Commit 52a2b13b authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(copy_text_and_data): Add RISCiX changes.

parent c9a95ab2
......@@ -909,9 +909,95 @@ copy_text_and_data (new, a_out)
lseek (new, (long) N_TXTOFF (hdr), 0);
#endif /* no A_TEXT_SEEK */
#ifdef RISCiX
/* Acorn's RISC-iX has a wacky way of initialising the position of the heap.
* There is a little table in crt0.o that is filled at link time with
* the min and current brk positions, among other things. When start()
* runs, it copies the table to where these parameters live during
* execution. This data is in text space, so it cannot be modified here
* before saving the executable, so the data is written manually. In
* addition, the table does not have a label, and the nearest accessable
* label (mcount) is not prefixed with a '_', thus making it inaccessable
* from within C programs. To overcome this, emacs's executable is passed
* through the command 'nm %s | fgrep mcount' into a pipe, and the
* resultant output is then used to find the address of 'mcount'. As far as
* is possible to determine, in RISC-iX releases prior to 1.2, the negative
* offset of the table from mcount is 0x2c, whereas from 1.2 onwards it is
* 0x30. bss_end has been rounded up to page boundary. This solution is
* based on suggestions made by Kevin Welton and Steve Hunt of Acorn, and
* avoids the need for a custom version of crt0.o for emacs which has its
* table in data space.
*/
{
char command[1024];
char errbuf[1024];
char address_text[32];
int proforma[4];
FILE *pfile;
char *temp_ptr;
char c;
int mcount_address, mcount_offset, count;
extern char *_execname;
/* The use of _execname is incompatible with RISCiX 1.1 */
sprintf (command, "nm %s | fgrep mcount", _execname);
if ( (pfile = popen(command, "r")) == NULL)
{
sprintf (errbuf, "Could not open pipe");
PERROR (errbuf);
}
count=0;
while ( ((c=getc(pfile)) != EOF) && (c != ' ') && (count < 31))
address_text[count++]=c;
address_text[count]=0;
if ((count == 0) || pclose(pfile) != NULL)
{
sprintf (errbuf, "Failed to execute the command '%s'\n", command);
PERROR (errbuf);
}
sscanf(address_text, "%x", &mcount_address);
ptr = (char *) unexec_text_start;
mcount_offset = (char *)mcount_address - ptr;
#ifdef RISCiX_1_1
#define EDATA_OFFSET 0x2c
#else
#define EDATA_OFFSET 0x30
#endif
end = ptr + mcount_offset - EDATA_OFFSET;
printf ("Writing from %08x to %08x\n", ptr, end);
write_segment (new, ptr, end);
proforma[0] = bss_end; /* becomes _edata */
proforma[1] = bss_end; /* becomes _end */
proforma[2] = bss_end; /* becomes _minbrk */
proforma[3] = bss_end; /* becomes _curbrk */
puts ("Writing 'args_proforma' (16 bytes)");
write (new, proforma, 16);
temp_ptr = ptr;
ptr = end + 16;
end = temp_ptr + hdr.a_text;
printf ("Writing from %08x to %08x\n", ptr, end);
write_segment (new, ptr, end);
}
#else /* !RISCiX */
ptr = (char *) unexec_text_start;
end = ptr + hdr.a_text;
write_segment (new, ptr, end);
#endif /* RISCiX */
ptr = (char *) unexec_data_start;
end = ptr + hdr.a_data;
......
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