Added video routines, in C

4 files changed, 99 insertions, 39 deletions

diff --git a/main.asm b/main.asm
index 26aea4b..d91cde0 100644
--- a/main.asm
+++ b/main.asm
@@ -43,7 +43,7 @@
 
 	xdef	_ti89
 ;	xdef	_ti92plus
-	xdef	_main
+	xdef	__main
 	xdef	_nostub
 	include "../tios.h"
 
@@ -218,25 +218,15 @@ F_DEC_W	MACRO
 	;; I might be able to unify rotation flags or maybe use a
 	;; lookup table
 
-;;; one-off flag operations:
-;;; CCF - invert CARRY
-;;; CPL - H,N=1
-;;; RLD
-;;; 
 
 
-
-
-
-
-_main:
+__main:
 	movem.l d0-d7/a0-a6,-(sp)
 	bsr	emu_setup
 	movem.l (sp)+,d0-d7/a0-a6
 	rts
 
 	include	"ports.asm"
-	include	"video.asm"
 	include "interrupts.asm"
 	include	"flags.asm"
 
diff --git a/ports.asm b/ports.asm
index 056cd82..32a4a94 100644
--- a/ports.asm
+++ b/ports.asm
@@ -562,13 +562,23 @@ port_out_0e:
 port_in_0f:
 port_out_0f:
 port_in_10:
+	xref	video_row
+	xref	video_increment
+	xref	video_enabled
+	xref	video_6bit
+	xref	video_busy
+	xref	video_cur_row
+	xref	video_cur_col
+	xref	video_write
+	xref	video_read
+
 	;; LCD status
 	clr.b	d1
-	or.b	video_increment(pc),d1
-	or.b	video_row(pc),d1
-	or.b	video_enabled(pc),d1
-	or.b	video_6bit(pc),d1
-	or.b	video_busy(pc),d1
+	or.b	video_increment,d1
+	or.b	video_row,d1
+	or.b	video_enabled,d1
+	or.b	video_6bit,d1
+	or.b	video_busy,d1
 	rts
 
 port_out_10:
@@ -653,10 +663,13 @@ port_out_10_set_row:
 
 port_in_11:
 	;; LCD data
-	bra	video_read
+	jsr	video_read
+	move.b	d0,d1		; return value
+	rts
 
 port_out_11:
 	;; LCD data
+	move.b	d1,(a7)+
 	bra	video_write
 
 port_in_12:
diff --git a/video.asm b/video.asm
deleted file mode 100644
index b47d06c..0000000
--- a/video.asm
+++ /dev/null
@@ -1,21 +0,0 @@
-
-
-video_row:	dc.b	0	; $01 if in row mode - x
-				; $00 if in column mode - y
-video_increment:	dc.b	0	; $02 if in increment mode
-				; $00 if in decrement mode
-video_enabled:	dc.b	0	; $20 if screen is blanked
-video_6bit:	dc.b	0	; $40 if in 8 bit mode, $00 if in 6
-				; bit mode
-video_busy:	dc.b	0	; always 0
-
-video_cur_row:	dc.b	0
-video_cur_col:	dc.b	0
-
-	EVEN
-
-video_read:
-	rts
-
-video_write:
-	rts
diff --git a/video.c b/video.c
new file mode 100644
index 0000000..ee53ea4
--- /dev/null
+++ b/video.c
@@ -0,0 +1,78 @@
+/* LCD controller driver for 680 project.
+ *
+ * Copyright 2010, Duncan Smith
+ * GPL
+ */
+
+#include <graph.h>
+#include <nostub.h>
+
+#define VIDEO_ROWMODE 0x01
+#define VIDEO_COLMODE 0x00
+char video_row;
+
+#define VIDEO_AUTOINC 0x02
+#define VIDEO_AUTODEC 0x00
+char video_increment;
+
+#define VIDEO_ENABLED 0x00
+#define VIDEO_DISABLED 0x20
+char video_enabled;
+
+#define VIDEO_6BIT 0x00
+#define VIDEO_8BIT 0x40
+char video_6bit;
+
+char video_busy;        // Always 0
+
+char video_cur_row;
+char video_cur_col;
+
+void video_write(char);
+char video_read(void);
+void *video_compute_address(void);
+int video_compute_shift(void);
+
+void video_write(char data)
+{
+	int shift = video_compute_shift();
+	short int data_mask = ~(0xff00 >> shift);
+	short int data_dat = data >> (shift-8);
+	void *addr = video_compute_address();
+	*((short int *)addr) &= data_mask;
+	*((short int *)addr) |= data_dat;
+	return;
+}
+
+char video_read(void)
+{
+	int shift = video_compute_shift();
+	void *addr = video_compute_address();
+	short int data = *((short int *)addr);
+	data <<= (shift-8);
+	data &= 0xff;
+	return;
+}
+
+void *video_compute_address()
+{
+	void *addr;
+	int off;
+
+	addr = LCD_MEM;
+	addr += (video_cur_row) * (240 / 8);
+
+	if (video_6bit == VIDEO_6BIT)
+		off = video_cur_col * 6 / 8;
+	else
+		off = video_cur_col;
+	return addr + off;
+}
+
+int video_compute_shift()
+{
+	if (video_6bit == VIDEO_8BIT)
+		return 0;
+
+	return (video_cur_col * 6) % 8;
+}