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[Qemu-devel] [PATCH] mips: Fix BC1ANY[24]F instructions


From: Richard Sandiford
Subject: [Qemu-devel] [PATCH] mips: Fix BC1ANY[24]F instructions
Date: Sat, 26 Nov 2011 13:37:07 +0000
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux)

There's some dodgy application of De Morgan's law in the emulation
of the MIPS BC1ANY[24]F instructions: they end up branching only
if all CCs are false, rather than if one CC is.

Tested on mips64-linux-gnu, where it fixes the GCC MIPS3D tests.

Signed-off-by: Richard Sandiford <address@hidden>
---
 target-mips/translate.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/target-mips/translate.c b/target-mips/translate.c
index ba45eb0..2b977b3 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -6017,7 +6017,7 @@ static void gen_compute_branch1 (CPUState *env, 
DisasContext *ctx, uint32_t op,
             TCGv_i32 t1 = tcg_temp_new_i32();
             tcg_gen_shri_i32(t0, fpu_fcr31, get_fp_bit(cc));
             tcg_gen_shri_i32(t1, fpu_fcr31, get_fp_bit(cc+1));
-            tcg_gen_nor_i32(t0, t0, t1);
+            tcg_gen_nand_i32(t0, t0, t1);
             tcg_temp_free_i32(t1);
             tcg_gen_andi_i32(t0, t0, 1);
             tcg_gen_extu_i32_tl(bcond, t0);
@@ -6041,11 +6041,11 @@ static void gen_compute_branch1 (CPUState *env, 
DisasContext *ctx, uint32_t op,
             TCGv_i32 t1 = tcg_temp_new_i32();
             tcg_gen_shri_i32(t0, fpu_fcr31, get_fp_bit(cc));
             tcg_gen_shri_i32(t1, fpu_fcr31, get_fp_bit(cc+1));
-            tcg_gen_or_i32(t0, t0, t1);
+            tcg_gen_and_i32(t0, t0, t1);
             tcg_gen_shri_i32(t1, fpu_fcr31, get_fp_bit(cc+2));
-            tcg_gen_or_i32(t0, t0, t1);
+            tcg_gen_and_i32(t0, t0, t1);
             tcg_gen_shri_i32(t1, fpu_fcr31, get_fp_bit(cc+3));
-            tcg_gen_nor_i32(t0, t0, t1);
+            tcg_gen_nand_i32(t0, t0, t1);
             tcg_temp_free_i32(t1);
             tcg_gen_andi_i32(t0, t0, 1);
             tcg_gen_extu_i32_tl(bcond, t0);
-- 
1.7.2.5




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