diff options
Diffstat (limited to 'src/devices/cpu/m6502/xavix2000.cpp')
-rw-r--r-- | src/devices/cpu/m6502/xavix2000.cpp | 128 |
1 files changed, 64 insertions, 64 deletions
diff --git a/src/devices/cpu/m6502/xavix2000.cpp b/src/devices/cpu/m6502/xavix2000.cpp index ab40752b1fe..afbf87fd8c6 100644 --- a/src/devices/cpu/m6502/xavix2000.cpp +++ b/src/devices/cpu/m6502/xavix2000.cpp @@ -4,12 +4,12 @@ xavix2000.cpp - The dies for these are marked - - SSD 2000 NEC 85605-621 - and possibly - SSD 2002 NEC 85054-611 (although this might use even more opcodes and need it's own file) - + The dies for these are marked + + SSD 2000 NEC 85605-621 + and possibly + SSD 2002 NEC 85054-611 (although this might use even more opcodes and need it's own file) + 6502 with custom opcodes integrated gfx / sound @@ -17,64 +17,64 @@ see xavix.cpp for basic notes - the machines using the '2000' series chips seem to have more extra - opcodes, so presumably these were only available in those models. - of note, push x / push y and pull x / pull y - - Dirt Rebel MX, which is confirmed as 2000 type however seems to require - some of the documented but 'undocumented' opcodes on the 6502 to have additonal - meaning for one specific function on startup - - 01BC37: A0 3F ldy #$3f - 01BC39: B2 ?? - 01BC3A: 1B ?? - 9B ?? - -- outer loop - 01BC3C: 98 tya - 01BC3D: 5B (has to be 1 byte?) - -- inner loop - 01BC3E: A3 (has to be 1 byte) - 73 (could be 3 byte?) - 01BC40: 83 FB presumably fb is the address - 01BC42: A7 (presumably 1 byte) - 73 (could be 3 byte?) - 01BC44: 87 FB presumably fb is the address - 01BC46: D0 F6 bne $1bc3e - 01BC48: 88 dey - 01BC49: 10 F1 bpl $1bc3c - 01BC4B: 8D FB 00 sta $00fb - 01BC4E: A3 ?? - 01BC4F: 8D FA 00 sta $00fa - 01BC52: 07 ?? - -- - 01BC53: D0 03 bne $1bc58 - 01BC55: CE fa 00 dec $00fa - 01BC58: 80 retf - - this is presumably meant to be similar to the function found in Namco - Nostalgia 2 - - 09FFD8: A9 3F lda #$3f - 09FFDA: 85 01 sta $01 - 09FFDC: A0 00 ldy #$00 - 09FFDE: AD FA 00 lda $00fa - 09FFE1: 71 00 adc ($00), y - 09FFE3: 8D FA 00 sta $00fa - 09FFE6: C8 iny - 09FFE7: AD FB 00 lda $00fb - 09FFEA: 71 00 adc ($00), y - 09FFEC: 8D FB 00 sta $00fb - 09FFEF: C8 iny - 09FFF0: D0 EC bne $c - 09FFF2: C6 01 dec $01 - 09FFF4: 10 E8 bpl $9ffde - 09FFF6: 0D FA 00 ora $00fa - -- - 09FFF9: D0 03 bne $9fffe - 09FFFB: CE FA 00 dec $00fa - 09FFFE: 80 retf - - + the machines using the '2000' series chips seem to have more extra + opcodes, so presumably these were only available in those models. + of note, push x / push y and pull x / pull y + + Dirt Rebel MX, which is confirmed as 2000 type however seems to require + some of the documented but 'undocumented' opcodes on the 6502 to have additonal + meaning for one specific function on startup + + 01BC37: A0 3F ldy #$3f + 01BC39: B2 ?? + 01BC3A: 1B ?? + 9B ?? + -- outer loop + 01BC3C: 98 tya + 01BC3D: 5B (has to be 1 byte?) + -- inner loop + 01BC3E: A3 (has to be 1 byte) + 73 (could be 3 byte?) + 01BC40: 83 FB presumably fb is the address + 01BC42: A7 (presumably 1 byte) + 73 (could be 3 byte?) + 01BC44: 87 FB presumably fb is the address + 01BC46: D0 F6 bne $1bc3e + 01BC48: 88 dey + 01BC49: 10 F1 bpl $1bc3c + 01BC4B: 8D FB 00 sta $00fb + 01BC4E: A3 ?? + 01BC4F: 8D FA 00 sta $00fa + 01BC52: 07 ?? + -- + 01BC53: D0 03 bne $1bc58 + 01BC55: CE fa 00 dec $00fa + 01BC58: 80 retf + + this is presumably meant to be similar to the function found in Namco + Nostalgia 2 + + 09FFD8: A9 3F lda #$3f + 09FFDA: 85 01 sta $01 + 09FFDC: A0 00 ldy #$00 + 09FFDE: AD FA 00 lda $00fa + 09FFE1: 71 00 adc ($00), y + 09FFE3: 8D FA 00 sta $00fa + 09FFE6: C8 iny + 09FFE7: AD FB 00 lda $00fb + 09FFEA: 71 00 adc ($00), y + 09FFEC: 8D FB 00 sta $00fb + 09FFEF: C8 iny + 09FFF0: D0 EC bne $c + 09FFF2: C6 01 dec $01 + 09FFF4: 10 E8 bpl $9ffde + 09FFF6: 0D FA 00 ora $00fa + -- + 09FFF9: D0 03 bne $9fffe + 09FFFB: CE FA 00 dec $00fa + 09FFFE: 80 retf + + ***************************************************************************/ #include "emu.h" |