[apple/xnu.git] / osfmk / i386 / rtclock_asm_native.h

/*
 * Copyright (c) 2010 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@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * @APPLE_FREE_COPYRIGHT@
 */
/*
 *	File:		rtclock_asm_native.h
 *	Purpose:	Native routines for reading nanotime
 */

#ifndef _PAL_RTCLOCK_ASM_NATIVE_H_
#define _PAL_RTCLOCK_ASM_NATIVE_H_


#if defined(__i386__)
/*
 * Assembly snippet included in exception handlers and rtc_nanotime_read()
 * %edi points to nanotime info struct
 * %edx:%eax returns nanotime
 */
#define PAL_RTC_NANOTIME_READ_FAST()					  \
0:	movl	RNT_GENERATION(%edi),%esi	/* being updated? */	; \
	testl	%esi,%esi						; \
	jz	0b				/* wait until done */	; \
	lfence								; \
	rdtsc								; \
	lfence								; \
	subl	RNT_TSC_BASE(%edi),%eax					; \
	sbbl	RNT_TSC_BASE+4(%edi),%edx	/* tsc - tsc_base */	; \
	movl	RNT_SCALE(%edi),%ecx		/* * scale factor */	; \
	movl	%edx,%ebx						; \
	mull	%ecx							; \
	movl	%ebx,%eax						; \
	movl	%edx,%ebx						; \
	mull	%ecx							; \
	addl	%ebx,%eax						; \
	adcl	$0,%edx							; \
	addl	RNT_NS_BASE(%edi),%eax		/* + ns_base */		; \
	adcl	RNT_NS_BASE+4(%edi),%edx				; \
	cmpl	RNT_GENERATION(%edi),%esi	/* check for update */	; \
	jne	0b				/* do it all again */

#elif defined(__x86_64__)

/*
 * Assembly snippet included in exception handlers and rtc_nanotime_read()
 * %rdi points to nanotime info struct.
 * %rax returns nanotime
 */
#define PAL_RTC_NANOTIME_READ_FAST()					  \
0:	movl	RNT_GENERATION(%rdi),%esi				; \
	test        %esi,%esi		/* info updating? */		; \
        jz        0b			/* - wait if so */		; \
	lfence								; \
	rdtsc								; \
	lfence								; \
	shlq	$32,%rdx						; \
	orq	%rdx,%rax			/* %rax := tsc */	; \
	subq	RNT_TSC_BASE(%rdi),%rax		/* tsc - tsc_base */	; \
	xorq	%rcx,%rcx						; \
	movl	RNT_SCALE(%rdi),%ecx					; \
	mulq	%rcx				/* delta * scale */	; \
	shrdq	$32,%rdx,%rax			/* %rdx:%rax >>= 32 */	; \
	addq	RNT_NS_BASE(%rdi),%rax		/* add ns_base */	; \
	cmpl	RNT_GENERATION(%rdi),%esi	/* repeat if changed */ ; \
	jne	0b

#endif /* !defined(x86_64) */


#endif /* _PAL_RTCLOCK_ASM_NATIVE_H_ */
Commit	Line	Data
6601e61a	1	/*
6d2010ae	2	* Copyright (c) 2010 Apple Inc. All rights reserved.
6601e61a	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
6601e61a	5	*
2d21ac55 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.
6601e61a	14	*
2d21ac55 A	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
6601e61a A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
6601e61a A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	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.
6601e61a	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
6601e61a A	27	*/
	28	/*
	29	* @OSF_COPYRIGHT@
	30	*/
0c530ab8 A	31	/*
	32	* @APPLE_FREE_COPYRIGHT@
	33	*/
	34	/*
6d2010ae A	35	* File: rtclock_asm_native.h
6d2010ae A	36	* Purpose: Native routines for reading nanotime
0c530ab8 A	37	*/
0c530ab8 A	38
6d2010ae A	39	#ifndef _PAL_RTCLOCK_ASM_NATIVE_H_
6d2010ae A	40	#define _PAL_RTCLOCK_ASM_NATIVE_H_
0c530ab8	41
593a1d5f A	42
	43	#if defined(__i386__)
	44	/*
	45	* Assembly snippet included in exception handlers and rtc_nanotime_read()
	46	* %edi points to nanotime info struct
	47	* %edx:%eax returns nanotime
	48	*/
6d2010ae	49	#define PAL_RTC_NANOTIME_READ_FAST() \
593a1d5f A	50	0: movl RNT_GENERATION(%edi),%esi /* being updated? */ ; \
	51	testl %esi,%esi ; \
	52	jz 0b /* wait until done */ ; \
c910b4d9	53	lfence ; \
593a1d5f A	54	rdtsc ; \
	55	lfence ; \
	56	subl RNT_TSC_BASE(%edi),%eax ; \
	57	sbbl RNT_TSC_BASE+4(%edi),%edx /* tsc - tsc_base */ ; \
	58	movl RNT_SCALE(%edi),%ecx /* * scale factor */ ; \
	59	movl %edx,%ebx ; \
	60	mull %ecx ; \
	61	movl %ebx,%eax ; \
	62	movl %edx,%ebx ; \
	63	mull %ecx ; \
	64	addl %ebx,%eax ; \
	65	adcl $0,%edx ; \
	66	addl RNT_NS_BASE(%edi),%eax /* + ns_base */ ; \
	67	adcl RNT_NS_BASE+4(%edi),%edx ; \
	68	cmpl RNT_GENERATION(%edi),%esi /* check for update */ ; \
	69	jne 0b /* do it all again */
	70
	71	#elif defined(__x86_64__)
	72
	73	/*
	74	* Assembly snippet included in exception handlers and rtc_nanotime_read()
	75	* %rdi points to nanotime info struct.
	76	* %rax returns nanotime
	77	*/
6d2010ae	78	#define PAL_RTC_NANOTIME_READ_FAST() \
593a1d5f	79	0: movl RNT_GENERATION(%rdi),%esi ; \
6d2010ae A	80	test %esi,%esi /* info updating? */ ; \
6d2010ae A	81	jz 0b /* - wait if so */ ; \
c910b4d9	82	lfence ; \
593a1d5f A	83	rdtsc ; \
	84	lfence ; \
	85	shlq $32,%rdx ; \
	86	orq %rdx,%rax /* %rax := tsc */ ; \
	87	subq RNT_TSC_BASE(%rdi),%rax /* tsc - tsc_base */ ; \
	88	xorq %rcx,%rcx ; \
	89	movl RNT_SCALE(%rdi),%ecx ; \
	90	mulq %rcx /* delta * scale */ ; \
	91	shrdq $32,%rdx,%rax /* %rdx:%rax >>= 32 */ ; \
	92	addq RNT_NS_BASE(%rdi),%rax /* add ns_base */ ; \
	93	cmpl RNT_GENERATION(%rdi),%esi /* repeat if changed */ ; \
	94	jne 0b
	95
6d2010ae A	96	#endif /* !defined(x86_64) */
6d2010ae A	97
593a1d5f	98
6d2010ae	99	#endif /* _PAL_RTCLOCK_ASM_NATIVE_H_ */