$D46 and $D47 should be changed from 0xCD 0x15 to 0x60 0x5B. The new code should be put at location $5B60 (lives on the second EPROM) in memory which is filled with 0xFF's on the stock ROMs.
; modify Galaxy Ranger to display LD-V1000 status code during "WARM-UP"
org 0x5b60
start:
; preserve registers
push hl
push bc
push af
; set target pointer
ld hl, 0xF169 ; right above $F189 'warming up' text (each row is 0x20$
ld a, (0xc800) ; LD-V1000 I/O flip-flop
ld b, a
; isolate top nibble
srl a ; A >>= 4
srl a
srl a
srl a
cp 0xA ; Acculumulator - 0xA is what?
jr c, Its0to9 ; if carry is set, it means subtraction resulte$
; A-F (hex)
add 0x37 ; make it ASCII
jr StoreIt
Its0to9:
add 0x30 ; make it ASCII
StoreIt:
ld (hl), a
inc hl
; now grab lower nibble
ld a, 0xF
and b
cp 0xA
jr c, Its0to9_2
add 0x37
jr StoreIt2
Its0to9_2:
add 0x30
StoreIt2:
ld (hl), a
; restore registers
pop af
pop bc
pop hl
; go to where we were supposed to originally
jp 0x15CD
Nice work :)
ReplyDeleteNice work :)
ReplyDelete