Module Name: src
Committed By: drochner
Date: Fri Aug 31 20:57:24 UTC 2012
Modified Files:
src/lib/libc/arch/i386/gen: _lwp.c
Log Message:
Align the stack to a 16-byte boundary on LWP creation.
This is more than required by the ABI, but it makes programs using SSE
in a thread work without extra compiler flags or performance hit.
To generate a diff of this commit:
cvs rdiff -u -r1.7 -r1.8 src/lib/libc/arch/i386/gen/_lwp.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/arch/i386/gen/_lwp.c
diff -u src/lib/libc/arch/i386/gen/_lwp.c:1.7 src/lib/libc/arch/i386/gen/_lwp.c:1.8
--- src/lib/libc/arch/i386/gen/_lwp.c:1.7 Thu Feb 24 04:28:42 2011
+++ src/lib/libc/arch/i386/gen/_lwp.c Fri Aug 31 20:57:24 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: _lwp.c,v 1.7 2011/02/24 04:28:42 joerg Exp $ */
+/* $NetBSD: _lwp.c,v 1.8 2012/08/31 20:57:24 drochner Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: _lwp.c,v 1.7 2011/02/24 04:28:42 joerg Exp $");
+__RCSID("$NetBSD: _lwp.c,v 1.8 2012/08/31 20:57:24 drochner Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
@@ -56,9 +56,9 @@ _lwp_makecontext(ucontext_t *u, void (*s
/* LINTED uintptr_t is safe */
u->uc_mcontext.__gregs[_REG_EIP] = (uintptr_t)start;
- /* Align to a word */
+ /* Align to a 16-byte boundary for SSE */
/* LINTED uintptr_t is safe */
- sp = (void **) ((uintptr_t)(stack_base + stack_size) & ~0x3);
+ sp = (void **) (((uintptr_t)(stack_base + stack_size - 4) & ~0xf) + 4);
*--sp = arg;
*--sp = (void *) _lwp_exit;
