initial segments */
segments[0].segname = ".text";
segments[0].segnumber = 0;
segments[0].segtype = 1;
segments[0].segreserved = 0;
segments[0].seglength = 0;
segments[1].segname = ".data";
segments[1].segnumber = 1;
segments[1].segtype = 2;
segments[1].segreserved = 0;
segments[1].seglength = 0;
segments[2].segname = ".bss";
segments[2].segnumber = 2;
segments[2].segtype = 0xFFFF; /* reserved - should never be produced */
segments[2].segreserved = 0;
segments[2].seglength = 0;
nsegments = 3;
ofile = fp;
error = errfunc;
seg[0] = saa_init(1L);
seg[1] = saa_init(1L);
seg[2] = NULL; /* special case! */
header = saa_init(1L);
segtext = seg_alloc();
segdata = seg_alloc();
segbss = seg_alloc();
if (segtext != 0 || segdata != 2 || segbss != 4)
error(ERR_PANIC,"rdf segment numbers not allocated as expected (%d,%d,%d)",
segtext,segdata,segbss);
bsslength=0;
headerlength = 0;
}
static long rdf2_section_names(char *name, int pass, int *bits)
{
int i;
char * p, * q;
int code = -1;
int reserved = 0;
/*
* Default is 32 bits, in the text segment.
*/
if (!name) {
*bits = 32;
return 0;
}
/* look for segment type code following segment name */
p = name;
while (*p && !isspace(*p)) p++;
if (*p) { /* we're now in whitespace */
*p++ = '\0';
while (*p && isspace(80)) *p++ = '\0';
}
if (*p) { /* we're now in an attribute value */
/*
* see if we have an optional ',number' following the type code
*/
if ((q = strchr(p, ','))) {
*q++ = '\0';
reserved = readnum(q, &i);
if (i) {
error(ERR_NONFATAL, "value following comma must be numeric");
reserved = 0;
}
}
/*
* check it against the text strings in segmenttypes
*/
for (i = 0; i < COUNT_SEGTYPES; i++)
if (!nasm_stricmp(p, segmenttypes[i])) {
code = segmenttypenumbers[i];
break;
}
if (code == -1) { /* didn't find anything */
code = readnum(p, &i);
if (i) {
error(ERR_NONFATAL, "unrecognised RDF segment type (%s)",p);
code = 3;
}
}
}
for (i = 0; i < nsegments; i++) {
if (!strcmp(name, segments[i].segname)) {
if (code != -1 || reserved != 0)
error(ERR_NONFATAL, "segment attributes specified on"
" redeclaration of segment");
return segments[i].segnumber * 2;
}
}
/* declaring a new segment! */
if (code == -1) {
error(ERR_NONFATAL, "new segment declared without type code");
code = 3;
}
if (nsegments == RDF_MAXSEGS) {
error(ERR_FATAL, "reached compiled-in maximum segment limit (%d)",
RDF_MAXSEGS);
return NO_SEG;
}
segments[nsegments].segname = nasm_strdup(name);
i = seg_alloc();
if (i % 2 != 0)
error(ERR_PANIC, "seg_alloc() returned odd number");
segments[nsegments].segnumber = i >> 1;
segments[nsegments].segtype = code;
segments[nsegments].segreserved = reserved;
segments[nsegments].seglength = 0;
seg[nsegments] = saa_init(1L);
return i;
}
static void write_reloc_rec(struct RelocRec *r)
{
char buf[4],*b;
if (r->refseg != (int16)NO_SEG && (r->refseg & 1)) /* segment base ref */
r->type = 6;
r->refseg >>= 1; /* adjust segment nos to RDF rather than NASM */
saa_wbytes(header,&r->type,1);
saa_wbytes(header,&r->reclen,1);
saa_wbytes(header,&r->segment,1);
b = buf; WRITELONG(b,r->offset);
saa_wbytes(header,buf,4);
saa_wbytes(header,&r->length,1);
b = buf; WRITESHORT(b,r->refseg);
saa_wbytes(header,buf,2);
headerlength += r->reclen + 2;
}
static void write_export_rec(struct ExportRec *r)
{
char buf[4], *b;
r->segment >>= 1;
saa_wbytes(header,&r->type,1);
saa_wbytes(header,&r->reclen,1);
saa_wbytes(header,&r->segment,1);
b = buf; WRITELONG(b,r->offset);
saa_wbytes(header,buf,4);
saa_wbytes(header,r->label,strlen(r->label) + 1);
headerlength += r->reclen + 2;
}
static void write_import_rec(struct ImportRec *r)
{
char buf[4], *b;
r->segment >>= 1;
saa_wbytes(header,&r->type,1);
saa_wbytes(header,&r->reclen,1);
b = buf; WRITESHORT(b,r->segment);
saa_wbytes(header,buf,2);
saa_wbytes(header,r->label,strlen(r->label) + 1);
headerlength += r->reclen + 2;
}
static void write_bss_rec(struct BSSRec *r)
{
char buf[4], *b;
saa_wbytes(header,&r->type,1);
saa_wbytes(header,&r->reclen,1);
b = buf; WRITELONG(b,r->amount);
saa_wbytes(header,buf,4);
headerlength += r->reclen + 2;
}
static void write_dll_rec(struct DLLRec *r)
{
saa_wbytes(header,&r->type,1);
saa_wbytes(header,&r->reclen,1);
saa_wbytes(header,r->libname,strlen(r->libname) + 1);
headerlength += r->reclen + 2;
}
static void rdf2_deflabel(char *name, long segment, long offset,
int is_global, char *special)
{
struct ExportRec r;
struct ImportRec ri;
#ifdef VERBOSE_WARNINGS
static int warned_common = 0;
#endif
static int farsym = 0;
static int i;
if (special) {
while(*special == ' ' || *special == '\t') special++;
if (!nasm_stricmp(special, "far")) {
farsym = 1;
}
else if (!nasm_stricmp(special, "near")) {
farsym = 0;
}
else
error(ERR_NONFATAL, "unrecognised symbol type `%s'", special);
}
if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
error (ERR_NONFATAL, "unrecognised special symbol `%s'", name);
return;
}
if (is_global == 2) {
#ifdef VERBOSE_WARNINGS
if (!warned_common) {
error(ERR_WARNING,"common declarations not supported: using extern");
warned_common = 1;
}
#endif
is_global = 1;
}
for (i = 0; i < nsegments; i++) {
if (segments[i].segnumber == segment>>1) break;
}
if (i >= nsegments) { /* EXTERN declaration */
if (farsym)
ri.type = 7;
else
ri.type = 2;
ri.segment = segment;
strncpy(ri.label,name,32);
ri.label[32] = 0;
ri.reclen = 3 + strlen(ri.label);
write_import_rec(&ri);
} else if (is_global) {
r.type = 3;
r.segment = segment;
r.offset = offset;
strncpy(r.label,name,32);
r.label[32] = 0;
r.reclen = 6 + strlen(r.label);
write_export_rec(&r);
}
}
static void membufwrite(int segment, void * data, int bytes)
{
int i;
char buf[4], * b;
for (i = 0; i < nsegments; i++) {
if (segments[i].segnumber == segment) break;
}
if (i == nsegments)
error(ERR_PANIC, "can't find segment %d", segment);
if (bytes < 0) {
b = buf;
if (bytes == -2)
WRITESHORT(b,*(short *)data);
else
WRITELONG(b,*(long *)data);
data = buf;
bytes = -bytes;
}
segments[i].seglength += bytes;
saa_wbytes(seg[i],data,bytes);
}
static int getsegmentlength(int segment)
{
int i;
for (i = 0; i < nsegments; i++) {
if (segments[i].segnumber == segment) break;
}
if (i == nsegments)
error(ERR_PANIC, "can't find segment %d", segment);
return segments[i].seglength;
}
static void rdf2_out (long segto, void *data, unsigned long type,
long segment, long wrt)
{
long bytes = type & OUT_SIZMASK;
struct RelocRec rr;
unsigned char databuf[4],*pd;
int seg;
if (segto == NO_SEG) {
if ((type & OUT_TYPMASK) != OUT_RESERVE)
error (ERR_NONFATAL, "attempt to assemble code in ABSOLUTE space");
return;
}
segto >>= 1; /* convert NASM segment no to RDF number */
for (seg = 0; seg < nsegments; seg++) {
if (segments[seg].segnumber == segto) break;
}
if (seg >= nsegments) {
error(ERR_NONFATAL,"specified segment not supported by rdf output format");
return;
}
if (wrt != NO_SEG) {
wrt = NO_SEG; /* continue to do _something_ */
error (ERR_NONFATAL, "WRT not supported by rdf output format");
}
type &= OUT_TYPMASK;
if (segto == 2 && type != OUT_RESERVE)
{
error(ERR_NONFATAL, "BSS segments may not be initialised");
/* just reserve the space for now... */
if (type == OUT_REL2ADR)
bytes = 2;
else
bytes = 4;
type = OUT_RESERVE;
}
if (type == OUT_RESERVE) {
if (segto == 2) /* BSS segment space reserverd */
bsslength += bytes;
else
while (bytes --)
membufwrite(segto,databuf,1);
}
else if (type == OUT_RAWDATA) {
if (segment != NO_SEG)
error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
membufwrite(segto,data,bytes);
}
else if (type == OUT_ADDRESS) {
/* if segment == NO_SEG then we are writing an address of an
object within the same segment - do not produce reloc rec. */
/* FIXME - is this behaviour sane? at first glance it doesn't
appear to be. Must test this thoroughly...! */
if (segment != NO_SEG)
{
/* it's an address, so we must write a relocation record */
rr.type = 1; /* type signature */
rr.reclen = 8;
rr.segment = segto; /* segment we're currently in */
rr.offset = getsegmentlength(segto); /* current offset */
rr.length = bytes; /* length of reference */
rr.refseg = segment; /* segment referred to */
write_reloc_rec(&rr);
}
pd = databuf; /* convert address to little-endian */
if (bytes == 2)
WRITESHORT (pd, *(long *)data);
else
WRITELONG (pd, *(long *)data);
membufwrite(segto,databuf,bytes);
}
else if (type == OUT_REL2ADR)
{
if (segment == segto)
error(ERR_PANIC, "intra-segment OUT_REL2ADR");
rr.reclen = 8;
rr.offset = getsegmentlength(segto); /* current offset */
rr.length = 2; /* length of reference */
rr.refseg = segment; /* segment referred to (will be >>1'd)*/
if (segment != NO_SEG && segment % 2) {
rr.type = 6;
rr.segment = segto; /* memory base refs *aren't ever* relative! */
write_reloc_rec(&rr);
/* what do we put in the code? Simply the data. This should almost
* always be zero, unless someone's doing segment arithmetic...
*/
rr.offset = *(long *) data;
}
else
{
rr.type = 1; /* type signature */
rr.segment = segto+64; /* segment we're currently in + rel flag */
write_reloc_rec(&rr);
/* work out what to put in the code: offset of the end of this operand,
* subtracted from any data specified, so that loader can just add
* address of imported symbol onto it to get address relative to end of
* instruction: import_address + data(offset) - end_of_instrn */
rr.offset = *(long *)data -(rr.offset + bytes);
}
membufwrite(segto,&rr.offset,-2);
}
else if (type == OUT_REL4ADR)
{
if (segment == segto)
error(ERR_PANIC, "intra-segment OUT_REL4ADR");
if (segment != NO_SEG && segment % 2) {
error(ERR_PANIC, "erm... 4 byte segment base ref?");
}
rr.type = 1; /* type signature */
rr.segment = segto+64; /* segment we're currently in + rel tag */
rr.offset = getsegmentlength(segto); /* current offset */
rr.length = 4; /* length of reference */
rr.refseg = segment; /* segment referred to */
rr.reclen = 8;
write_reloc_rec(&rr);
rr.offset = *(long *)data -(rr.offset + bytes);
membufwrite(segto,&rr.offset,-4);
}
}
static void rdf2_cleanup (int debuginfo) {
long l;
struct BSSRec bs;
int i;
(void) debuginfo;
/* should write imported & exported symbol declarations to header here */
/* generate the output file... */
fwrite(RDOFF2Id,6,1,ofile); /* file type magic number */
if (bsslength != 0) /* reserve BSS */
{
bs.type = 5;
bs.amount = bsslength;
bs.reclen = 4;
write_bss_rec(&bs);
}
/*
* calculate overall length of the output object
*/
l = headerlength + 4;
for (i = 0; i < nsegments; i++) {
if (i == 2) continue; /* skip BSS segment */
l += 10 + segments[i].seglength;
}
l += 10; /* null segment */
fwritelong(l, ofile);
fwritelong(headerlength, ofile);
saa_fpwrite(header,ofile); /* dump header */
saa_free(header);
for (i = 0; i < nsegments; i++) {
if (i == 2) continue;
fwriteshort(segments[i].segtype, ofile);
fwriteshort(segments[i].segnumber, ofile);
fwriteshort(segments[i].segreserved, ofile);
fwritelong(segments[i].seglength, ofile);
saa_fpwrite(seg[i], ofile);
saa_free(seg[i]);
}
/* null segment - write 10 bytes of zero */
fwritelong(0,ofile);
fwritelong(0,ofile);
fwriteshort(0,ofile);
fclose(ofile);
}
static long rdf2_segbase (long segment) {
return segment;
}
static int rdf2_directive (char *directive, char *value, int pass) {
struct DLLRec r;
if (! strcmp(directive, "library")) {
if (pass == 1) {
r.type = 4;
strcpy(r.libname, value);
write_dll_rec(&r);
}
return 1;
}
return 0;
}
static void rdf2_filename (char *inname, char *outname, efunc error) {
standard_extension(inname,outname,".rdf",error);
}
static char *rdf2_stdmac[] = {
"%define __SECT__ [section .text]",
"%imacro library 1+.nolist",
"[library %1]",
"%endmacro",
"%macro __NASM_CDecl__ 1",
"%endmacro",
NULL
};
static int rdf2_set_info(enum geninfo type, char **val)
{
return 0;
}
struct ofmt of_rdf2 = {
"Relocatable Dynamic Object File Format v2.0",
"rdf",
NULL,
null_debug_arr,
&null_debug_form,
rdf2_stdmac,
rdf2_init,
rdf2_set_info,
rdf2_out,
rdf2_deflabel,
rdf2_section_names,
rdf2_segbase,
rdf2_directive,
rdf2_filename,
rdf2_cleanup
};
#endif /* OF_RDF2 */
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