[apple/xnu.git] / libsyscall / wrappers / __commpage_gettimeofday.s

/*
 * Copyright (c) 2003-2007 Apple 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>

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

#if defined(__i386__)

	.align	4
	.globl ___commpage_gettimeofday
___commpage_gettimeofday:
	push	%ebp
	mov	%esp,%ebp
	push	%esi
	push	%ebx
0:
	movl	_COMM_PAGE_GTOD_GENERATION,%esi	/* get generation (0 if disabled) */
	testl	%esi,%esi			/* disabled? */
	jz	4f

	call	_mach_absolute_time		/* get nanotime in %edx:%eax */
	
	sub	_COMM_PAGE_GTOD_NS_BASE,%eax
	sbb	_COMM_PAGE_GTOD_NS_BASE+4,%edx
	mov	_COMM_PAGE_GTOD_SEC_BASE,%ebx	/* load all the data before checking generation */
	mov	$ NSEC_PER_SEC,%ecx
	
	cmpl	_COMM_PAGE_GTOD_GENERATION,%esi	/* has time data changed out from under us? */
	jne	0b
	
	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	%esi
	pop	%ebp
	ret
4:				/* fail */
	movl	$1,%eax
	jmp	3b

#elif defined(__x86_64__)

	.align 4, 0x90
	.globl ___commpage_gettimeofday
___commpage_gettimeofday:
// %rdi = ptr to timeval
	pushq	%rbp			// set up a frame for backtraces
	pushq	%r12			// push callee-saved registers we want to use
	pushq	%r13
	pushq	%r14
	subq	$8, %rsp
	movq	%rsp,%rbp
	movq	%rdi,%r12		// save ptr to timeval
	movq	$(_COMM_PAGE_TIME_DATA_START),%r13
0:
	movl	_GTOD_GENERATION(%r13),%r14d	// get generation (0 if disabled)
	testl	%r14d,%r14d		// disabled?
	jz	4f

	call	_mach_absolute_time	// get %rax <- nanotime()
	
	movl	_GTOD_SEC_BASE(%r13),%r8d	// get _COMM_PAGE_TIMESTAMP
	subq	_GTOD_NS_BASE(%r13),%rax	// generate nanoseconds since timestamp
	cmpl	_GTOD_GENERATION(%r13),%r14d	// has data changed out from under us?
	jne	0b
	
	movl	$ NSEC_PER_SEC,%ecx
	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,(%r12)		// store 64-bit seconds into timeval
	movl	%eax,8(%r12)		// store 32-bit useconds into timeval
	xorl	%eax,%eax		// return 0 for success
3:
	addq	$8, %rsp
	popq	%r14
	popq	%r13
	popq	%r12
	popq	%rbp
	ret
4:					// fail
	movl	$1,%eax
	jmp	3b

#endif
Commit	Line	Data
39236c6e A	1	/*
	2	* Copyright (c) 2003-2007 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	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
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include <sys/appleapiopts.h>
	30	#include <machine/cpu_capabilities.h>
	31
	32	#define NSEC_PER_SEC 100010001000
	33	#define NSEC_PER_USEC 1000
	34
	35	#if defined(__i386__)
	36
	37	.align 4
	38	.globl ___commpage_gettimeofday
	39	___commpage_gettimeofday:
	40	push %ebp
	41	mov %esp,%ebp
	42	push %esi
	43	push %ebx
	44	0:
	45	movl _COMM_PAGE_GTOD_GENERATION,%esi /* get generation (0 if disabled) */
	46	testl %esi,%esi /* disabled? */
	47	jz 4f
	48
	49	call _mach_absolute_time /* get nanotime in %edx:%eax */
	50
	51	sub _COMM_PAGE_GTOD_NS_BASE,%eax
	52	sbb _COMM_PAGE_GTOD_NS_BASE+4,%edx
	53	mov _COMM_PAGE_GTOD_SEC_BASE,%ebx /* load all the data before checking generation */
	54	mov $ NSEC_PER_SEC,%ecx
	55
	56	cmpl _COMM_PAGE_GTOD_GENERATION,%esi /* has time data changed out from under us? */
	57	jne 0b
	58
	59	div %ecx
	60	add %eax,%ebx
	61
	62	mov $ NSEC_PER_USEC,%ecx
	63	mov %edx,%eax
	64	xor %edx,%edx
65	div %ecx
66
67	mov 8(%ebp),%ecx
68	mov %ebx,(%ecx)
69	mov %eax,4(%ecx)
70	xor %eax,%eax
71	3:
72	pop %ebx
73	pop %esi
74	pop %ebp
75	ret
76	4: /* fail */
77	movl $1,%eax
78	jmp 3b
79
80	#elif defined(__x86_64__)
81
82	.align 4, 0x90
83	.globl ___commpage_gettimeofday
84	___commpage_gettimeofday:
85	// %rdi = ptr to timeval
86	pushq %rbp // set up a frame for backtraces
87	pushq %r12 // push callee-saved registers we want to use
88	pushq %r13
89	pushq %r14
90	subq $8, %rsp
91	movq %rsp,%rbp
92	movq %rdi,%r12 // save ptr to timeval
93	movq $(_COMM_PAGE_TIME_DATA_START),%r13
94	0:
95	movl _GTOD_GENERATION(%r13),%r14d // get generation (0 if disabled)
96	testl %r14d,%r14d // disabled?
97	jz 4f
98
99	call _mach_absolute_time // get %rax <- nanotime()
100
101	movl _GTOD_SEC_BASE(%r13),%r8d // get _COMM_PAGE_TIMESTAMP
102	subq _GTOD_NS_BASE(%r13),%rax // generate nanoseconds since timestamp
103	cmpl _GTOD_GENERATION(%r13),%r14d // has data changed out from under us?
104	jne 0b
105
106	movl $ NSEC_PER_SEC,%ecx
107	movq %rax,%rdx
108	shrq $32,%rdx // get high half of delta in %edx
109	divl %ecx // %eax <- seconds since timestamp, %edx <- nanoseconds
110	addl %eax,%r8d // add seconds elapsed to timestamp seconds
111
112	movl $ NSEC_PER_USEC,%ecx
113	movl %edx,%eax
114	xorl %edx,%edx
115	divl %ecx // divide residual ns by 1000 to get residual us in %eax
116
117	movq %r8,(%r12) // store 64-bit seconds into timeval
118	movl %eax,8(%r12) // store 32-bit useconds into timeval
119	xorl %eax,%eax // return 0 for success
120	3:
121	addq $8, %rsp
122	popq %r14
123	popq %r13
124	popq %r12
125	popq %rbp
126	ret
127	4: // fail
128	movl $1,%eax
129	jmp 3b
130
131	#endif