first changes for atari5200 target

2014-03-01 17:20:09 +01:00
parent 9c95306a69
commit c8f7f2f161
19 changed files with 608 additions and 218 deletions
--- a/libsrc/atari5200/y2k.inc
+++ b/libsrc/atari5200/y2k.inc
@@ -0,0 +1,41 @@
+;-----------------------------------------------------------
+; Y2K FIX by Alan Davis, Dennis Debro, and Ronen Habot
+;-----------------------------------------------------------
+Y2K     LDY     #$00            ; Copy BIOS opening screen to RAM
+        LDA     #$FD
+        STA     TEMPH
+        LDA     #$58            ; Assume 2 port system
+        LDX     $FD32
+        CPX     #$E8            ; Is this a 4 port?
+        BNE     Y2K0            ; Jump if not
+        LDA     #$42            ; Yes, 4 port system
+Y2K0    STA     TEMPL           
+Y2K1    LDA     (TEMPL),Y       
+        STA     $0600,Y
+        INY     
+        BNE     Y2K1
+        LDY     #$50
+        INC     TEMPH
+Y2K2    LDA     (TEMPL),Y       
+        STA     $0700,Y
+        DEY     
+        BPL     Y2K2
+        LDA     #$D4            ; Point to copyright string
+        STA     $0724
+        LDA     #$BF
+        STA     $0725
+        LDX     #$0B            ; Store NOP's @ end
+        LDA     #$EA
+Y2K3    STA     $0732,X         
+        DEX     
+        BPL     Y2K3
+        LDA     #$60            ; Store RTS opcode @ end
+        STA     $0750
+        JSR     $0600           ; Show title screen
+        LDY     #$00            ; Clear RAM from $0600-$3FFF
+        STY     $80
+        LDA     #$06
+        STA     $81
+        JSR     CLRRAM
+        RTS     
+