/*
- * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @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. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * 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
* Please see the License for the specific language governing rights and
* limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/appleapiopts.h>
.align 2, 0x90
Lmach_absolute_time:
-
int $0x3
ret
- COMMPAGE_DESCRIPTOR(mach_absolute_time,_COMM_PAGE_ABSOLUTE_TIME,1,0)
-
+ 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)
- pushl %ebx
- pushl %esi
- pushl %edi
- pushl %ebp
- movl $(_COMM_PAGE_NANOTIME_INFO), %esi
-
- /*
- * The nanotime info consists of:
- * - base_tsc 64-bit timestamp register value
- * - base_ns 64-bit corresponding nanosecond uptime value
- * - scale 32-bit current scale multiplier
- * - shift 32-bit current shift divider
- * - check_tsc 64-bit timestamp check value
- *
- * This enables an timestamp register's value, tsc, to be converted
- * into a nanosecond nanotime value, ns:
- *
- * ns = base_ns + ((tsc - base_tsc) * scale >> shift)
- *
- * The kernel updates this every tick or whenever a performance
- * speed-step changes the scaling. To avoid locking, a duplicated
- * sequence counting scheme is used. The base_tsc value is updated
- * whenever the info starts to be changed, and check_tsc is updated
- * to the same value at the end of the update. The regularity of
- * update ensures that (tsc - base_tsc) is a 32-bit quantity.
- * When a conversion is performed, we read base_tsc before we start
- * and check_tsc at the end -- if there's a mis-match we repeat.
- * It's sufficient to compare only the low-order 32-bits.
- */
+/* 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:
- //
- // Read nanotime info and stash in registers.
- //
- movl NANOTIME_BASE_TSC(%esi), %ebx // ebx := lo(base_tsc)
- movl NANOTIME_BASE_NS(%esi), %ebp
- movl NANOTIME_BASE_NS+4(%esi), %edi // edi:ebp := base_ns
- movl NANOTIME_SHIFT(%esi), %ecx // ecx := shift
- //
- // Read timestamp register (tsc) and calculate delta.
- //
- rdtsc // edx:eax := tsc
- subl %ebx, %eax // eax := (tsc - base_tsc)
- movl NANOTIME_SCALE(%esi), %edx // edx := shift
- //
- // Check for consistency and re-read if necessary.
- //
- cmpl NANOTIME_CHECK_TSC(%esi), %ebx
+ 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
-
- //
- // edx:eax := ((tsc - base_tsc) * scale)
- //
- mull %edx
-
- //
- // eax := ((tsc - base_tsc) * scale >> shift)
- //
- shrdl %cl, %edx, %eax
- andb $32, %cl
- cmovnel %edx, %eax // %eax := %edx if shift == 32
- xorl %edx, %edx
-
- //
- // Add base_ns:
- // edx:eax = (base_ns + ((tsc - base_tsc) * scale >> shift))
- //
- addl %ebp, %eax
- adcl %edi, %edx
-
- popl %ebp
- popl %edi
- popl %esi
- popl %ebx
+ popq %rbp
ret
- COMMPAGE_DESCRIPTOR(nanotime,_COMM_PAGE_NANOTIME,1,0)
+ COMMPAGE_DESCRIPTOR(nanotime_64,_COMM_PAGE_NANOTIME,0,0)
+ COMMPAGE_DESCRIPTOR(old_nanotime_64,_COMM_PAGE_OLD_NANOTIME,0,0)
projects / apple / xnu.git / blobdiff