[apple/xnu.git] / osfmk / i386 / commpage / commpage_gettimeofday.s

/*
 * Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include <sys/appleapiopts.h>
#include <machine/cpu_capabilities.h>
#include <machine/commpage.h>

#define NSEC_PER_SEC	1000*1000*1000
#define NSEC_PER_USEC	1000

        .text
        .align  2, 0x90

Lgettimeofday:
	push	%ebp
	mov	%esp,%ebp
	push	%esi
	push	%edi
	push	%ebx

0:
	cmp	$0,_COMM_PAGE_TIMEENABLE
	je	4f
	mov	_COMM_PAGE_TIMEBASE,%esi
	mov	_COMM_PAGE_TIMEBASE+4,%edi
	mov	_COMM_PAGE_TIMESTAMP,%ebx

	mov	$ _COMM_PAGE_NANOTIME,%eax
	call	*%eax		/* get ns in %edx:%eax */

	cmp	_COMM_PAGE_TIMEBASE,%esi
	jne	0b
	cmp	_COMM_PAGE_TIMEBASE+4,%edi
	jne	0b
	cmp	$0,_COMM_PAGE_TIMEENABLE
	je	4f
	
	mov	$ NSEC_PER_SEC,%ecx
	sub	%esi,%eax
	sbb	%edi,%edx
	div	%ecx
	add	%eax,%ebx

	mov	$ NSEC_PER_USEC,%ecx
	mov	%edx,%eax
	xor	%edx,%edx
	div	%ecx

	mov	8(%ebp),%ecx
	mov	%ebx,(%ecx)
	mov	%eax,4(%ecx)
	xor	%eax,%eax

3:
	pop	%ebx
	pop	%edi
	pop	%esi
	pop	%ebp
	ret
4:				/* fail */
	movl	$1,%eax
	jmp	3b

	COMMPAGE_DESCRIPTOR(gettimeofday,_COMM_PAGE_GETTIMEOFDAY,0,0)


	.code64
        .text
        .align  2, 0x90

Lgettimeofday_64:			// %rdi = ptr to timeval
	pushq	%rbp			// set up a frame for backtraces
	movq	%rsp,%rbp
	movq	%rdi,%r9		// save ptr to timeval
	movq	$_COMM_PAGE_32_TO_64(_COMM_PAGE_TIMEBASE),%r10
0:
	cmpl	$0,_TIMEENABLE(%r10)	// is data valid? (test _COMM_PAGE_TIMEENABLE)
	jz	4f			// no
	movq	_TIMEBASE(%r10),%r11	// get _COMM_PAGE_TIMEBASE
	movq	$_COMM_PAGE_32_TO_64(_COMM_PAGE_NANOTIME),%rax
	call	*%rax			// get %rax <- nanotime(), preserving %r9, %r10 and %r11
	movl	_TIMESTAMP(%r10),%r8d	// get _COMM_PAGE_TIMESTAMP
	cmpq	_TIMEBASE(%r10),%r11	// has _COMM_PAGE_TIMEBASE changed?
	jne	0b			// loop until we have consistent data
	cmpl	$0,_TIMEENABLE(%r10)	// is data valid? (test _COMM_PAGE_TIMEENABLE)
	jz	4f			// no
	
	movl	$ NSEC_PER_SEC,%ecx
	subq	%r11,%rax		// generate nanoseconds since timestamp
	movq	%rax,%rdx
	shrq	$32,%rdx		// get high half of delta in %edx
	divl	%ecx			// %eax <- seconds since timestamp, %edx <- nanoseconds
	addl	%eax,%r8d		// add seconds elapsed to timestamp seconds

	movl	$ NSEC_PER_USEC,%ecx
	movl	%edx,%eax
	xorl	%edx,%edx
	divl	%ecx			// divide residual ns by 1000 to get residual us in %eax
	
	movq	%r8,(%r9)		// store 64-bit seconds into timeval
	movl	%eax,8(%r9)		// store 32-bit useconds into timeval
	xorl	%eax,%eax		// return 0 for success
3:
	popq	%rbp
	ret
4:					// fail
	movl	$1,%eax
	jmp	3b

	COMMPAGE_DESCRIPTOR(gettimeofday_64,_COMM_PAGE_GETTIMEOFDAY,0,0)
Commit	Line	Data
1c79356b	1	/*
89b3af67	2	* Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
8f6c56a5	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
8f6c56a5 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
8ad349bb	24	* limitations under the License.
8f6c56a5 A	25	*
8f6c56a5 A	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b	27	*/
55e303ae A	28
	29	#include <sys/appleapiopts.h>
	30	#include <machine/cpu_capabilities.h>
	31	#include <machine/commpage.h>
	32
89b3af67 A	33	#define NSEC_PER_SEC 100010001000
	34	#define NSEC_PER_USEC 1000
	35
55e303ae A	36	.text
	37	.align 2, 0x90
	38
	39	Lgettimeofday:
89b3af67 A	40	push %ebp
	41	mov %esp,%ebp
	42	push %esi
	43	push %edi
	44	push %ebx
	45
	46	0:
	47	cmp $0,_COMM_PAGE_TIMEENABLE
	48	je 4f
	49	mov _COMM_PAGE_TIMEBASE,%esi
	50	mov _COMM_PAGE_TIMEBASE+4,%edi
	51	mov _COMM_PAGE_TIMESTAMP,%ebx
	52
	53	mov $ _COMM_PAGE_NANOTIME,%eax
	54	call %eax / get ns in %edx:%eax */
	55
	56	cmp _COMM_PAGE_TIMEBASE,%esi
	57	jne 0b
	58	cmp _COMM_PAGE_TIMEBASE+4,%edi
	59	jne 0b
	60	cmp $0,_COMM_PAGE_TIMEENABLE
	61	je 4f
	62
	63	mov $ NSEC_PER_SEC,%ecx
	64	sub %esi,%eax
	65	sbb %edi,%edx
	66	div %ecx
	67	add %eax,%ebx
	68
	69	mov $ NSEC_PER_USEC,%ecx
	70	mov %edx,%eax
	71	xor %edx,%edx
	72	div %ecx
	73
	74	mov 8(%ebp),%ecx
	75	mov %ebx,(%ecx)
	76	mov %eax,4(%ecx)
	77	xor %eax,%eax
	78
	79	3:
	80	pop %ebx
	81	pop %edi
	82	pop %esi
	83	pop %ebp
55e303ae	84	ret
89b3af67 A	85	4: /* fail */
	86	movl $1,%eax
	87	jmp 3b
55e303ae A	88
55e303ae A	89	COMMPAGE_DESCRIPTOR(gettimeofday,_COMM_PAGE_GETTIMEOFDAY,0,0)
89b3af67 A	90
	91
	92	.code64
	93	.text
	94	.align 2, 0x90
	95
	96	Lgettimeofday_64: // %rdi = ptr to timeval
	97	pushq %rbp // set up a frame for backtraces
	98	movq %rsp,%rbp
	99	movq %rdi,%r9 // save ptr to timeval
	100	movq $_COMM_PAGE_32_TO_64(_COMM_PAGE_TIMEBASE),%r10
	101	0:
	102	cmpl $0,_TIMEENABLE(%r10) // is data valid? (test _COMM_PAGE_TIMEENABLE)
	103	jz 4f // no
	104	movq _TIMEBASE(%r10),%r11 // get _COMM_PAGE_TIMEBASE
	105	movq $_COMM_PAGE_32_TO_64(_COMM_PAGE_NANOTIME),%rax
	106	call *%rax // get %rax <- nanotime(), preserving %r9, %r10 and %r11
	107	movl _TIMESTAMP(%r10),%r8d // get _COMM_PAGE_TIMESTAMP
	108	cmpq _TIMEBASE(%r10),%r11 // has _COMM_PAGE_TIMEBASE changed?
	109	jne 0b // loop until we have consistent data
	110	cmpl $0,_TIMEENABLE(%r10) // is data valid? (test _COMM_PAGE_TIMEENABLE)
	111	jz 4f // no
	112
	113	movl $ NSEC_PER_SEC,%ecx
	114	subq %r11,%rax // generate nanoseconds since timestamp
	115	movq %rax,%rdx
	116	shrq $32,%rdx // get high half of delta in %edx
	117	divl %ecx // %eax <- seconds since timestamp, %edx <- nanoseconds
	118	addl %eax,%r8d // add seconds elapsed to timestamp seconds
	119
	120	movl $ NSEC_PER_USEC,%ecx
	121	movl %edx,%eax
	122	xorl %edx,%edx
	123	divl %ecx // divide residual ns by 1000 to get residual us in %eax
	124
	125	movq %r8,(%r9) // store 64-bit seconds into timeval
	126	movl %eax,8(%r9) // store 32-bit useconds into timeval
	127	xorl %eax,%eax // return 0 for success
	128	3:
	129	popq %rbp
	130	ret
	131	4: // fail
	132	movl $1,%eax
	133	jmp 3b
	134
	135	COMMPAGE_DESCRIPTOR(gettimeofday_64,_COMM_PAGE_GETTIMEOFDAY,0,0)