# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1510061913 -3600
# Node ID 0c6e88eb049f2a1f53ee953f65dd66fd923b904a
# Parent  aa1ac5755f03bf3efe9250987736d16821f43a8c
Reordered channel and timer activation instructions, tidied generally.

diff -r aa1ac5755f03 -r 0c6e88eb049f vga.S
--- a/vga.S	Tue Nov 07 14:04:29 2017 +0100
+++ b/vga.S	Tue Nov 07 14:38:33 2017 +0100
@@ -554,8 +554,9 @@
 	DCHxDSIZ<15:0> = CHDSIZ<15:0> = 1
 	*/
 
+	li $v1, 1
+
 	la $v0, DCH0DSIZ
-	li $v1, 1
 	sw $v1, 0($v0)
 
 	la $v0, DCH1DSIZ
@@ -566,10 +567,11 @@
 	DCHxDSA = physical(PORTB)
 	*/
 
-	la $v0, DCH0DSA
 	li $v1, PORTB
 	li $t8, KSEG1_BASE
 	subu $v1, $v1, $t8
+
+	la $v0, DCH0DSA
 	sw $v1, 0($v0)
 
 	la $v0, DCH1DSA
@@ -589,8 +591,6 @@
 	la $v0, IPC10
 	li $v1, 0b11111		/* DMA0IP, DMA0IS = 0 */
 	sw $v1, CLR($v0)
-
-	la $v0, IPC10
 	li $v1, 0b11111		/* DMA0IP = 7, DMA0IS = 3 */
 	sw $v1, SET($v0)
 
@@ -883,12 +883,6 @@
 	la $v0, DCH0SSA
 	sw $s2, 0($v0)
 
-	/* Enable the line channel for timer event transfer initiation. */
-
-	la $v0, DCH0ECON
-	li $v1, (1 << 4)	/* DCH0ECON<4> = SIRQEN = 1 */
-	sw $v1, SET($v0)
-
 	/*
 	Suspend delivery of the timer interrupt during the visible period.
 	The condition still occurs, however.
@@ -908,6 +902,12 @@
 	li $v1, (1 << 9)
 	sw $v1, SET($v0)	/* T2IE = 0 */
 
+	/* Enable the line channel for timer event transfer initiation. */
+
+	la $v0, DCH0ECON
+	li $v1, (1 << 4)	/* DCH0ECON<4> = SIRQEN = 1 */
+	sw $v1, SET($v0)
+
 _vbp_active_ret:
 	jr $ra
 	nop