/* * Copyright (c) 2007, 2008, 2009, 2010 Apple Inc. All rights reserved. * * @APPLE_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. * * 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_LICENSE_HEADER_END@ */ #if defined(__i386__) || defined(__x86_64__) #include <stdlib.h> #include <machine/cpu_capabilities.h> #include "platfunc.h" #define PLAT_CAP_MASK (kHasMMX | kHasSSE | kHasSSE2 | kHasSSE3 | kCache32 | kCache64 | kCache128 | kFastThreadLocalStorage | kHasSupplementalSSE3 | k64Bit | kHasSSE4_1 | kHasSSE4_2 | kHasAES | kInOrderPipeline | kSlow | kUP) inline static int __get_cpu_capabilities() { return *((int32_t*)_COMM_PAGE_CPU_CAPABILITIES); } inline static int num_cpus(int capabilities) { return (capabilities & kNumCPUs) >> kNumCPUsShift; } /* TODO: If 8151810 is fixed (or full support for visibility("internal") is added), change this to visibility("internal") */ void __attribute__((visibility("hidden"))) *find_platform_function(const platfunc_descriptor *descriptors[]) { int cap = __get_cpu_capabilities(), have_cpus = num_cpus(cap); for (int i = 0; descriptors[i] != 0; i++) { int musthave_cpus = num_cpus(descriptors[i]->musthave), canthave_cpus = num_cpus(descriptors[i]->canthave); uint32_t musthave = descriptors[i]->musthave & PLAT_CAP_MASK, canthave = descriptors[i]->canthave & PLAT_CAP_MASK; /* First check that the CPU supports all the features that are in musthave */ if ((musthave & cap) != musthave) continue; /* Now check that the CPU doesn't have any of the features that are in canthave */ if ((canthave & cap) != 0) continue; /* Special case check for the number of CPUs. */ /* TODO: Should there be a way to specify < or > num cpus? */ if (musthave_cpus != 0 && have_cpus != musthave_cpus) continue; if (canthave_cpus != 0 && have_cpus == canthave_cpus) continue; /* otherwise, we have found our preferred implementation */ return descriptors[i]->address; } /* We didn't find an acceptable implementation. (bug in data structures!) */ return NULL; } #endif