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Lucky Ball 96: Added technical notes about

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how the code resets itself.
This commit is contained in:
RobertoFresca 2018-01-08 15:40:04 -03:00
parent 191860a754
commit 5f57ed53de
1 changed files with 31 additions and 0 deletions
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31
src/mame/drivers/luckybal.cpp
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@ -212,6 +212,37 @@
'-------------'
*********************************************************************
Dev notes:
Currently the program is resetting due to a couple of routines that
compare writes/reads and jump to offset 0000.
002E5: F3 di
002E6: ED 5E im 2
002E8: 31 F5 FE ld sp,$FEF5
002EB: CD C0 02 call $02C0
002EE: 3E 44 ld a,$44
002F0: D3 C3 out ($C3),a
002F2: D3 C3 out ($C3),a
002F4: 3E 5A ld a,$5A ; loads $5A (bitpattern)
002F6: D3 C0 out ($C0),a ; out to DAC (through PPI, port A)
002F8: DB C0 in a,($C0) ; loads from DAC???
002FA: FE 5A cp $5A ; compare for the same value like it was RAM
002FC: 28 04 jr z,$00302 ; match?... jumps over the reset.
002FE: FB ei ; otherwise...
002FF: C3 00 00 jp $0000 : RESET.
00302: 3E A5 ld a,$A5 ; loads $A5 (inverted bitpattern)
00304: D3 C0 out ($C0),a ; out to DAC (through PPI, port A)
00306: DB C0 in a,($C0) ; loads from DAC???
00308: FE A5 cp $A5 ; compare for the same value like it was RAM
0030A: 28 04 jr z,$00310 ; match?... jumps over the reset.
0030C: FB ei ; otherwise...
0030D: C3 00 00 jp $0000 : RESET.
00310: AF xor a
00311: D3 C0 out ($C0),a
*********************************************************************/