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[Qemu-devel] [PATCH] target-arm/translate: Fix RRX operands


From: Peter Crosthwaite
Subject: [Qemu-devel] [PATCH] target-arm/translate: Fix RRX operands
Date: Tue, 16 Oct 2012 19:15:50 +1000

Instructions that both use the RRX second operand and update CS were
incorrect, as the Carry flag was updated too early. An example of such an
instruction would be:

ands r12,r13,RRX

Ands, because of the "s" flag will update the carry flag. But the RRX second
operand rotates through the C flag which should happen before the update.
Fixed the ordering of the two, the old carry is read by "r13,RRX" before being
updated.

Signed-off-by: Peter Crosthwaite <address@hidden>
Reported-by: Vinesh Peringat <address@hidden>
---
 target-arm/translate.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index c6840b7..daccb15 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -516,10 +516,10 @@ static inline void gen_arm_shift_im(TCGv var, int 
shiftop, int shift, int flags)
             tcg_gen_rotri_i32(var, var, shift); break;
         } else {
             TCGv tmp = tcg_temp_new_i32();
+            tcg_gen_shli_i32(tmp, cpu_CF, 31);
             if (flags)
                 shifter_out_im(var, 0);
             tcg_gen_shri_i32(var, var, 1);
-            tcg_gen_shli_i32(tmp, cpu_CF, 31);
             tcg_gen_or_i32(var, var, tmp);
             tcg_temp_free_i32(tmp);
         }
-- 
1.7.0.4




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