base:c64gs_detection
C64 Game System (C64GS) detection
If you're developing a cartridge-based game and want to setup the controls differently on C64GS (since it doesn't have any physical keyboard), here is how to detect it.
check_c64gs ; returns 1 in x-register if true, otherwise 0. lda $01 ; save $01 temporarily pha lda #$36 ; kernal will now be visible at $e000 sta $01 ldx #$00 lda #$43 ; check bytes from kernal cmp $fc00 ; equals 'C' from 'COPYRIGHT 1990' in C64GS ROM bne cc_break cmp $fc0f ; equals 'C' from 'COMMODORE' bne cc_break cmp $fc1c ; equals first 'C' from 'ELECTRONICS' bne cc_break inx cc_break pla ; load old $01-value again sta $01 rts
How to use: Call the routine with 'jsr check_c64gs' and check the x-register afterwards.
base/c64gs_detection.txt · Last modified: 2015-04-17 04:30 by 127.0.0.1