Apple-2-SW
/
apple2_fantavision_reloaded
mirror of https://github.com/Michaelangel007/apple2_fantavision_reloaded.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Add P5 Magic Number Disk Fields

This commit is contained in:
Michaelangel007 2017-03-26 12:40:56 -07:00
parent ef95103654
commit 66529a53c1
1 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
README.md
View File

@ -524,6 +524,16 @@ it comes from the P5 PROM ReadSector routine @ $C65C.
On my //e it looks this:
```asm
P5.Buff = $26 ; 16-bit pointer to dest
P5.SlotX16 = $2B ; i.e. $60 = Slot 6
; Magic Numbers "disk nisk nibbles"
ADDR_PROLOG_1 = $D5
ADDR_PROLOG_2 = $AA
ADDR_PROLOG_3 = $96
DATA_PROLOG_3 = $AD
ORG $C65C
P5.ReadSector
@ -532,23 +542,23 @@ On my //e it looks this:
C65E:BD 8C C0 ^2 LDA DRIVE_DATA,X
C661:10 FB BPL ^2 ;^ $C65E
C663:49 D5 ^3 EOR #$D5 ; Address 1st Prologue Field
C663:49 D5 ^3 EOR #ADDR_PROLOG_1
C665:D0 F7 BNE ^2 ;^ $C65E
C667:BD 8C C0 ^4 LDA DRIVE_DATA,X
C66A:10 FB BPL ^4 ;^ $C667
C66C:C9 AA CMP #$AA ; Address 2nd Prologue Field
C66C:C9 AA CMP #ADDR_PROLOG_2
C66E:D0 F3 BNE ^3 ;^ $C663
C670:EA NOP
C671:BD 8C C0 ^5 LDA DRIVE_DATA,X
C674:10 FB BPL ^5 ;^ $C671
C676:C9 96 CMP #$96 ; Address 3rd Prologue Field, NOTE: C=1 for $C68C !
C676:C9 96 CMP #ADDR_PROLOG_3 ; NOTE: C=1 for $C68C !
C678:F0 09 BEQ ^6 ;v $C683
C67A:28 PLP ;Looking for Address or Data prologue?
C67B:90 DF BCC ^0 ;^ $C65C
C67D:49 AD EOR #$AD ; Prologue Data Field: 3rd
C67D:49 AD EOR #DATA_PROLOG_3
C67F:F0 25 BEQ ^10 ;v $C6A6
C681:D0 D9 BNE ^0 ;^ $C65C
C683:A0 03 ^6 LDY #$03 ; Read 3 nibbles: Vol,Track,Sec, skip Checksum