X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/ff6e181ae92fc6f1e89841290f461d1f2f9badd9..89b3af67bb32e691275bf6fa803d1834b2284115:/osfmk/i386/commpage/commpage_mach_absolute_time.s diff --git a/osfmk/i386/commpage/commpage_mach_absolute_time.s b/osfmk/i386/commpage/commpage_mach_absolute_time.s index 1d1ff75e5..1cacdb5b2 100644 --- a/osfmk/i386/commpage/commpage_mach_absolute_time.s +++ b/osfmk/i386/commpage/commpage_mach_absolute_time.s @@ -1,14 +1,19 @@ /* - * 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 @@ -18,7 +23,7 @@ * 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 @@ -32,89 +37,87 @@ .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)