commpage_mach_absolute_time.s [plain text]
/*
* 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>
#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)
/* Nanotime is being moved out of the way of bcopy in the commpage.
* First we put it in both places, old and new. Then, when all the build
* trains have rebuilt libSystem, we can remove the deprecated instance.
*/
/* return nanotime in %edx:%eax */
Lold_nanotime:
Lnanotime:
push %ebp
mov %esp,%ebp
push %esi
push %edi
push %ebx
0:
mov _COMM_PAGE_NT_TSC_BASE,%esi
mov _COMM_PAGE_NT_TSC_BASE+4,%edi
rdtsc
sub %esi,%eax
sbb %edi,%edx
mov _COMM_PAGE_NT_SCALE,%ecx
mov %edx,%ebx
mull %ecx
mov %ebx,%eax
mov %edx,%ebx
mull %ecx
add %ebx,%eax
adc $0,%edx
add _COMM_PAGE_NT_NS_BASE,%eax
adc _COMM_PAGE_NT_NS_BASE+4,%edx
cmp _COMM_PAGE_NT_TSC_BASE,%esi
jne 0b
cmp _COMM_PAGE_NT_TSC_BASE+4,%edi
jne 0b
pop %ebx
pop %edi
pop %esi
pop %ebp
ret
COMMPAGE_DESCRIPTOR(nanotime,_COMM_PAGE_NANOTIME,0,0)
COMMPAGE_DESCRIPTOR(old_nanotime,_COMM_PAGE_OLD_NANOTIME,0,0)
/* 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
Lold_nanotime_64:
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_NT_TSC_BASE),%rsi
1:
movq _NT_TSC_BASE(%rsi),%r8 // r8 := base_tsc
rdtsc // edx:eax := tsc
shlq $32,%rdx // rax := ((edx << 32) | eax), ie 64-bit tsc
orq %rdx,%rax
subq %r8, %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
cmpq _NT_TSC_BASE(%rsi),%r8 // did the data change during computation?
jne 1b
popq %rbp
ret
COMMPAGE_DESCRIPTOR(nanotime_64,_COMM_PAGE_NANOTIME,0,0)
COMMPAGE_DESCRIPTOR(old_nanotime_64,_COMM_PAGE_OLD_NANOTIME,0,0)