[Qemu-devel] Mips 64 emulation not compiling

["J. Mayer" <l_indien@magic.fr>]

The latest patches in clo makes gcc 3.4.6 fail to build the mips64
targets on my amd64 host (looks like an register allocation clash in the
optimizer code).
Furthermore, the clz micro-op for Mips seems very suspect to me,
according to the changes made in the clo implementation.
I did change the clz / clo implementation to use the same code as the
one used for the PowerPC implementation. It seems to me that the result
would be correct... And it compiles...

Please take a look to the folowing patch:


Index: target-mips/op.c
===================================================================
RCS file: /sources/qemu/qemu/target-mips/op.c,v
retrieving revision 1.80
diff -u -d -d -p -r1.80 op.c
--- target-mips/op.c    24 Oct 2007 00:10:32 -0000      1.80
+++ target-mips/op.c    24 Oct 2007 10:38:26 -0000
@@ -535,37 +535,44 @@ void op_rotrv (void)
     RETURN();
 }
 
-void op_clo (void)
+static always_inline int _do_cntlzw (uint32_t val)
 {
-    int n;
-
-    if (T0 == ~((target_ulong)0)) {
-        T0 = 32;
-    } else {
-        for (n = 0; n < 32; n++) {
-            if (!(((int32_t)T0) & (1 << 31)))
-                break;
-            T0 <<= 1;
-        }
-        T0 = n;
+    int cnt = 0;
+    if (!(val & 0xFFFF0000UL)) {
+        cnt += 16;
+        val <<= 16;
+    }
+    if (!(val & 0xFF000000UL)) {
+        cnt += 8;
+        val <<= 8;
     }
+    if (!(val & 0xF0000000UL)) {
+        cnt += 4;
+        val <<= 4;
+    }
+    if (!(val & 0xC0000000UL)) {
+        cnt += 2;
+        val <<= 2;
+    }
+    if (!(val & 0x80000000UL)) {
+        cnt++;
+        val <<= 1;
+    }
+    if (!(val & 0x80000000UL)) {
+        cnt++;
+    }
+    return cnt;
+}
+
+void op_clo (void)
+{
+    T0 = _do_cntlzw(~T0);
     RETURN();
 }
 
 void op_clz (void)
 {
-    int n;
-
-    if (T0 == 0) {
-        T0 = 32;
-    } else {
-        for (n = 0; n < 32; n++) {
-            if (T0 & (1 << 31))
-                break;
-            T0 <<= 1;
-        }
-        T0 = n;
-    }
+    T0 = _do_cntlzw(T0);
     RETURN();
 }
 

-- 
J. Mayer <l_indien@magic.fr>
Never organized