qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH v2] target-mips: fix EXTPDP and setting up pos field


From: Petar Jovanovic
Subject: [Qemu-devel] [PATCH v2] target-mips: fix EXTPDP and setting up pos field in the DSPControl reg
Date: Fri, 17 May 2013 19:45:58 +0200

From: Petar Jovanovic <address@hidden>

This change makes sure that modifications of pos field in the DSPControl
register do not trash other bits in the register. This bug can be triggered
with the additional test case in mips32-dsp/extpdp.c in this commit.

In addition to this, this change corrects incorrect calculation of the mask
for EXTPDP.

Signed-off-by: Petar Jovanovic <address@hidden>
---
 v2:
 - Update in helper_extpdp when passing pos value to set_DSPControl_pos.

 target-mips/dsp_helper.c           |    9 ++++-----
 tests/tcg/mips/mips32-dsp/extpdp.c |   18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/target-mips/dsp_helper.c b/target-mips/dsp_helper.c
index a55f866..49cdba1 100644
--- a/target-mips/dsp_helper.c
+++ b/target-mips/dsp_helper.c
@@ -90,10 +90,10 @@ static inline void set_DSPControl_pos(uint32_t pos, 
CPUMIPSState *env)
     dspc = env->active_tc.DSPControl;
 #ifndef TARGET_MIPS64
     dspc = dspc & 0xFFFFFFC0;
-    dspc |= pos;
+    dspc |= (pos & 0x3F);
 #else
     dspc = dspc & 0xFFFFFF80;
-    dspc |= pos;
+    dspc |= (pos & 0x7F);
 #endif
     env->active_tc.DSPControl = dspc;
 }
@@ -3439,10 +3439,9 @@ target_ulong helper_extpdp(target_ulong ac, target_ulong 
size,
     if (sub >= -1) {
         acc  = ((uint64_t)env->active_tc.HI[ac] << 32) |
                ((uint64_t)env->active_tc.LO[ac] & MIPSDSP_LLO);
-        temp = (acc >> (start_pos - size)) &
-               (((uint32_t)0x01 << (size + 1)) - 1);
+        temp = (acc >> (start_pos - size)) & (~0U >> (31 - size));
 
-        set_DSPControl_pos(start_pos - (size + 1), env);
+        set_DSPControl_pos(sub, env);
         set_DSPControl_efi(0, env);
     } else {
         set_DSPControl_efi(1, env);
diff --git a/tests/tcg/mips/mips32-dsp/extpdp.c 
b/tests/tcg/mips/mips32-dsp/extpdp.c
index 15ba082..79ee16e 100644
--- a/tests/tcg/mips/mips32-dsp/extpdp.c
+++ b/tests/tcg/mips/mips32-dsp/extpdp.c
@@ -42,5 +42,23 @@ int main()
     efi = (dsp >> 14) & 0x01;
     assert(efi == 1);
 
+
+    ach = 0;
+    acl = 0;
+    dsp = 0;
+    result = 0;
+
+    __asm
+        ("wrdsp %1\n\t"
+         "mthi %2, $ac1\n\t"
+         "mtlo %3, $ac1\n\t"
+         "extpdp %0, $ac1, 0x00\n\t"
+         "rddsp %1\n\t"
+         : "=r"(rt), "+r"(dsp)
+         : "r"(ach), "r"(acl)
+        );
+    assert(dsp == 0x3F);
+    assert(result == rt);
+
     return 0;
 }
-- 
1.7.9.5




reply via email to

[Prev in Thread] Current Thread [Next in Thread]