Re: [Qemu-devel] [PATCH] target-mips: fix mipsdsp_mul_q15_q15 and tests for MAQ_SA_Q_PHL/PHR

[Petar Jovanovic]

There is a typo in the subject, it should say:

"target-mips: fix mipsdsp_mul_q15_q15 and tests for MAQ_SA_W_PHL/PHR"

Petar
________________________________________
From: Petar Jovanovic address@hidden
Sent: Monday, April 15, 2013 1:54 PM
To: address@hidden
Cc: Petar Jovanovic; address@hidden
Subject: [PATCH] target-mips: fix mipsdsp_mul_q15_q15 and tests for 
MAQ_SA_Q_PHL/PHR

From: Petar Jovanovic <address@hidden>

The operands for MAQ_SA_W.PHL/MAQ_SA_W.PHR must in specified format.
Otherwise, the results are unpredictable. Once the operands were corrected
in the tests (part of this change), a bug in mipsdsp_mul_q15_q15 became
visible.

This change corrects the tests for MAQ_SA_W.PHL/MAQ_SA_W.PHR and fixes
sign-related issue in mipsdsp_mul_q15_q15. It also removes unnecessary
comment.

Signed-off-by: Petar Jovanovic <address@hidden>
---
 target-mips/dsp_helper.c                 |   14 +-------------
 tests/tcg/mips/mips32-dsp/maq_sa_w_phl.c |   12 ++++++------
 tests/tcg/mips/mips32-dsp/maq_sa_w_phr.c |   24 ++++++++++++------------
 3 files changed, 19 insertions(+), 31 deletions(-)

diff --git a/target-mips/dsp_helper.c b/target-mips/dsp_helper.c
index c7df595..a368062 100644
--- a/target-mips/dsp_helper.c
+++ b/target-mips/dsp_helper.c
@@ -269,18 +269,6 @@ static inline int32_t mipsdsp_sat32_acc_q31(int32_t acc, 
int32_t a,
     temp31 = (temp_sum >> 31) & 0x01;
     result = temp_sum & 0xFFFFFFFF;

-    /* FIXME
-       This sat function may wrong, because user manual wrote:
-       temp127..0 ← temp + ( (signA) || a31..0
-       if ( temp32 ≠ temp31 ) then
-           if ( temp32 = 0 ) then
-               temp31..0 ← 0x80000000
-           else
-                temp31..0 ← 0x7FFFFFFF
-           endif
-           DSPControlouflag:16+acc ← 1
-       endif
-     */
     if (temp32 != temp31) {
         if (temp32 == 0) {
             result = 0x7FFFFFFF;
@@ -578,7 +566,7 @@ static inline int32_t mipsdsp_mul_q15_q15(int32_t ac, 
uint16_t a, uint16_t b,
         temp = 0x7FFFFFFF;
         set_DSPControl_overflow_flag(1, 16 + ac, env);
     } else {
-        temp = ((uint32_t)a * (uint32_t)b) << 1;
+         temp = ((int16_t)a * (int16_t)b) << 1;
     }

     return temp;
diff --git a/tests/tcg/mips/mips32-dsp/maq_sa_w_phl.c 
b/tests/tcg/mips/mips32-dsp/maq_sa_w_phl.c
index a756991..d83dce6 100644
--- a/tests/tcg/mips/mips32-dsp/maq_sa_w_phl.c
+++ b/tests/tcg/mips/mips32-dsp/maq_sa_w_phl.c
@@ -10,12 +10,12 @@ int main()
     int resulth, resultl;
     int resdsp;

-    achi = 0x05;
-    acli = 0xB4CB;
+    achi = 0x00000000;
+    acli = 0x0000B4CB;
     rs = 0xFF060000;
     rt = 0xCB000000;
-    resulth = 0x00;
-    resultl = 0x7FFFFFFF;
+    resulth = 0x00000000;
+    resultl = 0x006838CB;

     __asm
         ("mthi %2, $ac1\n\t"
@@ -29,8 +29,8 @@ int main()
     assert(resulth == acho);
     assert(resultl == aclo);

-    achi = 0x06;
-    acli = 0xB4CB;
+    achi = 0x00000000;
+    acli = 0x0000B4CB;
     rs  = 0x80000000;
     rt  = 0x80000000;
     resulth = 0x00;
diff --git a/tests/tcg/mips/mips32-dsp/maq_sa_w_phr.c 
b/tests/tcg/mips/mips32-dsp/maq_sa_w_phr.c
index d6498f8..d233111 100644
--- a/tests/tcg/mips/mips32-dsp/maq_sa_w_phr.c
+++ b/tests/tcg/mips/mips32-dsp/maq_sa_w_phr.c
@@ -10,12 +10,12 @@ int main()
     int resulth, resultl;
     int resdsp;

-    achi = 0x05;
-    acli = 0xB4CB;
-    rs  = 0xFF06;
-    rt  = 0xCB00;
-    resulth = 0x00;
-    resultl = 0x7FFFFFFF;
+    achi = 0x00000000;
+    acli = 0x0000B4CB;
+    rs  = 0x0000FF06;
+    rt  = 0x0000CB00;
+    resulth = 0x00000000;
+    resultl = 0x006838CB;

     __asm
         ("mthi %2, $ac1\n\t"
@@ -29,12 +29,12 @@ int main()
     assert(resulth == acho);
     assert(resultl == aclo);

-    achi = 0x06;
-    acli = 0xB4CB;
-    rs  = 0x8000;
-    rt  = 0x8000;
-    resulth = 0x00;
-    resultl = 0x7fffffff;
+    achi = 0x00000000;
+    acli = 0x0000B4CB;
+    rs  = 0x00008000;
+    rt  = 0x00008000;
+    resulth = 0x00000000;
+    resultl = 0x7FFFFFFF;
     resdsp = 0x01;

     __asm
--
1.7.9.5