Document Title: [mathdis.html (html file)]
/* * mathdis.c: Atari math box microcode disassembler for Red Baron, * Battlezone, and Tempest * * Copyright 1992, 1993, 1997 Eric Smith * * Permission is granted to reproduce and distribute copies of this program * for noncommercial use, provided the copyright notice is not altered. * This software is provided on an "AS-IS" basis, with no warranty. * * The input file should be a series of 256 lines each containing the * address and data (in hexadecimal, separated by whitespace) for one * microcode ROM word. For instance: "000 001700" * * To have any hope of understanding the disassembly, you'd better have the * math box schematics, a 2901 data sheet, and a lot of patience. * * $Header: /usr2/eric/vg/atari/mathbox/RCS/mathdis.c,v 1.5 1997/01/12 03:40:05 eric Exp eric $ */ #include#include #define I_MAX 256 unsigned long instruction [I_MAX]; int entry [I_MAX]; char *progname; void print_usage (FILE *f) { fprintf (f, "Usage: %s [objectfile [listingfile]]\n", progname); } void fatal (int retval, char *fmt, ...) { va_list ap; if (retval == 1) print_usage (stderr); else { fprintf (stderr, "%s: ", progname); va_start (ap, fmt); vfprintf (stderr, fmt, ap); va_end (ap); } exit (retval); } #define BUFSIZE 80 void read_inst (FILE *f) { int addr; int addr2; unsigned long val; char buffer [BUFSIZE]; for (addr = 0; addr < I_MAX; addr++) entry [addr] = -1; addr = 0; while (addr < I_MAX) { if (fgets (buffer, BUFSIZE, f) == NULL) fatal (2, "error reading object file\n"); if (strncmp (buffer, "Entry", 5) == 0) { sscanf (buffer + 6, "%x", & addr2); entry [addr] = addr2; continue; } if (strspn (buffer, "0123456789abcdef") != 3) continue; sscanf (buffer, "%x %x", & addr2, & val); if (addr2 != addr) fatal (3, "expected addr %02x, got %02x\n", addr, addr2); instruction [addr++] = val; } } void dis_fcn (FILE *file, int f, int s, int a, int b, int c) { static char *pc [2] = { "", " + 1" }; static char *mc [2] = { " - 1", "" }; switch ((f << 3) | s) { case 000: fprintf (file, "R%x + q%s", a, pc [c]); break; case 001: fprintf (file, "R%x + R%x%s", a, b, pc [c]); break; case 002: fprintf (file, "q%s", pc [c]); break; case 003: fprintf (file, "R%x%s", b, pc [c]); break; case 004: fprintf (file, "R%x%s", a, pc [c]); break; case 005: fprintf (file, "d + R%x%s", a, pc [c]); break; case 006: fprintf (file, "d + q%s", pc [c]); break; case 007: fprintf (file, "d%s", pc [c]); break; case 010: fprintf (file, "q - R%x%s", a, mc [c]); break; case 011: fprintf (file, "R%x - R%x%s", b, a, mc [c]); break; case 012: fprintf (file, "q%s", mc [c]); break; case 013: fprintf (file, "R%x%s", b, mc [c]); break; case 014: fprintf (file, "R%x%s", a, mc [c]); break; case 015: fprintf (file, "R%x - d%s", a, mc [c]); break; case 016: fprintf (file, "q - d%s", mc [c]); break; case 017: fprintf (file, "-d%s", mc [c]); break; case 020: fprintf (file, "R%x - q%s", a, mc [c]); break; case 021: fprintf (file, "R%x - R%x%s", a, b, mc [c]); break; case 022: fprintf (file, "-q%s", mc [c]); break; case 023: fprintf (file, "-R%x%s", b, mc [c]); break; case 024: fprintf (file, "-R%x%s", a, mc [c]); break; case 025: fprintf (file, "d - R%x%s", a, mc [c]); break; case 026: fprintf (file, "d - q%s", mc [c]); break; case 027: fprintf (file, "d%s", mc [c]); break; case 030: fprintf (file, "R%x | q", a); break; case 031: fprintf (file, "R%x | R%x", a, b); break; case 032: fprintf (file, "q"); break; case 033: fprintf (file, "R%x", b); break; case 034: fprintf (file, "R%x", a); break; case 035: fprintf (file, "d | R%x", a); break; case 036: fprintf (file, "d | q"); break; case 037: fprintf (file, "d"); break; case 040: fprintf (file, "R%x & q", a); break; case 041: fprintf (file, "R%x & R%x", a, b); break; case 042: fprintf (file, "0"); break; case 043: fprintf (file, "0"); break; case 044: fprintf (file, "0"); break; case 045: fprintf (file, "d & R%x", a); break; case 046: fprintf (file, "d & q"); break; case 047: fprintf (file, "0"); break; case 050: fprintf (file, "!R%x & q", a); break; case 051: fprintf (file, "!R%x & R%x", a, b); break; case 052: fprintf (file, "q"); break; case 053: fprintf (file, "R%x", b); break; case 054: fprintf (file, "R%x", a); break; case 055: fprintf (file, "!d & R%x", a); break; case 056: fprintf (file, "!d & q"); break; case 057: fprintf (file, "0"); break; case 060: fprintf (file, "R%x ^ q", a); break; case 061: fprintf (file, "R%x ^ R%x", a, b); break; case 062: fprintf (file, "q"); break; case 063: fprintf (file, "R%x", b); break; case 064: fprintf (file, "R%x", a); break; case 065: fprintf (file, "d ^ R%x", a); break; case 066: fprintf (file, "d ^ q"); break; case 067: fprintf (file, "d"); break; case 070: fprintf (file, "!R%x ^ q", a); break; case 071: fprintf (file, "!R%x ^ R%x", a, b); break; case 072: fprintf (file, "!q"); break; case 073: fprintf (file, "!R%x", b); break; case 074: fprintf (file, "!R%x", a); break; case 075: fprintf (file, "!d & R%x", a); break; case 076: fprintf (file, "!d & q"); break; case 077: fprintf (file, "!d"); break; } } void disassemble_inst (FILE *file, unsigned long inst, int *eos) { int f, sh, sl, d, a, b, c, m, l, s, h, j, jmp_addr, show_y; a = (inst >> 20) & 0x0f; b = (inst >> 16) & 0x0f; f = (inst >> 8) & 0x07; sh = (inst >> 12) & 0x0b; if (sh > 7) sh -= 4; sl = (inst >> 12) & 0x07; d = (inst >> 4) & 0x07; h = inst & 0x000800; l = inst & 0x000080; s = inst & 0x000008; j = inst & 0x000004; m = inst & 0x000002; c = inst & 0x000001; *eos = h || (j && !s); show_y = h || (j && s); fprintf (file, h ? "H" : " "); fprintf (file, s ? "S" : " "); fprintf (file, l ? "L" : " "); if (l) jmp_addr = inst >> 16; if (j) { if (s) fprintf (file, " (->%03x) ", jmp_addr); else fprintf (file, " ->%03x ", jmp_addr); } else fprintf (file, " "); if ((inst & 0xfffb) == 0x0090) fprintf (file, "--load addr--"); else { if (show_y) switch (d) { case 0: fprintf (file, "y = q = ("); break; case 1: fprintf (file, "y = ("); break; case 2: fprintf (file, "y = R%x, R%x = (", a, b); break; case 3: fprintf (file, "y = R%x = (", b); break; case 4: fprintf (file, "q = 1/2 * q, R%x = 1/2 * (y = ", b); break; case 5: fprintf (file, "R%x = 1/2 * (y = ", b); break; case 6: fprintf (file, "q = 2 * q, R%x = 2 * (y = ", b); break; case 7: fprintf (file, "R%x = 2 * (y = ", b); break; } else switch (d) { case 0: fprintf (file, "q = ("); break; case 1: fprintf (file, "y = ("); break; case 2: fprintf (file, "R%x = (", b); break; case 3: fprintf (file, "R%x = (", b); break; case 4: fprintf (file, "q = 1/2 * q, R%x = 1/2 * (", b); break; case 5: fprintf (file, "R%x = 1/2 * (", b); break; case 6: fprintf (file, "q = 2 * q, R%x = 2 * (", b); break; case 7: fprintf (file, "R%x = 2 * (", b); break; } dis_fcn (file, f, sh, a, b, c); if (sh != sl) { fprintf (file, ", "); dis_fcn (file, f, sl, a, b, c); } if (m) { fprintf (file, " ? "); dis_fcn (file, f, sh ^ 2, a, b, c); if (sh != sl) { fprintf (file, ", "); dis_fcn (file, f, sl ^ 2, a, b, c); } } fprintf (file, ") "); } } void disassemble_all (FILE *f) { int addr; int eos; fprintf (f, " jump\n" "entry addr hex hsl addr function\n" "----- ---- ------ --- ----- ---------------------------------\n"); for (addr = 0; addr < I_MAX; addr++) { if (entry [addr] >= 0) fprintf (f, "%03x-> ", entry [addr]); else fprintf (f, " "); fprintf (f, "%03x: %06x ", addr, instruction [addr]); disassemble_inst (f, instruction [addr], & eos); fprintf (f, "\n"); if (eos) fprintf (f, "\n"); } } int main (int argc, char *argv[]) { FILE *infile = stdin; FILE *outfile = stdout; char *fn; progname = argv [0]; switch (argc) { case 3: fn = argv [2]; if (strcmp (fn, "-")) { outfile = fopen (fn, "w"); if (! outfile) fatal (2, "error opening output file\n"); } case 2: fn = argv [1]; if (strcmp (fn, "-")) { infile = fopen (fn, "r"); if (! infile) fatal (2, "error opening input file\n"); } case 1: break; default: fatal (1, ""); } read_inst (infile); disassemble_all (outfile); return (0); }
