;; Reference: http://www.cpcwiki.eu/forum/programming/crtc-type-detection-code/
TestCRTC:
; Detect CRTC type by Rhino ; Output
; a = CRTC type (0,1,2,3,4) getCRTCType
ld bc,#bc0c ; select reg 12 (R/W)
out (c),c
ld bc,#bd00+%0110100 ; write a value
out (c),c ; call wVb
ld b,#f5 ; wait Vbl
@vbLoop1
in a,(c)
rra
jr c,@vbLoop1
@vbLoop2
in a,(c)
rra
jr nc,@vbLoop2 ld b,#be ; read from status register
in a,(c)
ld d,a inc b ; read from #bf (read register)
in a,(c) cp d ; #be == #bf?
jr z,@CRTC_3_4 ; CRTC 0 1 or 2 cp c;%0110100 ; same value?
jr nz,@CRTC_1_2 ; CRTC 0 xor a
ret @CRTC_1_2
ld a,d
and a,%011111
jr nz,@CRTC_2 ; CRTC 1 ld a,1
ret ; CRTC 2 @CRTC_2
ld a,2
ret ; CRTC 3 or 4 @CRTC_3_4
ld bc,&f782
out (c),c
dec b
ld a,&F
out (c),a
inc b
out (c),c
dec b
in c,(c)
cp c
jr nz,@CRTC_4 ; CRTC 3 @CRTC_3
ld a,3
ret ; CRTC 4 @CRTC_4
ld a,4
ret | ★ AMSTRAD CPC ★ A voir aussi sur CPCrulez , les sujets suivants pourront vous intéresser... |
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