From: Richard Henderson <richard.henderson@linaro.org>
Date: Tue, 22 Oct 2019 15:50:35 +0000 (+0100)
Subject: target/arm: Fix sign-extension for SMLAL*
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1ab170865202aab8301131f31bffd87ea0f60d16;p=qemu.git

target/arm: Fix sign-extension for SMLAL*

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>
---

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 698c594e8c..96340520ee 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);