Better detection and implementation for cpuid instruction on Intel-derived processors, both 32-bit and 64-bit

3 files changed, 25 insertions, 17 deletions

diff --git a/unix/configure b/unix/configure
index df67e5d..522828d 100755
--- a/unix/configure
+++ b/unix/configure
@@ -18925,9 +18925,13 @@ int
 main ()
 {
 
-	int index,ax,bx,cx,dx;
-	__asm__ __volatile__ ("cpuid":\
-	"=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (index));
+	int index,regsPtr[4];
+    __asm__ __volatile__("mov %%ebx, %%edi     \n\t"
+                 "cpuid            \n\t"
+                 "mov %%ebx, %%esi   \n\t"
+                 "mov %%edi, %%ebx  \n\t"
+                 : "=a"(regsPtr[0]), "=S"(regsPtr[1]), "=c"(regsPtr[2]), "=d"(regsPtr[3])
+                 : "a"(index));
 
   ;
   return 0;
@@ -18968,7 +18972,8 @@ fi
 echo "$as_me:$LINENO: result: $tcl_cv_cpuid" >&5
 echo "${ECHO_T}$tcl_cv_cpuid" >&6
 if test $tcl_cv_cpuid = yes; then
-    cat >>confdefs.h <<\_ACEOF
+
+cat >>confdefs.h <<\_ACEOF
 #define HAVE_CPUID 1
 _ACEOF
 
diff --git a/unix/configure.in b/unix/configure.in
index b2cf87a..aea5ee5 100644
--- a/unix/configure.in
+++ b/unix/configure.in
@@ -731,12 +731,16 @@ fi
 
 AC_CACHE_CHECK([whether the cpuid instruction is usable], tcl_cv_cpuid, [
     AC_TRY_LINK(, [
-	int index,ax,bx,cx,dx;
-	__asm__ __volatile__ ("cpuid":\
-	"=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (index));
+	int index,regsPtr[4];
+    __asm__ __volatile__("mov %%ebx, %%edi     \n\t"
+                 "cpuid            \n\t"
+                 "mov %%ebx, %%esi   \n\t"
+                 "mov %%edi, %%ebx  \n\t"
+                 : "=a"(regsPtr[0]), "=S"(regsPtr[1]), "=c"(regsPtr[2]), "=d"(regsPtr[3])
+                 : "a"(index));
     ], tcl_cv_cpuid=yes, tcl_cv_cpuid=no)])
 if test $tcl_cv_cpuid = yes; then
-    AC_DEFINE(HAVE_CPUID)
+    AC_DEFINE(HAVE_CPUID, 1, [Is the cpuid instruction usable?])
 fi
 
 #--------------------------------------------------------------------
diff --git a/unix/tclUnixCompat.c b/unix/tclUnixCompat.c
index 0626111..d9d5052 100644
--- a/unix/tclUnixCompat.c
+++ b/unix/tclUnixCompat.c
@@ -803,8 +803,7 @@ CopyString(
  *	Get CPU ID information on an Intel box under UNIX (either Linux or Cygwin)
  *
  * Results:
- *	Returns TCL_OK if successful, TCL_ERROR if CPUID is not supported or
- *	fails.
+ *	Returns TCL_OK if successful, TCL_ERROR if CPUID is not supported.
  *
  * Side effects:
  *	If successful, stores EAX, EBX, ECX and EDX registers after the CPUID
@@ -820,14 +819,14 @@ TclWinCPUID(
 {
     int status = TCL_ERROR;
 
-#if defined(HAVE_CPUID) && defined(__CYGWIN__)
-    __asm__ __volatile__("pushl %%ebx      \n\t" /* save %ebx */
+    /* See: <http://en.wikipedia.org/wiki/CPUID> */
+#if defined(HAVE_CPUID)
+    __asm__ __volatile__("mov %%ebx, %%edi     \n\t" /* save %ebx */
                  "cpuid            \n\t"
-                 "movl %%ebx, %1   \n\t" /* save what cpuid just put in %ebx */
-                 "popl %%ebx       \n\t" /* restore the old %ebx */
-                 : "=a"(regsPtr[0]), "=r"(regsPtr[1]), "=c"(regsPtr[2]), "=d"(regsPtr[3])
-                 : "a"(index)
-                 : "cc");
+                 "mov %%ebx, %%esi   \n\t" /* save what cpuid just put in %ebx */
+                 "mov %%edi, %%ebx  \n\t" /* restore the old %ebx */
+                 : "=a"(regsPtr[0]), "=S"(regsPtr[1]), "=c"(regsPtr[2]), "=d"(regsPtr[3])
+                 : "a"(index));
     status = TCL_OK;
 #endif
     return status;