From e1e042445c3d0ad6e22119d119bf3a908e67fc79 Mon Sep 17 00:00:00 2001
From: bjh21 <bjh21@NetBSD.org>
Date: Thu, 18 Jan 2001 20:42:03 +0000
Subject: [PATCH] A bit of extra discussion based on the latest ARM ARM.

---
 sys/arch/arm/include/trap.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/sys/arch/arm/include/trap.h b/sys/arch/arm/include/trap.h
index b3b5687e54d9..71d44b823b1c 100644
--- a/sys/arch/arm/include/trap.h
+++ b/sys/arch/arm/include/trap.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: trap.h,v 1.1 2001/01/10 19:02:08 bjh21 Exp $	*/
+/*	$NetBSD: trap.h,v 1.2 2001/01/18 20:42:03 bjh21 Exp $	*/
 
 /*
  * Copyright (c) 1995 Mark Brinicombe.
@@ -47,6 +47,11 @@
  * needs an undefined instruction as a break point.
  * Ideally ARM would define several standard instruction
  * sequences for use as breakpoints.
+ * The BKPT instruction isn't much use to us, since its
+ * behaviour is unpredictable on ARMv3 and lower.
+ *
+ * The ARM ARM says that for maximum compatibility, we should use undefined
+ * instructions that look like 0x.7f...f. .
  */
 
 #define GDB_BREAKPOINT		0xe6000011	/* Used by GDB */