From b528b987da6f980d7705141667972b3623f620a4 Mon Sep 17 00:00:00 2001
From: Randy Heit <rheit@zdoom.fake>
Date: Fri, 4 Sep 2009 23:14:29 +0000
Subject: [PATCH] - Add an alternate PIC-compliant __cpuid macro in x86.cpp.

SVN r1793 (trunk)
---
 docs/rh-log.txt |  1 +
 src/x86.cpp     | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 128520ac38..465ad7a728 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -2,6 +2,7 @@ September 5, 2009  (Changes by Graf Zahl)
 - made menu dimming a mapping option but kept the CVARS as user override.
 
 September 4, 2009
+- Add an alternate PIC-compliant __cpuid macro in x86.cpp.
 - Fixed: S_LoadSound() did not byte-swap the frequency and length it reads
   from DMX sounds.
 - Fixed: PNGTexture must not use the FArchive >> operator as a short hand
diff --git a/src/x86.cpp b/src/x86.cpp
index 6fcfb55208..880149bc4e 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -25,10 +25,21 @@ void DumpCPUInfo(const CPUInfo *cpu)
 #include <mmintrin.h>
 #include <emmintrin.h>
 
+
 #ifdef __GNUC__
+#if defined(__i386__) && defined(__PIC__)
+// %ebx may by the PIC register. */
+#define __cpuid(output, func) \
+	__asm__ __volatile__("xchgl\t%%ebx, %1\n\t" \
+						 "cpuid\n\t" \
+						 "xchgl\t%%ebx, %1\n\t" \
+		: "=a" ((output)[0]), "=r" ((output)[1]), "=c" ((output)[2]), "=d" ((output)[3]) \
+		: "a" (func));
+#else
 #define __cpuid(output, func) __asm__ __volatile__("cpuid" : "=a" ((output)[0]),\
 	"=b" ((output)[1]), "=c" ((output)[2]), "=d" ((output)[3]) : "a" (func));
 #endif
+#endif
 
 void CheckCPUID(CPUInfo *cpu)
 {