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

/*
 * Copyright (c) 2004-2007 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@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * @APPLE_FREE_COPYRIGHT@
 */
/*
 *	File:		rtclock.h
 *	Purpose:	Routines for handling the machine dependent
 *				real-time clock.
 */

#ifndef _I386_RTCLOCK_H_
#define _I386_RTCLOCK_H_

#ifndef ASSEMBLER
typedef struct rtc_nanotime {
	uint64_t	tsc_base;		/* timestamp */
	uint64_t	ns_base;		/* nanoseconds */
	uint32_t	scale;			/* tsc -> nanosec multiplier */
	uint32_t	shift;			/* tsc -> nanosec shift/div */
						/* shift is overloaded with
						 * lower 32bits of tsc_freq
						 * on slower machines (SLOW_TSC_THRESHOLD) */
	uint32_t	generation;		/* 0 == being updated */
	uint32_t	spare1;
} rtc_nanotime_t;

#include <kern/etimer.h>

struct cpu_data;

extern void	_rtc_nanotime_store(
			uint64_t	tsc,
			uint64_t	nsec,
			uint32_t	scale,
			uint32_t	shift,
			rtc_nanotime_t	*dst);

extern uint64_t	_rtc_nanotime_read(
			rtc_nanotime_t	*rntp,
			int		slow);

extern rtc_nanotime_t	rtc_nanotime_info;
#endif

#define	SLOW_TSC_THRESHOLD	1000067800	/* TSC is too slow for regular nanotime() algorithm */

#if defined(__i386__)
/*
 * Assembly snippet included in exception handlers and rtc_nanotime_read()
 * %edi points to nanotime info struct
 * %edx:%eax returns nanotime
 */
#define 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 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

#endif /* _I386_RTCLOCK_H_ */
Commit	Line	Data
6601e61a	1	/*
2d21ac55	2	* Copyright (c) 2004-2007 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	/*
	35	* File: rtclock.h
	36	* Purpose: Routines for handling the machine dependent
	37	* real-time clock.
	38	*/
	39
	40	#ifndef _I386_RTCLOCK_H_
	41	#define _I386_RTCLOCK_H_
	42
593a1d5f A	43	#ifndef ASSEMBLER
	44	typedef struct rtc_nanotime {
	45	uint64_t tsc_base; /* timestamp */
	46	uint64_t ns_base; /* nanoseconds */
	47	uint32_t scale; /* tsc -> nanosec multiplier */
	48	uint32_t shift; /* tsc -> nanosec shift/div */
	49	/* shift is overloaded with
	50	* lower 32bits of tsc_freq
	51	* on slower machines (SLOW_TSC_THRESHOLD) */
	52	uint32_t generation; /* 0 == being updated */
	53	uint32_t spare1;
	54	} rtc_nanotime_t;
	55
0c530ab8 A	56	#include <kern/etimer.h>
0c530ab8 A	57
0c530ab8	58	struct cpu_data;
6601e61a	59
593a1d5f A	60	extern void _rtc_nanotime_store(
	61	uint64_t tsc,
	62	uint64_t nsec,
	63	uint32_t scale,
	64	uint32_t shift,
	65	rtc_nanotime_t *dst);
	66
	67	extern uint64_t _rtc_nanotime_read(
	68	rtc_nanotime_t *rntp,
	69	int slow);
	70
	71	extern rtc_nanotime_t rtc_nanotime_info;
	72	#endif
	73
	74	#define SLOW_TSC_THRESHOLD 1000067800 /* TSC is too slow for regular nanotime() algorithm */
	75
	76	#if defined(__i386__)
	77	/*
	78	* Assembly snippet included in exception handlers and rtc_nanotime_read()
	79	* %edi points to nanotime info struct
	80	* %edx:%eax returns nanotime
	81	*/
	82	#define RTC_NANOTIME_READ_FAST() \
	83	0: movl RNT_GENERATION(%edi),%esi /* being updated? */ ; \
	84	testl %esi,%esi ; \
	85	jz 0b /* wait until done */ ; \
c910b4d9	86	lfence ; \
593a1d5f A	87	rdtsc ; \
	88	lfence ; \
	89	subl RNT_TSC_BASE(%edi),%eax ; \
	90	sbbl RNT_TSC_BASE+4(%edi),%edx /* tsc - tsc_base */ ; \
	91	movl RNT_SCALE(%edi),%ecx /* * scale factor */ ; \
	92	movl %edx,%ebx ; \
	93	mull %ecx ; \
	94	movl %ebx,%eax ; \
	95	movl %edx,%ebx ; \
	96	mull %ecx ; \
	97	addl %ebx,%eax ; \
	98	adcl $0,%edx ; \
	99	addl RNT_NS_BASE(%edi),%eax /* + ns_base */ ; \
	100	adcl RNT_NS_BASE+4(%edi),%edx ; \
	101	cmpl RNT_GENERATION(%edi),%esi /* check for update */ ; \
	102	jne 0b /* do it all again */
	103
	104	#elif defined(__x86_64__)
	105
	106	/*
	107	* Assembly snippet included in exception handlers and rtc_nanotime_read()
	108	* %rdi points to nanotime info struct.
	109	* %rax returns nanotime
	110	*/
	111	#define RTC_NANOTIME_READ_FAST() \
	112	0: movl RNT_GENERATION(%rdi),%esi ; \
	113	test %esi,%esi /* info updating? */ ; \
	114	jz 0b /* - wait if so */ ; \
c910b4d9	115	lfence ; \
593a1d5f A	116	rdtsc ; \
	117	lfence ; \
	118	shlq $32,%rdx ; \
	119	orq %rdx,%rax /* %rax := tsc */ ; \
	120	subq RNT_TSC_BASE(%rdi),%rax /* tsc - tsc_base */ ; \
	121	xorq %rcx,%rcx ; \
	122	movl RNT_SCALE(%rdi),%ecx ; \
	123	mulq %rcx /* delta * scale */ ; \
	124	shrdq $32,%rdx,%rax /* %rdx:%rax >>= 32 */ ; \
	125	addq RNT_NS_BASE(%rdi),%rax /* add ns_base */ ; \
	126	cmpl RNT_GENERATION(%rdi),%esi /* repeat if changed */ ; \
	127	jne 0b
	128
	129	#endif
	130
0c530ab8	131	#endif /* _I386_RTCLOCK_H_ */