Re: [Qemu-devel] x86 MMX register access problem seen on Sparc host

[malc]

On Mon, 22 Sep 2008, malc wrote:

> On Sun, 21 Sep 2008, Blue Swirl wrote:
>
> > Hi,
> >
> > I get these warnings when compiling i386 targets on Sparc host using a
> > gcc 4.3 series compiler:
> > /src/qemu/target-i386/ops_sse.h: In function 'helper_pmovmskb_mmx':
> > /src/qemu/target-i386/ops_sse.h:982: warning: array subscript is above
> > array bounds
> > etc.
> >
> > The first line is the following:
> >    val |= (s->XMM_B(0) >> 7);
>
> All the lines before #if SHIFT == 1 should be MMX_B really.

Scratch that. It should be this instead:

diff --git a/target-i386/ops_sse.h b/target-i386/ops_sse.h
index 7568681..2b594db 100644
--- a/target-i386/ops_sse.h
+++ b/target-i386/ops_sse.h
@@ -979,23 +979,23 @@ uint32_t glue(helper_pmovmskb, SUFFIX)(Reg *s)
 {
     uint32_t val;
     val = 0;
-    val |= (s->XMM_B(0) >> 7);
-    val |= (s->XMM_B(1) >> 6) & 0x02;
-    val |= (s->XMM_B(2) >> 5) & 0x04;
-    val |= (s->XMM_B(3) >> 4) & 0x08;
-    val |= (s->XMM_B(4) >> 3) & 0x10;
-    val |= (s->XMM_B(5) >> 2) & 0x20;
-    val |= (s->XMM_B(6) >> 1) & 0x40;
-    val |= (s->XMM_B(7)) & 0x80;
+    val |= (s->B(0) >> 7);
+    val |= (s->B(1) >> 6) & 0x02;
+    val |= (s->B(2) >> 5) & 0x04;
+    val |= (s->B(3) >> 4) & 0x08;
+    val |= (s->B(4) >> 3) & 0x10;
+    val |= (s->B(5) >> 2) & 0x20;
+    val |= (s->B(6) >> 1) & 0x40;
+    val |= (s->B(7)) & 0x80;
 #if SHIFT == 1
-    val |= (s->XMM_B(8) << 1) & 0x0100;
-    val |= (s->XMM_B(9) << 2) & 0x0200;
-    val |= (s->XMM_B(10) << 3) & 0x0400;
-    val |= (s->XMM_B(11) << 4) & 0x0800;
-    val |= (s->XMM_B(12) << 5) & 0x1000;
-    val |= (s->XMM_B(13) << 6) & 0x2000;
-    val |= (s->XMM_B(14) << 7) & 0x4000;
-    val |= (s->XMM_B(15) << 8) & 0x8000;
+    val |= (s->B(8) << 1) & 0x0100;
+    val |= (s->B(9) << 2) & 0x0200;
+    val |= (s->B(10) << 3) & 0x0400;
+    val |= (s->B(11) << 4) & 0x0800;
+    val |= (s->B(12) << 5) & 0x1000;
+    val |= (s->B(13) << 6) & 0x2000;
+    val |= (s->B(14) << 7) & 0x4000;
+    val |= (s->B(15) << 8) & 0x8000;
 #endif
     return val;
 }

> > In cpu.h, the macro is defined on big endian host as
> > #define XMM_B(n) _b[15 - (n)]
> >
> > But the type of Reg argument is MMXReg for pmovmskb_mmx and then the
> > _b array has only 8 items.

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