Added VIC-20 6560 Chip Include File

vic20/include/vic6560.a02

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+; VIC-20 Assembly Language Routines for VIC 6560 Chip
+
+;VIC Chip Registers
+VICSCH  EQU $9000 ;Interlace Mode + Horizontal Screen Origin
+VICSCV  EQU $9001 ;Vertical Screen Origin
+VICCOL  EQU $9002 ;Screen Memory Location + Number of Video Columns
+VICROW  EQU $9003 ;Raster Value + Number of Video Rows + Character Size
+VICRST  EQU $9004 ;Raster Value  
+VICLOC  EQU $9005 ;Screen Memory Location + Character Memory Location
+VICLPH  EQU $9006 ;Light Pen - Horizontal
+VICLPV  EQU $9007 ;Light Pen - Vertical
+VICPD1  EQU $9008 ;Paddle 1
+VICPD2  EQU $9009 ;Paddle 2
+VICBSF  EQU $900A ;Bass Sound Switch and Frequency
+VICASF  EQU $900B ;Alto Sound Switch and Frequency
+VICSSF  EQU $900C ;Soprano Sound Switch and Frequency
+VICNSF  EQU $900D ;Noise Switch and Frequency
+VICAVL  EQU $900E ;Auxillary Color + Sound Volume
+VICCLR  EQU $900F ;Screen Color + Reverse Mode + Border Color
+
+;Set Screen Origin and Interlace Mode
+;Args: A = Horizontal Screen Origin
+;      Y = Vertical Screen Origin
+;      X = Interlace Mode, 0=Off, !0=On
+SETORG: AND #$7F        ;Clear Accumulator High Bit
+        CPX #0          ;Test Interlace Mode
+        BEQ SETORH      ;If Not Zero
+        ORA #$80        ;  Set Accumulator High Bit
+        STA VICSCH      ;Write to Horizontal Origin Register
+        STY VICSCV      ;Write Y to Vertical Origin Register
+        RTS
+
+;Set Memory Locations and Number of Columns
+;Args: A = Screen Memory Address Offset
+       Y = Character Address Memory Offset
+       X = Number of Video Columns
+SETSCN: LSR             ;Roll Screen Offset Low Bit into Carry Flag
+        PHA             ;And Save Top Four Bits on Stack
+        TXA             ;Copy Columns into Accumulator
+        AND #$7F        ;Clear High Bit
+        BCC SETSCC      ;If Carry Set from Roll
+        ORA #$80        ;  Set High Bit
+        STA VICCOL      ;Write to Video Columns Register
+        PLA             ;Retrieve Screen Memory Offset
+        ASL             ;Shift to High Bit
+        ASL
+        ASL
+        ASL
+        PHA             ;And Push onto Stack
+        TYA             ;Put Character Address Offset in Accumulator
+        AND #$0F        ;Clear High Nybble
+        TSX             ;Get Index to Screen Address Offset
+        ORA $101,X      ;Load Into Accumulator High Nybble
+        STA VICLOC      ;Write to Memory Locations Register
+        PLA             ;Clean up Stack
+        RTS
+