base:dtv_detect
DTV detect
Also detects C64 vs C128, and PAL vs NTSC.
;---------------------------------------------------------- ; DTV detect v1.0 by TLR (disassembly by groepaz) ; ; returns: ; ; a=$7f c64 ; $ff c128 ; $7d dtv1 (ntsc dtv) ; $75 dtv2 (early pal dtv) ; $74 dtv3 (recent pal dtv, hummer game) ; ; x=0 ntsc ; 1 pal ;---------------------------------------------------------- dtvdetect: PHP SEI LDA #$00 STA $FB STA $FC LDX #$FE CPX $D030 ROL $FB STA $D03F JSR ic03e LDA #$01 STA $D03F JSR ic03e LDA $FB CMP #$3A BNE skp1 JSR ic067 skp1: ROL $FB LDA #$00 STA $D03F ; test pal/ntsc JSR palntsc ROL $FC PLP LDA $FB LDX $FC RTS ;---------------------------------------------------------- !scr "TLR'06" ; signature, not used ;---------------------------------------------------------- ic03e: LDY #$D0 LDX #$40 JSR ic04e LDX #$80 JSR ic04e LDY #$D3 LDX #$00 ic04e: STY cmphi LDA #$55 lp1: STA $D000 cmphi=*+2 CMP $D300,X BNE skp2 EOR #$FF CMP #$55 BNE lp1 ic061: ROL $FB RTS skp2: CLC BCC ic061 ;---------------------------------------------------------- ic067: LDX #$1F STX $FF lp2: LDA ic086,X STA $D320,X DEX BPL lp2 LDA #$0F STA $D33A lp3: LDA $D33F LSR A BCS lp3 LDA $FF BEQ skp3 RTS skp3: SEC RTS ic086: !byte $89,$c0,0,0, 0,0,0,0 !byte 0,0,0,0, 0,0,0,0 !byte $ff,0,0,0, 0,0,0,0 !byte 1,0,0,5, 0,0,0,0 ;---------------------------------------------------------- palntsc: lp4: LDA $D011 BMI lp4 lp5: LDA $D011 BPL lp5 lp6: LDA $D012 CMP #$20 BEQ skp4 LDA $D011 BMI lp6 CLC ; C=0 - ntsc skp4: RTS ;----------------------------------------------------------
base/dtv_detect.txt · Last modified: 2015-04-17 04:31 by 127.0.0.1