зеркало из https://github.com/mozilla/gecko-dev.git
117 строки
3.5 KiB
C
117 строки
3.5 KiB
C
/********************************************************************
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* *
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* THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE. *
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* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
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* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
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* *
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* THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2010 *
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* by the Xiph.Org Foundation and contributors http://www.xiph.org/ *
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* *
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********************************************************************
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CPU capability detection for ARM processors.
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function:
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last mod: $Id: cpu.c 17344 2010-07-21 01:42:18Z tterribe $
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********************************************************************/
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#include "armcpu.h"
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#if !defined(OC_ARM_ASM)|| \
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!defined(OC_ARM_ASM_EDSP)&&!defined(OC_ARM_ASM_ARMV6)&& \
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!defined(OC_ARM_ASM_NEON)
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ogg_uint32_t oc_cpu_flags_get(void){
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return 0;
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}
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#elif defined(_MSC_VER)
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/*For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.*/
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# define WIN32_LEAN_AND_MEAN
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# define WIN32_EXTRA_LEAN
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# include <windows.h>
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ogg_uint32_t oc_cpu_flags_get(void){
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ogg_uint32_t flags;
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flags=0;
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/*MSVC has no inline __asm support for ARM, but it does let you __emit
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instructions via their assembled hex code.
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All of these instructions should be essentially nops.*/
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# if defined(OC_ARM_ASM_EDSP)
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__try{
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/*PLD [r13]*/
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__emit(0xF5DDF000);
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flags|=OC_CPU_ARM_EDSP;
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}
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__except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){
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/*Ignore exception.*/
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}
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# if defined(OC_ARM_ASM_MEDIA)
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__try{
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/*SHADD8 r3,r3,r3*/
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__emit(0xE6333F93);
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flags|=OC_CPU_ARM_MEDIA;
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}
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__except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){
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/*Ignore exception.*/
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}
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# if defined(OC_ARM_ASM_NEON)
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__try{
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/*VORR q0,q0,q0*/
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__emit(0xF2200150);
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flags|=OC_CPU_ARM_NEON;
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}
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__except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){
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/*Ignore exception.*/
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}
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# endif
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# endif
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# endif
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return flags;
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}
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#elif defined(__linux__)
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# include <stdio.h>
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# include <stdlib.h>
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# include <string.h>
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ogg_uint32_t oc_cpu_flags_get(void){
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ogg_uint32_t flags;
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FILE *fin;
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flags=0;
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/*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
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Android.
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This also means that detection will fail in Scratchbox.*/
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fin=fopen("/proc/cpuinfo","r");
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if(fin!=NULL){
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/*512 should be enough for anybody (it's even enough for all the flags that
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x86 has accumulated... so far).*/
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char buf[512];
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while(fgets(buf,511,fin)!=NULL){
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if(memcmp(buf,"Features",8)==0){
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char *p;
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p=strstr(buf," edsp");
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if(p!=NULL&&(p[5]==' '||p[5]=='\n'))flags|=OC_CPU_ARM_EDSP;
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p=strstr(buf," neon");
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if(p!=NULL&&(p[5]==' '||p[5]=='\n'))flags|=OC_CPU_ARM_NEON;
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}
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if(memcmp(buf,"CPU architecture:",17)==0){
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int version;
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version=atoi(buf+17);
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if(version>=6)flags|=OC_CPU_ARM_MEDIA;
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}
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}
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fclose(fin);
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}
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return flags;
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}
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#else
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/*The feature registers which can tell us what the processor supports are
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accessible in priveleged modes only, so we can't have a general user-space
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detection method like on x86.*/
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# error "Configured to use ARM asm but no CPU detection method available for " \
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"your platform. Reconfigure with --disable-asm (or send patches)."
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#endif
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