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Decoding RamFactor's memory detection
- Subject: Decoding RamFactor's memory detection
- From: BLuRry <brendan.robert@gmail.com>
- Date: Thu, 16 Aug 2012 06:32:58 -0700 (PDT)
- Complaints-to: groups-abuse@google.com
- Injection-info: glegroupsg2000goo.googlegroups.com; posting-host=70.123.154.97; posting-account=HyIOQgoAAAAfAUGOevdCSBhPYcDSPtM9
- Newsgroups: comp.sys.apple2
- Organization: http://groups.google.com
- User-agent: G2/1.0
Or rather I'm attempting to decode it anyway so I can get the bugs out of my RamFactor emulation code. I've traced the screen write portion of the diagnostic routine and found where it starts writing "256" to the screen. The question is, how is it getting the value for "2" to display?
A0 03 00 01F2 ..R...Z. cbcc : DEX
A0 02 00 01F2 ..R..... cbcd : BPL $cb9f
A0 02 00 01F2 ..R..... cb9f : LDA #$00
00 02 00 01F2 ..R...Z. cba1 : PHA
00 02 00 01F1 ..R...Z. cba2 : SEC
00 02 00 01F1 ..R...ZC cba3 : LDA $3e
00 02 00 01F1 ..R...ZC cba5 : SBC $cbde,X
70 02 00 01F1 ..R..... cba8 : PHA
70 02 00 01F0 ..R..... cba9 : LDA $3f
04 02 00 01F0 ..R..... cbab : SBC $cbe3,X
02 02 00 01F0 ..R....C cbae : BCC $cbba
02 02 00 01F0 ..R....C cbb0 : STA $3f
02 02 00 01F0 ..R....C cbb2 : PLA
70 02 00 01F1 ..R....C cbb3 : STA $3e
70 02 00 01F1 ..R....C cbb5 : PLA
00 02 00 01F2 ..R...ZC cbb6 : ADC #$00
01 02 00 01F2 ..R..... cbb8 : BNE $cba1
01 02 00 01F2 ..R..... cba1 : PHA
01 02 00 01F1 ..R..... cba2 : SEC
01 02 00 01F1 ..R....C cba3 : LDA $3e
70 02 00 01F1 ..R....C cba5 : SBC $cbde,X
E0 02 00 01F1 NVR..... cba8 : PHA
E0 02 00 01F0 NVR..... cba9 : LDA $3f
02 02 00 01F0 .VR..... cbab : SBC $cbe3,X
00 02 00 01F0 ..R...ZC cbae : BCC $cbba
00 02 00 01F0 ..R...ZC cbb0 : STA $3f
00 02 00 01F0 ..R...ZC cbb2 : PLA
E0 02 00 01F1 N.R....C cbb3 : STA $3e
E0 02 00 01F1 N.R....C cbb5 : PLA
01 02 00 01F2 ..R....C cbb6 : ADC #$00
02 02 00 01F2 ..R..... cbb8 : BNE $cba1
02 02 00 01F2 ..R..... cba1 : PHA
02 02 00 01F1 ..R..... cba2 : SEC
02 02 00 01F1 ..R....C cba3 : LDA $3e
E0 02 00 01F1 N.R....C cba5 : SBC $cbde,X
50 02 00 01F1 ..R....C cba8 : PHA
50 02 00 01F0 ..R....C cba9 : LDA $3f
00 02 00 01F0 ..R...ZC cbab : SBC $cbe3,X
FF 02 00 01F0 N.R..... cbae : BCC $cbba
FF 02 00 01F0 N.R..... cbba : PLA
50 02 00 01F1 ..R..... cbbb : PLA
02 02 00 01F2 ..R..... cbbc : BNE $cbc6
02 02 00 01F2 ..R..... cbc6 : INY
02 02 01 01F2 ..R..... cbc7 : EOR #$b0
B2 02 01 01F2 N.R..... cbc9 : JSR $fded
//------------------------------------------ WRITES 256k where A is '2'