From 143422fa0a7735c72c8ddd25ec0197c8ea305df5 Mon Sep 17 00:00:00 2001
From: Ben Gras <ben@minix3.org>
Date: Thu, 14 May 2009 15:55:28 +0000
Subject: [PATCH] C CPUID interface.

---
 lib/i386/misc/Makefile.in |  1 +
 lib/i386/misc/_cpuid.s    | 44 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100755 lib/i386/misc/_cpuid.s

diff --git a/lib/i386/misc/Makefile.in b/lib/i386/misc/Makefile.in
index 511524f08..3b139e97e 100644
--- a/lib/i386/misc/Makefile.in
+++ b/lib/i386/misc/Makefile.in
@@ -5,6 +5,7 @@ CFLAGS="-O -D_MINIX -D_POSIX_SOURCE"
 LIBRARIES=libc
 
 libc_FILES=" \
+	_cpuid.s \
 	alloca.s \
 	get_bp.s \
 	getprocessor.s \
diff --git a/lib/i386/misc/_cpuid.s b/lib/i386/misc/_cpuid.s
new file mode 100755
index 000000000..6ca569a30
--- /dev/null
+++ b/lib/i386/misc/_cpuid.s
@@ -0,0 +1,44 @@
+! _cpuid() - interface to cpuid instruction
+
+.sect .text; .sect .rom; .sect .data; .sect .bss
+.sect .text
+
+! int _cpuid(u32_t eax, u32_t *eax, u32_t *ebx, u32_t *ecx, u32_t *edx);
+! 0 for OK, nonzero for unsupported
+
+.define	__cpuid
+
+__cpuid:
+	push	ebp
+
+	mov	ebp, esp
+
+	! save work registers
+	push	eax
+	push	ebx
+	push	ecx
+	push	edx
+
+	! set eax parameter to cpuid and execute cpuid
+	mov	eax,  24(esp)
+	.data1	0x0F, 0xA2	! CPUID
+
+	! store results in pointer arguments
+	mov	ebp, 28(esp)
+	mov	(ebp), eax
+	mov	ebp, 32(esp)
+	mov	(ebp), ebx
+	mov	ebp, 36(esp)
+	mov	(ebp), ecx
+	mov	ebp, 40(esp)
+	mov	(ebp), edx
+
+	! restore registers
+	pop	edx
+	pop	ecx
+	pop	ebx
+	pop	eax
+
+	pop	ebp
+
+	ret