add Atari TGI drivers from Fatih Aygun

git-svn-id: svn://svn.cc65.org/cc65/trunk@4456 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/atari/atari-4.s

@@ -0,0 +1,85 @@
+;
+; Graphics driver for the 80x48x2 (CIO mode 4, ANTIC mode 9) on the Atari.
+;
+; Fatih Aygun (2009)
+;
+
+	.include	"atari.inc"
+	.include 	"zeropage.inc"
+
+	.include 	"tgi-kernel.inc"
+	.include        "tgi-mode.inc"
+	.include        "tgi-error.inc"
+
+	.macpack        generic
+
+; ******************************************************************************
+
+	; ----------------------------------------------------------------------
+	;
+	; Constants and tables
+	;
+	; ----------------------------------------------------------------------
+
+; Graphics mode
+	.define grmode 4
+; X resolution
+	.define x_res 80
+; Y resolution
+	.define y_res 48
+; Number of colors
+	.define	colors 2
+; Pixels per byte
+	.define	ppb 8
+; Screen memory size in bytes
+	.define	scrsize x_res * y_res / ppb
+; Pixel aspect ratio
+	.define	aspect $0100				; 1:1
+; Free memory needed
+	.define	mem_needed 1
+; Number of screen pages
+	.define	pages 1
+
+.rodata
+	mask_table:				; Mask table to set pixels
+		.byte	%10000000, %01000000, %00100000, %00010000, %00001000, %00000100, %00000010, %00000001
+	masks:					; Color masks
+		.byte	%00000000, %11111111
+	bar_table:				; Mask table for BAR
+		.byte	%11111111, %01111111, %00111111, %00011111, %00001111, %00000111, %00000011, %00000001, %00000000
+	default_palette:
+		.byte	$00, $0E
+
+.code
+
+; ******************************************************************************
+
+.proc SETPALETTE
+
+	; ----------------------------------------------------------------------
+	;
+	; SETPALETTE: Set the palette (in ptr1)
+	;
+	; ----------------------------------------------------------------------
+
+.code
+	; Copy the palette
+	ldy     #colors - 1
+loop:	lda     (ptr1),y
+	sta     palette,y
+	dey
+	bpl     loop
+
+	; Get the color entries from the palette
+	lda	palette
+	sta	COLOR4
+	lda	palette + 1
+	sta	COLOR0
+
+	; Done, reset the error code
+        lda     #TGI_ERR_OK
+        sta     error
+        rts
+.endproc
+
+.include "atari_tgi_common.inc"