From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: scottwood@freescale.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 10/21] powerpc/8xx: Duplicate two insns instead of branching
Date: Fri, 19 Sep 2014 10:36:08 +0200 (CEST) [thread overview]
Message-ID: <20140919083608.6C7BA1AB03B@localhost.localdomain> (raw)
Branching takes two cycles on MPC8xx. Lets duplicate the two instructions
and avoid the branching.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
Changes in v2:
- None
Changes in v3:
- None
Changes in v4:
- None
arch/powerpc/kernel/head_8xx.S | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 5037420..4a49ff3 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -638,9 +638,11 @@ modified_instr:
/* special handling for r10,r11 since these are modified already */
153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */
- b 155f
+ add r10, r10, r11 /* add it */
+ mfctr r11 /* restore r11 */
+ b 151b
154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */
-155: add r10, r10, r11 /* add it */
+ add r10, r10, r11 /* add it */
mfctr r11 /* restore r11 */
b 151b
#endif
--
1.7.1
WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Joakim Tjernlund <joakim.tjernlund@transmode.se>,
scottwood@freescale.com
Subject: [PATCH v4 10/21] powerpc/8xx: Duplicate two insns instead of branching
Date: Fri, 19 Sep 2014 10:36:08 +0200 (CEST) [thread overview]
Message-ID: <20140919083608.6C7BA1AB03B@localhost.localdomain> (raw)
Branching takes two cycles on MPC8xx. Lets duplicate the two instructions
and avoid the branching.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
Changes in v2:
- None
Changes in v3:
- None
Changes in v4:
- None
arch/powerpc/kernel/head_8xx.S | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 5037420..4a49ff3 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -638,9 +638,11 @@ modified_instr:
/* special handling for r10,r11 since these are modified already */
153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */
- b 155f
+ add r10, r10, r11 /* add it */
+ mfctr r11 /* restore r11 */
+ b 151b
154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */
-155: add r10, r10, r11 /* add it */
+ add r10, r10, r11 /* add it */
mfctr r11 /* restore r11 */
b 151b
#endif
--
1.7.1
next reply other threads:[~2014-09-19 8:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-19 8:36 Christophe Leroy [this message]
2014-09-19 8:36 ` [PATCH v4 10/21] powerpc/8xx: Duplicate two insns instead of branching Christophe Leroy
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