make sure that the cpuid of the simulated CPUID doesn't pretend

to support 3dnow!

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@1707

diff --git a/coregrind/vg_helpers.S b/coregrind/vg_helpers.S
index 6c1e40c09d3034dc8e750c8d39d3cb2890a45728..2edfeed828e6857e8e57a99031e46da52aaa2387 100644 (file)
--- a/coregrind/vg_helpers.S
+++ b/coregrind/vg_helpers.S
@@ -112,17 +112,18 @@ VG_(helper_RDTSC):
        dummy, replaced by %EDX value
        RA   <- %esp
 
-   As emulating a real CPUID is kinda hard, as it
-   has to return different values depending on EAX, 
-   we just pretend to not support CPUID at all until
-   it becomes a problem. This will for sure disable
-   all MMX / 3dnow checks so they don't bother us
-   with code we don't understand. (Dirk <dirk@kde.org>)
-   
+   For simulating the cpuid instruction, we will
+   issue a "real" cpuid instruction and then mask out
+   the bits of the features we do not support currently (3dnow mostly).
+
+   Dirk Mueller <mueller@kde.org>
+
    http://www.sandpile.org/ia32/cpuid.htm
 
-   (Later: we instead pretend to be like Werner's P54C P133, that is
-    an original pre-MMX Pentium).
+   references: 
+
+   pre-MMX pentium:
+
    <werner> cpuid words (0): 0x1 0x756e6547 0x6c65746e 0x49656e69
    <werner> cpuid words (1): 0x52b 0x0 0x0 0x1bf
 */
@@ -134,33 +135,23 @@ VG_(helper_CPUID):
        pushl   %edx
        movl    32(%esp), %eax
 
-       cpuid
+        cmpl   $0x80000001, %eax
+        je     cpuid_no3dnow
 
-/*
-        xor     %eax,%eax
-        xor     %ebx,%ebx
-        xor     %ecx,%ecx
-        xor     %edx,%edx
-*/
-/*
-       cmpl    $0, %eax
-       jz      cpuid__0
-       movl    $0x52b, %eax
-       movl    $0x0,   %ebx
-       movl    $0x0,   %ecx
-       movl    $0x008001bf, %edx
+       cpuid
        jmp     cpuid__99
-cpuid__0:
-       movl    $0x1,        %eax
-       movl    $0x756e6547, %ebx
-       movl    $0x6c65746e, %ecx
-       movl    $0x49656e69, %edx
+
+cpuid_no3dnow:
+       cpuid
+       
+       andl    $0x3fffffff, %edx
+
 cpuid__99:
-*/     
        movl    %edx, 20(%esp)
        movl    %ecx, 24(%esp)
        movl    %ebx, 28(%esp)
        movl    %eax, 32(%esp)
+
        popl    %edx
        popl    %ecx
        popl    %ebx