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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.
This commit is contained in:
drochner 2012-08-31 20:57:24 +00:00
parent 72b7fc9f19
commit 0e9330ed96
1 changed files with 4 additions and 4 deletions
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8
lib/libc/arch/i386/gen/_lwp.c
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@ -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 (*start)(void *),
/* 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;