[thirdparty/gcc.git] / gcc / config / i386 / cygwin.asm

/* stuff needed for libgcc on win32.
 *
 *   Copyright (C) 1996, 1998, 2001, 2003, 2008, 2009 Free Software Foundation, Inc.
 *   Written By Steve Chamberlain
 * 
 * This file is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 3, or (at your option) any
 * later version.
 * 
 * This file is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * Under Section 7 of GPL version 3, you are granted additional
 * permissions described in the GCC Runtime Library Exception, version
 * 3.1, as published by the Free Software Foundation.
 * 
 * You should have received a copy of the GNU General Public License and
 * a copy of the GCC Runtime Library Exception along with this program;
 * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

#ifdef L_chkstk

/* Function prologue calls _alloca to probe the stack when allocating more
   than CHECK_STACK_LIMIT bytes in one go.  Touching the stack at 4K
   increments is necessary to ensure that the guard pages used
   by the OS virtual memory manger are allocated in correct sequence.  */

	.global ___chkstk
	.global	__alloca
#ifndef _WIN64
___chkstk:
__alloca:
	pushl	%ecx		/* save temp */
	leal	8(%esp), %ecx	/* point past return addr */
	cmpl	$0x1000, %eax	/* > 4k ?*/
	jb	Ldone

Lprobe:
	subl	$0x1000, %ecx  		/* yes, move pointer down 4k*/
	orl	$0x0, (%ecx)   		/* probe there */
	subl	$0x1000, %eax  	 	/* decrement count */
	cmpl	$0x1000, %eax
	ja	Lprobe         	 	/* and do it again */

Ldone:
	subl	%eax, %ecx	   
	orl	$0x0, (%ecx)	/* less than 4k, just peek here */

	movl	%esp, %eax	/* save old stack pointer */
	movl	%ecx, %esp	/* decrement stack */
	movl	(%eax), %ecx	/* recover saved temp */
	movl	4(%eax), %eax	/* recover return address */

	/* Push the return value back.  Doing this instead of just
	   jumping to %eax preserves the cached call-return stack
	   used by most modern processors.  */
	pushl	%eax
	ret
#else
/* __alloca is a normal function call, which uses %rcx as the argument.  And stack space
   for the argument is saved.  */
__alloca:
 	movq	%rcx, %rax
	addq	$0x7, %rax
	andq	$0xfffffffffffffff8, %rax
	popq	%rcx		/* pop return address */
	popq	%r10		/* Pop the reserved stack space.  */
	movq	%rsp, %r10	/* get sp */
	cmpq	$0x1000, %rax	/* > 4k ?*/
	jb	Ldone_alloca

Lprobe_alloca:
	subq	$0x1000, %r10  		/* yes, move pointer down 4k*/
	orq	$0x0, (%r10)   		/* probe there */
	subq	$0x1000, %rax  	 	/* decrement count */
	cmpq	$0x1000, %rax
	ja	Lprobe_alloca         	 	/* and do it again */

Ldone_alloca:
	subq	%rax, %r10
	orq	$0x0, (%r10)	/* less than 4k, just peek here */
	movq	%r10, %rax
	subq	$0x8, %r10	/* Reserve argument stack space.  */
	movq	%r10, %rsp	/* decrement stack */

	/* Push the return value back.  Doing this instead of just
	   jumping to %rcx preserves the cached call-return stack
	   used by most modern processors.  */
	pushq	%rcx
	ret

/* ___chkstk is a *special* function call, which uses %rax as the argument.
   We avoid clobbering the 4 integer argument registers, %rcx, %rdx, 
   %r8 and %r9, which leaves us with %rax, %r10, and %r11 to use.  */
___chkstk:
	addq	$0x7, %rax	/* Make sure stack is on alignment of 8.  */
	andq	$0xfffffffffffffff8, %rax
	popq	%r11		/* pop return address */
	movq	%rsp, %r10	/* get sp */
	cmpq	$0x1000, %rax	/* > 4k ?*/
	jb	Ldone

Lprobe:
	subq	$0x1000, %r10  		/* yes, move pointer down 4k*/
	orl	$0x0, (%r10)   		/* probe there */
	subq	$0x1000, %rax  	 	/* decrement count */
	cmpq	$0x1000, %rax
	ja	Lprobe         	 	/* and do it again */

Ldone:
	subq	%rax, %r10
	orl	$0x0, (%r10)	/* less than 4k, just peek here */
	movq	%r10, %rsp	/* decrement stack */

	/* Push the return value back.  Doing this instead of just
	   jumping to %r11 preserves the cached call-return stack
	   used by most modern processors.  */
	pushq	%r11
	ret
#endif
#endif
Commit	Line	Data
f5c64a69 DS	1	/* stuff needed for libgcc on win32.
f5c64a69 DS	2	*
748086b7	3	* Copyright (C) 1996, 1998, 2001, 2003, 2008, 2009 Free Software Foundation, Inc.
f5c64a69 DS	4	* Written By Steve Chamberlain
	5	*
	6	* This file is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the
748086b7	8	* Free Software Foundation; either version 3, or (at your option) any
f5c64a69 DS	9	* later version.
f5c64a69 DS	10	*
f5c64a69 DS	11	* This file is distributed in the hope that it will be useful, but
	12	* WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* General Public License for more details.
	15	*
748086b7 JJ	16	* Under Section 7 of GPL version 3, you are granted additional
	17	* permissions described in the GCC Runtime Library Exception, version
	18	* 3.1, as published by the Free Software Foundation.
f5c64a69	19	*
748086b7 JJ	20	* You should have received a copy of the GNU General Public License and
	21	* a copy of the GCC Runtime Library Exception along with this program;
	22	* see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	23	* <http://www.gnu.org/licenses/>.
f5c64a69	24	*/
3a2c1cd8 MM	25
	26	#ifdef L_chkstk
	27
f5c64a69 DS	28	/* Function prologue calls _alloca to probe the stack when allocating more
	29	than CHECK_STACK_LIMIT bytes in one go. Touching the stack at 4K
	30	increments is necessary to ensure that the guard pages used
	31	by the OS virtual memory manger are allocated in correct sequence. */
	32
3a2c1cd8 MM	33	.global ___chkstk
3a2c1cd8 MM	34	.global __alloca
ccf8e764	35	#ifndef _WIN64
3a2c1cd8 MM	36	___chkstk:
3a2c1cd8 MM	37	__alloca:
ccf8e764 RH	38	pushl %ecx /* save temp */
	39	leal 8(%esp), %ecx /* point past return addr */
	40	cmpl $0x1000, %eax /* > 4k ?*/
	41	jb Ldone
3a2c1cd8	42
ccf8e764 RH	43	Lprobe:
	44	subl $0x1000, %ecx /* yes, move pointer down 4k*/
	45	orl $0x0, (%ecx) /* probe there */
	46	subl $0x1000, %eax /* decrement count */
	47	cmpl $0x1000, %eax
	48	ja Lprobe /* and do it again */
3a2c1cd8	49
ccf8e764 RH	50	Ldone:
	51	subl %eax, %ecx
	52	orl $0x0, (%ecx) /* less than 4k, just peek here */
3a2c1cd8	53
ccf8e764 RH	54	movl %esp, %eax /* save old stack pointer */
	55	movl %ecx, %esp /* decrement stack */
	56	movl (%eax), %ecx /* recover saved temp */
	57	movl 4(%eax), %eax /* recover return address */
3a2c1cd8	58
ccf8e764 RH	59	/* Push the return value back. Doing this instead of just
	60	jumping to %eax preserves the cached call-return stack
	61	used by most modern processors. */
	62	pushl %eax
	63	ret
	64	#else
35b35fd0 KT	65	/* __alloca is a normal function call, which uses %rcx as the argument. And stack space
35b35fd0 KT	66	for the argument is saved. */
ccf8e764	67	__alloca:
35b35fd0 KT	68	movq %rcx, %rax
	69	addq $0x7, %rax
	70	andq $0xfffffffffffffff8, %rax
	71	popq %rcx /* pop return address */
	72	popq %r10 /* Pop the reserved stack space. */
	73	movq %rsp, %r10 /* get sp */
	74	cmpq $0x1000, %rax /* > 4k ?*/
	75	jb Ldone_alloca
	76
	77	Lprobe_alloca:
	78	subq $0x1000, %r10 /* yes, move pointer down 4k*/
	79	orq $0x0, (%r10) /* probe there */
	80	subq $0x1000, %rax /* decrement count */
	81	cmpq $0x1000, %rax
	82	ja Lprobe_alloca /* and do it again */
	83
	84	Ldone_alloca:
	85	subq %rax, %r10
	86	orq $0x0, (%r10) /* less than 4k, just peek here */
	87	movq %r10, %rax
	88	subq $0x8, %r10 /* Reserve argument stack space. */
	89	movq %r10, %rsp /* decrement stack */
	90
	91	/* Push the return value back. Doing this instead of just
	92	jumping to %rcx preserves the cached call-return stack
	93	used by most modern processors. */
	94	pushq %rcx
	95	ret
ccf8e764 RH	96
	97	/* ___chkstk is a special function call, which uses %rax as the argument.
	98	We avoid clobbering the 4 integer argument registers, %rcx, %rdx,
	99	%r8 and %r9, which leaves us with %rax, %r10, and %r11 to use. */
	100	___chkstk:
35b35fd0 KT	101	addq $0x7, %rax /* Make sure stack is on alignment of 8. */
35b35fd0 KT	102	andq $0xfffffffffffffff8, %rax
ccf8e764 RH	103	popq %r11 /* pop return address */
	104	movq %rsp, %r10 /* get sp */
	105	cmpq $0x1000, %rax /* > 4k ?*/
	106	jb Ldone
3a2c1cd8	107
ccf8e764 RH	108	Lprobe:
	109	subq $0x1000, %r10 /* yes, move pointer down 4k*/
	110	orl $0x0, (%r10) /* probe there */
	111	subq $0x1000, %rax /* decrement count */
	112	cmpq $0x1000, %rax
	113	ja Lprobe /* and do it again */
	114
	115	Ldone:
	116	subq %rax, %r10
	117	orl $0x0, (%r10) /* less than 4k, just peek here */
	118	movq %r10, %rsp /* decrement stack */
	119
	120	/* Push the return value back. Doing this instead of just
	121	jumping to %r11 preserves the cached call-return stack
	122	used by most modern processors. */
	123	pushq %r11
	124	ret
	125	#endif
3a2c1cd8	126	#endif