Re: [Qemu-devel] [PATCH] target-mips: fix for incorrect multiplication with MULQ_S.PH

[Petar Jovanovic]

ping
http://patchwork.ozlabs.org/patch/218695/

________________________________________
From: Petar Jovanovic address@hidden
Sent: Wednesday, February 06, 2013 6:05 PM
To: address@hidden
Cc: Jovanovic, Petar; address@hidden
Subject: [PATCH] target-mips: fix for incorrect multiplication with MULQ_S.PH

From: Petar Jovanovic <address@hidden>

The change corrects sign-related issue with MULQ_S.PH. It also includes
extension to the already existing test which will trigger the issue.

Signed-off-by: Petar Jovanovic <address@hidden>
---
 target-mips/dsp_helper.c                |    2 +-
 tests/tcg/mips/mips32-dspr2/mulq_s_ph.c |   15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/target-mips/dsp_helper.c b/target-mips/dsp_helper.c
index 96cb044..6781da8 100644
--- a/target-mips/dsp_helper.c
+++ b/target-mips/dsp_helper.c
@@ -652,7 +652,7 @@ static inline int32_t mipsdsp_sat16_mul_q15_q15(uint16_t a, 
uint16_t b,
         temp = 0x7FFF0000;
         set_DSPControl_overflow_flag(1, 21, env);
     } else {
-        temp = ((uint32_t)a * (uint32_t)b);
+        temp = (int16_t)a * (int16_t)b;
         temp = temp << 1;
     }

diff --git a/tests/tcg/mips/mips32-dspr2/mulq_s_ph.c 
b/tests/tcg/mips/mips32-dspr2/mulq_s_ph.c
index d0f7674..00e0155 100644
--- a/tests/tcg/mips/mips32-dspr2/mulq_s_ph.c
+++ b/tests/tcg/mips/mips32-dspr2/mulq_s_ph.c
@@ -6,6 +6,21 @@ int main()
     int rd, rs, rt, dsp;
     int result, resultdsp;

+    rs = 0x80000000;
+    rt = 0x0ffc0000;
+    result = 0xF0040000;
+    resultdsp = 0;
+
+    __asm
+        ("mulq_s.ph %0, %2, %3\n\t"
+         "rddsp %1\n\t"
+         : "=r"(rd), "=r"(dsp)
+         : "r"(rs), "r"(rt)
+        );
+    dsp = (dsp >> 21) & 0x01;
+    assert(rd  == result);
+    assert(dsp == resultdsp);
+
     rs = 0x80001234;
     rt = 0x80004321;
     result = 0x7FFF098B;
--
1.7.9.5