The Quake sources as originally release under the GPL license on December 21, 1999

WinQuake/dosasm.s

@@ -0,0 +1,77 @@
+#include "asm_i386.h"
+
+.data
+fpenv:	.long	0, 0, 0, 0, 0, 0, 0, 0
+
+.text
+.globl	C(StartMSRInterval)
+C(StartMSRInterval):
+	movl	$0x11,%ecx	// read the CESR
+	.byte	0x0F
+	.byte	0x32		// RDMSR
+
+	andl	$0xFE3FFE3F,%eax	// stop both counters
+	.byte	0x0F
+	.byte	0x30		// WRMSR
+
+	movl	4(%esp),%eax	// point counter 0 to desired event, with counters
+	andl	$0x3F,%eax		//  still stopped
+	movl	$0x11,%ecx
+	.byte	0x0F
+	.byte	0x30		// WRMSR
+
+	movl	$0x12,%ecx	// set counter 0 to the value 0
+	subl	%eax,%eax
+	subl	%edx,%edx
+	.byte	0x0F
+	.byte	0x30		// WRMSR
+	
+	movl	4(%esp),%eax // restart counter 0 with selected event
+	andl	$0x3F,%eax
+	subl	%edx,%edx
+	orl		$0xC0,%eax
+	movl	$0x11,%ecx	// control and event select
+	.byte	0x0F
+	.byte	0x30		// WRMSR
+
+	ret
+
+.globl	C(EndMSRInterval)
+C(EndMSRInterval):
+	movl	$0x12,%ecx	// counter 0
+	.byte	0x0F
+	.byte	0x32		// RDMSR
+
+	ret					// lower 32 bits of count in %eax
+
+#if 0
+	.data
+Lxxx:	.long	0
+
+	.text
+
+.globl C(setstackcheck)
+C(setstackcheck):
+
+	movl	%esp,%eax
+	subl	$0x38000,%eax
+	movl	$0x5A5A5A5A,(%eax)
+	movl	%eax,Lxxx
+
+	ret
+
+
+.globl C(dostackcheck)
+C(dostackcheck):
+
+	movl	Lxxx,%edx
+	movl	$0,%eax
+
+	cmpl	$0x5A5A5A5A,(%edx)
+	jz		qqq
+	incl	%eax
+qqq:
+
+	ret
+#endif
+