[PULL,01/41] target/arm: Fix sign-extension for SMLAL*

Message ID 20191022133134.14487-2-peter.maydell@linaro.org
State Not Applicable
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Series
  • target-arm queue
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Commit Message

Peter Maydell Oct. 22, 2019, 1:30 p.m.
From: Richard Henderson <richard.henderson@linaro.org>


The 32-bit product should be sign-extended, not zero-extended.

Fixes: ea96b374641b
Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>

Message-id: 20190912183058.17947-1-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

---
 target/arm/translate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.20.1

Patch

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 698c594e8ce..96340520ee2 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -8045,7 +8045,9 @@  static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
     case 2:
         tl = load_reg(s, a->ra);
         th = load_reg(s, a->rd);
-        t1 = tcg_const_i32(0);
+        /* Sign-extend the 32-bit product to 64 bits.  */
+        t1 = tcg_temp_new_i32();
+        tcg_gen_sari_i32(t1, t0, 31);
         tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
         tcg_temp_free_i32(t0);
         tcg_temp_free_i32(t1);