From a8c6500fc3867a9fb6fb4cb59d62e844e7df9db1 Mon Sep 17 00:00:00 2001
From: Brett Gordon <beretta42@gmail.com>
Date: Fri, 9 Oct 2015 10:05:40 -0400
Subject: [PATCH] coco3: import of dragon's gfx code.

---
 Kernel/platform-coco3/videoll.s | 48 +++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/Kernel/platform-coco3/videoll.s b/Kernel/platform-coco3/videoll.s
index bbc0fe92..57c3fe1a 100644
--- a/Kernel/platform-coco3/videoll.s
+++ b/Kernel/platform-coco3/videoll.s
@@ -2,12 +2,21 @@
 ;;;  Low-Level Video Routines
 ;;;
 ;;;
+	.module	videoll
+
 
 	.globl	_memset
 	.globl	_memcpy
+
+	include "kernel.def"
+	include "../kernel09.def"
 	
 	.area .video
 
+VIDEO_BASE  equ	 $4000
+
+
+	
 ;;;   void *memset(void *d, int c, size_t sz)
 _memset:
 	pshs	x,y
@@ -30,3 +39,42 @@ a@	ldb	,u+
 	leay	-1,y
 	bne	a@
 	puls	x,y,u,pc
+
+
+
+
+vidptr:
+	ldu 	#VIDEO_BASE
+	ldd 	,x++		; Y into B
+	lda 	#32
+	mul
+	leau 	d,u
+	ldd 	,x++		; X
+	leau 	d,u
+	rts
+
+
+;;; void video_cmd( char *rle_data );
+_video_cmd:
+	pshs 	u
+	bsr 	vidptr		; u now points to the screen
+nextline:
+	pshs 	u		; save it for the next line
+nextop:
+	ldb 	,x+		; op code, 0 = end of line
+	beq 	endline
+oploop:
+	lda 	,u		; do one screen byte
+	anda 	,x
+	eora 	1,x
+	sta 	,u+
+	decb
+	bne 	oploop		; keep going for run
+	leax 	2,x
+	bra 	nextop		; next triplet
+endline:
+	puls 	u		; get position back
+	leau 	32,u		; down one scan line
+	ldb 	,x+		; get next op - 0,0 means end and done
+	bne 	oploop
+	puls 	u,pc
-- 
2.34.1