# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1456157230 -3600
# Node ID a34a56734b6e1184fd9b9c3a39434bec11037edf
# Parent  f1919a78c1686dc82b9a4797845ad27d0f286cb0
Mask interrupts while handling them, saving the status and EPC registers.

diff -r f1919a78c168 -r a34a56734b6e stage2/handlers.S
--- a/stage2/handlers.S	Wed Jan 27 15:51:32 2016 +0100
+++ b/stage2/handlers.S	Mon Feb 22 17:07:10 2016 +0100
@@ -2,7 +2,7 @@
  * Handler routines.
  *
  * Copyright (C) 2015 Nicholas FitzRoy-Dale <wzdd.code@lardcave.net>
- * Copyright (C) 2015 Paul Boddie <paul@boddie.org.uk>
+ * Copyright (C) 2015, 2016 Paul Boddie <paul@boddie.org.uk>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -25,6 +25,15 @@
 .set noat
 
 interrupt_handler:
+
+	/* Save the status, mask interrupts. */
+
+	mfc0 $k0, $12 /* CP0_STATUS */
+	li $k1, 0xffff03ff
+	and $k1, $k0, $k1
+	mtc0 $k1, $12
+	sw $k0, -120($sp)
+
 	sw $at, -4($sp)
 	sw $v0, -8($sp)
 	sw $v1, -12($sp)
@@ -54,14 +63,18 @@
 	sw $fp, -108($sp)
 	sw $ra, -112($sp)
 
-	addi $sp, $sp, -112
+	mfc0 $k0, $14 /* CP0_EPC */
+	nop
+	sw $k0, -116($sp)
+
+	addi $sp, $sp, -120
 
 	/* Invoke the handler. */
 
 	jal     irq_handle
 	nop
 
-	addi $sp, $sp, 112
+	addi $sp, $sp, 120
 
 	lw $at, -4($sp)
 	lw $v0, -8($sp)
@@ -92,6 +105,14 @@
 	lw $fp, -108($sp)
 	lw $ra, -112($sp)
 
+	lw $k0, -116($sp)
+	mtc0 $k0, $14 /* CP0_EPC */
+	nop
+
+	lw $k0, -120($sp)
+	mtc0 $k0, $12 /* CP0_STATUS */
+	nop
+
 	eret
 	nop