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cc65/libsrc/c64/acc_detect_chameleon.s
2018-04-26 09:18:54 -07:00

40 lines
846 B
ArmAsm
Executable File

;
; Marco van den Heuvel, 2018-04-25
;
; unsigned char detect_chameleon (void);
;
;/* Check for the presence of the Chameleon cartridge.
; *
; * Possible return values:
; * 0x00 : Chameleon cartridge not present
; * 0x01 : Chameleon cartridge present
; */
.export _detect_chameleon
.include "accelerator.inc"
_detect_chameleon:
lda #$00
tax
; Make sure the CPU is a 6510
.byte $1A ; NOP on 6510, INA on 65(S)C(E)02, 4510 and 65816
bne not_found
ldy CHAMELEON_CFGENA
lda #CHAMELEON_ENABLE_REGS
sta CHAMELEON_CFGENA
lda CHAMELEON_CFGENA
sty CHAMELEON_CFGENA
cmp #$FF
beq not_found
found:
lda #$01
.byte $24
not_found:
txa
rts