commpage_mach_absolute_time.s [plain text]
/*
* 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>
#include <machine/commpage.h>
#include <i386/asm.h>
#include <assym.s>
.text
.align 2, 0x90
Lmach_absolute_time:
int $0x3
ret
COMMPAGE_DESCRIPTOR(mach_absolute_time,_COMM_PAGE_ABSOLUTE_TIME,0,0)
/* return nanotime in %edx:%eax */
Lnanotime:
pushl %ebp
movl %esp,%ebp
pushl %esi
pushl %ebx
0:
movl _COMM_PAGE_NT_GENERATION,%esi /* get generation (0 if being changed) */
testl %esi,%esi /* if being updated, loop until stable */
jz 0b
rdtsc /* get TSC in %edx:%eax */
subl _COMM_PAGE_NT_TSC_BASE,%eax
sbbl _COMM_PAGE_NT_TSC_BASE+4,%edx
movl _COMM_PAGE_NT_SCALE,%ecx
movl %edx,%ebx
mull %ecx
movl %ebx,%eax
movl %edx,%ebx
mull %ecx
addl %ebx,%eax
adcl $0,%edx
addl _COMM_PAGE_NT_NS_BASE,%eax
adcl _COMM_PAGE_NT_NS_BASE+4,%edx
cmpl _COMM_PAGE_NT_GENERATION,%esi /* have the parameters changed? */
jne 0b /* yes, loop until stable */
popl %ebx
popl %esi
popl %ebp
ret
COMMPAGE_DESCRIPTOR(nanotime,_COMM_PAGE_NANOTIME,0,kSlow)
/* nanotime routine for machines slower than ~1Gz (SLOW_TSC_THRESHOLD) */
Lnanotime_slow:
push %ebp
mov %esp,%ebp
push %esi
push %edi
push %ebx
0:
movl _COMM_PAGE_NT_GENERATION,%esi
testl %esi,%esi /* if generation is 0, data being changed */
jz 0b /* so loop until stable */
rdtsc /* get TSC in %edx:%eax */
subl _COMM_PAGE_NT_TSC_BASE,%eax
sbbl _COMM_PAGE_NT_TSC_BASE+4,%edx
pushl %esi /* save generation */
/*
* Do the math to convert tsc ticks to nanoseconds. We first
* do long multiply of 1 billion times the tsc. Then we do
* long division by the tsc frequency
*/
mov $1000000000, %ecx /* number of nanoseconds in a second */
mov %edx, %ebx
mul %ecx
mov %edx, %edi
mov %eax, %esi
mov %ebx, %eax
mul %ecx
add %edi, %eax
adc $0, %edx /* result in edx:eax:esi */
mov %eax, %edi
mov _COMM_PAGE_NT_SHIFT,%ecx /* overloaded as the low 32 tscFreq */
xor %eax, %eax
xchg %edx, %eax
div %ecx
xor %eax, %eax
mov %edi, %eax
div %ecx
mov %eax, %ebx
mov %esi, %eax
div %ecx
mov %ebx, %edx /* result in edx:eax */
popl %esi /* recover generation */
add _COMM_PAGE_NT_NS_BASE,%eax
adc _COMM_PAGE_NT_NS_BASE+4,%edx
cmpl _COMM_PAGE_NT_GENERATION,%esi /* have the parameters changed? */
jne 0b /* yes, loop until stable */
pop %ebx
pop %edi
pop %esi
pop %ebp
ret /* result in edx:eax */
COMMPAGE_DESCRIPTOR(nanotime_slow,_COMM_PAGE_NANOTIME,kSlow,0)
/* The 64-bit version. We return the 64-bit nanotime in %rax,
* and by convention we must preserve %r9, %r10, and %r11.
*/
.text
.align 2
.code64
Lnanotime_64: // NB: must preserve r9, r10, and r11
pushq %rbp // set up a frame for backtraces
movq %rsp,%rbp
movq $_COMM_PAGE_32_TO_64(_COMM_PAGE_TIME_DATA_START),%rsi
1:
movl _NT_GENERATION(%rsi),%r8d // get generation
testl %r8d,%r8d // if 0, data is being changed...
jz 1b // ...so loop until stable
rdtsc // edx:eax := tsc
shlq $32,%rdx // rax := ((edx << 32) | eax), ie 64-bit tsc
orq %rdx,%rax
subq _NT_TSC_BASE(%rsi), %rax // rax := (tsc - base_tsc)
movl _NT_SCALE(%rsi),%ecx
mulq %rcx // rdx:rax := (tsc - base_tsc) * scale
shrdq $32,%rdx,%rax // _COMM_PAGE_NT_SHIFT is always 32
addq _NT_NS_BASE(%rsi),%rax // (((tsc - base_tsc) * scale) >> 32) + ns_base
cmpl _NT_GENERATION(%rsi),%r8d // did the data change during computation?
jne 1b
popq %rbp
ret
COMMPAGE_DESCRIPTOR(nanotime_64,_COMM_PAGE_NANOTIME,0,kSlow)