(copy_text_and_data): Add RISCiX changes.

src/unexec.c

@@ -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;