Fix CPUID instruction test; old test only did 386 detection and

omitted 486 detection.

diff --git a/v7/src/microcode/cmpauxmd/i386.m4 b/v7/src/microcode/cmpauxmd/i386.m4
index 1c8d03e9c365abf32825a4997626d108845ea3d9..3f592ccdefaa33b335246f4810609bf30fbe8ca5 100644 (file)
--- a/v7/src/microcode/cmpauxmd/i386.m4
+++ b/v7/src/microcode/cmpauxmd/i386.m4
@@ -1,6 +1,6 @@
 ### -*-Midas-*-
 ###
-### $Id: i386.m4,v 1.62 2003/05/17 20:55:45 cph Exp $
+### $Id: i386.m4,v 1.63 2003/10/31 20:45:35 cph Exp $
 ###
 ### Copyright 1992,1997,1998,2000,2001 Massachusetts Institute of Technology
 ### Copyright 2002,2003 Massachusetts Institute of Technology
@@ -389,11 +389,14 @@ i386_initialize_no_fp:
        OP(mov,l)       TW(REG(eax),ABS(EVR(i387_presence)))
 
 # Do a bunch of hair to determine if we need to do cache synchronization.
-# First, test to see if the CPUID instruction is supported.
+# See if the CPUID instruction is supported.
 
        OP(xor,l)       TW(REG(eax),REG(eax))
        OP(mov,l)       TW(REG(eax),ABS(EVR(ia32_cpuid_supported)))
        OP(mov,l)       TW(REG(eax),ABS(EVR(ia32_cpuid_needed)))
+
+# First test: can we toggle the AC bit?
+
        pushfd
        OP(pop,l)       REG(eax)
        OP(mov,l)       TW(REG(eax),REG(ecx))
@@ -402,12 +405,28 @@ i386_initialize_no_fp:
        popfd
        pushfd
        OP(pop,l)       REG(eax)
+
+# if AC bit can't be toggled, this is a 386 (and doesn't support CPUID).
+
        OP(xor,l)       TW(REG(ecx),REG(eax))
        jz              no_cpuid_instr
+       OP(push,l)      REG(ecx)                        # restore EFLAGS
+       popfd
 
-# Restore original EFLAGS.
+# Now test to see if the ID bit can be toggled.
 
-       OP(push,l)      REG(ecx)
+       OP(mov,l)       TW(REG(ecx),REG(eax))
+       OP(xor,l)       TW(IMM(HEX(00200000)),REG(eax))
+       OP(push,l)      REG(eax)
+       popfd
+       pushfd
+       OP(pop,l)       REG(eax)
+
+# if ID bit can't be toggled, this is a 486 that doesn't support CPUID.
+
+       OP(xor,l)       TW(REG(ecx),REG(eax))
+       jz              no_cpuid_instr
+       OP(push,l)      REG(ecx)                        # restore EFLAGS
        popfd
 
 # Now we know that cpuid is supported.