From 977f9ab515e707449e044bf6c3f71b4cd82f449d Mon Sep 17 00:00:00 2001
From: Jeff Roberson <jeff@FreeBSD.org>
Date: Wed, 1 Oct 2003 05:25:27 +0000
Subject: [PATCH]  - Add ss2_pagezero() for zeroing pages using the movnti
 instruction.  This    instruction is enabled with SSE2 but does not use SSE
 registers.  It is a    "non-temporal" move which bypasses the cache and does
 not dirty lines.

---
 sys/i386/i386/support.s   | 14 ++++++++++++++
 sys/i386/include/md_var.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/sys/i386/i386/support.s b/sys/i386/i386/support.s
index 6af498019e5d..b03f1dc2e828 100644
--- a/sys/i386/i386/support.s
+++ b/sys/i386/i386/support.s
@@ -350,6 +350,20 @@ intreg_i586_bzero:
 	ret
 #endif /* I586_CPU && defined(DEV_NPX) */
 
+ENTRY(sse2_pagezero)
+	pushl	%ebx
+	movl	8(%esp),%ecx
+	movl	%ecx,%eax
+	addl	$4096,%eax
+	xor	%ebx,%ebx
+1:
+	movnti	%ebx,(%ecx)
+	addl	$4,%ecx
+	cmpl	%ecx,%eax
+	jne	1b
+	popl	%ebx
+	ret
+
 ENTRY(i686_pagezero)
 	pushl	%edi
 	pushl	%ebx
diff --git a/sys/i386/include/md_var.h b/sys/i386/include/md_var.h
index 4fe29d3ad352..526c39017879 100644
--- a/sys/i386/include/md_var.h
+++ b/sys/i386/include/md_var.h
@@ -93,6 +93,7 @@ void	i586_bzero(void *buf, size_t len);
 int	i586_copyin(const void *udaddr, void *kaddr, size_t len);
 int	i586_copyout(const void *kaddr, void *udaddr, size_t len);
 void	i686_pagezero(void *addr);
+void	sse2_pagezero(void *addr);
 void	init_AMD_Elan_sc520(void);
 int	is_physical_memory(vm_offset_t addr);
 vm_paddr_t kvtop(void *addr);