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From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 4/5] ARM: entry: Remove unnecessary masking when decoding Thumb-2 instructions
Date: Wed, 10 Aug 2011 11:13:42 +0100	[thread overview]
Message-ID: <1312971223-28165-5-git-send-email-dave.martin@linaro.org> (raw)
In-Reply-To: <1312971223-28165-1-git-send-email-dave.martin@linaro.org>

When testing whether a Thumb-2 instruction is 32 bits long or not,
the masking done in order to test bits 11-15 of the first
instruction halfword won't affect the result of the comparison, so
remove it.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
---
 arch/arm/kernel/entry-armv.S |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index a87cbf8..b7236d4 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -262,8 +262,7 @@ __und_svc:
 	ldr	r0, [r4, #-4]
 #else
 	ldrh	r0, [r4, #-2]			@ Thumb instruction at LR - 2
-	and	r9, r0, #0xf800
-	cmp	r9, #0xe800			@ 32-bit instruction if xx >= 0
+	cmp	r0, #0xe800			@ 32-bit instruction if xx >= 0
 	ldrhhs	r9, [r4]			@ bottom 16 bits
 	orrhs	r0, r9, r0, lsl #16
 #endif
@@ -445,8 +444,7 @@ __und_usr:
  ARM(	ldrht	r5, [r4], #2	)
  THUMB(	ldrht	r5, [r4]	)
  THUMB(	add	r4, r4, #2	)
-	and	r0, r5, #0xf800			@ mask bits 111x x... .... ....
-	cmp	r0, #0xe800			@ 32bit instruction if xx != 0
+	cmp	r5, #0xe800			@ 32bit instruction if xx != 0
 	blo	__und_usr_unknown
 3:	ldrht	r0, [r4]
 	add	r2, r2, #2			@ r2 is PC + 2, make it PC + 4
-- 
1.7.4.1

  parent reply	other threads:[~2011-08-10 10:13 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-10 10:13 [RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels Dave Martin
2011-08-10 10:13 ` [RFC PATCH 1/5] ARM: Make cpu_alignment into a global variable Dave Martin
2011-08-10 11:38   ` Tixy
2011-08-10 10:13 ` [RFC PATCH 2/5] ARM: s3c24xx: Reference cpu_architecture as " Dave Martin
2011-08-10 10:13 ` [RFC PATCH 3/5] ARM: kprobes: " Dave Martin
2011-08-10 11:43   ` Tixy
2011-08-10 10:13 ` Dave Martin [this message]
2011-08-10 10:13 ` [RFC PATCH 5/5] ARM: entry: Fix Thumb-2 undef handling for multi-CPU kernels Dave Martin
2011-08-10 11:55   ` Tixy
2011-08-11 13:04     ` Dave Martin
2011-09-01 14:52   ` Arnd Bergmann
2011-09-07 10:54     ` Dave Martin
2011-09-12 10:33     ` Dave Martin
2011-08-10 11:31 ` [RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels Tixy
2011-08-11 13:10   ` Dave Martin
2011-08-15 23:13     ` Nicolas Pitre
2011-08-16  9:04       ` Dave Martin

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