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