C CPUID interface.

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 \

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