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From: Peng Fan <Peng.Fan@freescale.com>
To: xen-devel@lists.xen.org
Cc: Julien Grall <julien.grall@citrix.com>,
	Peng.Fan@freescale.com,
	Stefano Stabellini <stefano.stabellini@citrix.com>,
	Ian Campbell <ian.campbell@citrix.com>
Subject: [PATCH 2/2] xen: arm: traps: correct cond
Date: Mon, 21 Sep 2015 15:07:56 +0800	[thread overview]
Message-ID: <1442819276-25437-1-git-send-email-Peng.Fan@freescale.com> (raw)

>From "G6.2.29 CPSR, Current Program Status Register" of Aarch64 ARM
and "B1.3.3 Program Status Registers (PSRs)" of ARMv7-A ARM:
"
IT[7:5] holds the base condition for the IT block. The base condition is
        the top 3 bits of the condition code specified by the first
	condition field of the IT instruction.
IT[4:0] encodes the size of the IT block, which is the number of
        instructions that are to be conditionally executed, by the
	position of the least significant 1 in this field. It also
	encodes the value of the least significant bit of the condition
	code for each instruction in the block.
"

So should be "cond = ( it >> 5 );" but not "cond = ( it >> 4 );"

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@citrix.com>
Cc: Julien Grall <julien.grall@citrix.com>
---
 xen/arch/arm/traps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 2e2b1f2..b2879b7 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1561,8 +1561,8 @@ static int check_conditional_instr(struct cpu_user_regs *regs,
         if ( it == 0 )
             return 1;
 
-        /* The cond for this instruction works out as the top 4 bits. */
-        cond = ( it >> 4 );
+        /* The cond for this instruction works out as the top 3 bits. */
+        cond = ( it >> 5 );
     }
 
     cpsr_cond = cpsr >> 28;
-- 
1.8.4

             reply	other threads:[~2015-09-21  7:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-21  7:07 Peng Fan [this message]
2015-09-21 10:10 ` [PATCH 2/2] xen: arm: traps: correct cond Julien Grall
2015-09-21  9:08   ` Peng Fan
2015-09-21 10:33     ` Ian Campbell
2015-09-22  0:46       ` Peng Fan

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