From 63ac7e42bd2aefab3ae00c0f5a81dffdf3c102db Mon Sep 17 00:00:00 2001
From: Astrid Smith
Date: Tue, 7 Sep 2010 19:12:01 -0700
Subject: IO port framework now works

A68k is defaulting all my address moves to word size, rather than
long.  I don't know whether I've expunged all this nonsense yet, but
I'm trying.

This version executes an infinite loop which writes 'A' to port 00h.
I've patched in a write-to-console function on port 00h, so this can
be used as a sort of debug monitor.
---
 ports.asm | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

(limited to 'ports.asm')

diff --git a/ports.asm b/ports.asm
index 5834ae5..c7b43e4 100644
--- a/ports.asm
+++ b/ports.asm
@@ -4,7 +4,10 @@
 	;; Port is in d0, byte is in d1
 	;; Destroys a0
 port_in:
-	movea	lut_ports_in(pc,d0),a0
+	andi.w	#$ff,d0
+	add.w	d0,d0
+	add.w	d0,d0
+	movea.l	lut_ports_in(pc,d0),a0
 	jmp	(a0)
 	rts
 
@@ -267,7 +270,10 @@ lut_ports_in:
 	dc.l	port_in_ff
 
 port_out:
-	movea	lut_ports_out(pc,d0.w),a0
+	andi.w	#$ff,d0
+	add.w	d0,d0
+	add.w	d0,d0
+	movea.l	lut_ports_out(pc,d0.w),a0
 	jmp	(a0)
 	rts
 
@@ -531,6 +537,16 @@ lut_ports_out:
 
 port_in_00:
 port_out_00:
+	;; Temporary test harness.  Writing to this port writes a
+	;; character to the screen.
+	SAVEREG
+	andi.w	#$ff,d1
+	move.w	d1,-(sp)
+	jsr	char_draw
+	addq	#2,sp
+	RESTREG
+	rts
+
 port_in_01:
 port_out_01:
 port_in_02:
-- 
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