mirror of
https://github.com/cc65/cc65.git
synced 2024-11-18 00:07:21 +00:00
56 lines
1.4 KiB
ArmAsm
Executable File
56 lines
1.4 KiB
ArmAsm
Executable File
;
|
|
; Marco van den Heuvel, 2018-04-27
|
|
;
|
|
|
|
; unsigned char detect_c65 (void);
|
|
;
|
|
;/* Check for the presence of a C65/C64DX in C64 mode.
|
|
; *
|
|
; * Possible return values:
|
|
; * 0x00 : C65/C64DX in C64 mode not present
|
|
; * 0x01 : C65/C64DX in C64 mode present
|
|
; */
|
|
|
|
.export _detect_c65
|
|
|
|
.include "accelerator.inc"
|
|
|
|
_detect_c65:
|
|
ldy $D000
|
|
|
|
; Make sure the CPU is not a 65816
|
|
clc
|
|
.byte $E2,$01 ; NOP #$01 on 6510 and 65(S)C02, LDA $(01,S),Y on 65CE02 and 4510, SEP #$01 on 65816
|
|
lda #$00
|
|
tax
|
|
bcs not_found ; carry will be set on 65816
|
|
|
|
; Make sure the CPU is not a 6510
|
|
.byte $1A ; NOP on 6510, INA on 65(S)C(E)02
|
|
beq not_found
|
|
txa
|
|
|
|
; Make sure the CPU is a 65CE02/4510
|
|
.byte $A3,$A3 ; NOP NOP on 65(S)C02, LDZ #$A3 on 65CE02 and 4510
|
|
.byte $6B ; NOP on 65(S)C02, TZA on 65CE02 and 4510
|
|
cmp #$A3
|
|
bne not_found
|
|
|
|
; Switch to VICIII mode and check if $D040 is a mirror of $D000
|
|
ldy #C65_VICIII_UNLOCK_1
|
|
sty C65_VICIII_KEY
|
|
ldy #C65_VICIII_UNLOCK_2
|
|
sty C65_VICIII_KEY
|
|
cpy $D040
|
|
bne found
|
|
inc $D000
|
|
cpy $D040
|
|
bne not_found
|
|
|
|
found:
|
|
lda #$01
|
|
not_found:
|
|
sty $D000
|
|
sta C65_VICIII_KEY
|
|
rts
|