c - How to update an array in vectorized assembly(AVX)? - 


inline void addition(double * x, const double * vx,uint32_t size){     /*for (uint32_t i=0;i<size;++i){         x[i] = x[i] + vx[i];     }*/     __asm__ __volatile__ (     "1: \n\t"       "vmovupd    -32(%0), %%ymm1\n\t"     "vmovupd    (%0), %%ymm0\n\t"     "vaddpd     -32(%1), %%ymm0, %%ymm0\n\t"     "vaddpd     (%1), %%ymm1, %%ymm1\n\t"      "vmovupd    %%ymm0, -32(%0)\n\t"     "vmovupd    %%ymm1, (%0)\n\t"      "addq   $128, %0\n\t"     "addq   $128, %1\n\t"      "addl   $-8, %2\n\t"     "jne    1b"         :          : "r" (x),"r"(vx),"r"(size)         : "ymm0", "ymm1"     ); }

i practicing assembly(avx instructions) right write above piece of code in inline assembly replace c code in original function(which commented out). compiling process successful when try run program, error happens: bus error: 10 thoughts bug? didn't know what's wrong here. compiler version clang 602.0.53. thank you!

inline assembly complicated beast, if want practice avx assembly use separate asm file don't have put compiler. in exchange, need observe calling convention though.

you have issues constraints. example, change input registers without telling compiler , can cause sorts of weird problems elsewhere in compiler generated code. need specify memory clobber obvious reasons.

also, learn use debugger can find exact cause of problems , fix own code.

failing that, @ least comment code can figure out intentions. in case, particularly puzzled why use -32 offset address before array. think wanted +32 there. using 2 avx registers @ 32 bytes each, of course need advance pointers 64 not 128. have ymm0 , ymm1 swapped in initial load.

this code seems work fine me:

#include <stdio.h> #include <stdint.h>  inline void addition(double * x, const double * vx,uint32_t size){     /*for (uint32_t i=0;i<size;++i){         x[i] = x[i] + vx[i];     }*/     __asm__ __volatile__ (     "1: \n\t"       "vmovupd    32(%0), %%ymm0\n\t"     "vmovupd    (%0), %%ymm1\n\t"     "vaddpd     32(%1), %%ymm0, %%ymm0\n\t"     "vaddpd     (%1), %%ymm1, %%ymm1\n\t"      "vmovupd    %%ymm0, 32(%0)\n\t"     "vmovupd    %%ymm1, (%0)\n\t"      "addq   $64, %0\n\t"     "addq   $64, %1\n\t"      "addl   $-8, %2\n\t"     "jne    1b"         : "+r" (x),"+r"(vx),"+r"(size)         :         : "ymm0", "ymm1", "memory"     ); }  int main() {     double x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };     double vx[] = { 9, 10, 11, 12, 13, 14, 15, 16 };     int i;     addition(x, vx, 8);     for(i = 0; < 8; i++) printf("%g ", x[i]);     putchar('\n');     return 0; }

Comments

Post a Comment

Popular posts from this blog

javascript - jQuery: Add class depending on URL in the best way -

i have html progress meter: <div class="col-md-3" style="margin-left: -20px;"> <div class="progress-pos active" id="progess-1"> <div class="progress-pos-inner"> login </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-2"> <div class="progress-pos-inner"> scan items </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-3"> <div class="progress-pos-inner"> confirm address </div> </div> </div> <div class="col-md-3 progress-pos-container"> <div class="progress-pos" id="progess-4"> <div class="progress-pos-in
Read more

caching - How to check if a url path exists in the service worker cache -

i need check if particular url path exists in service worker cache. example, suppose url is: /myserviceworker/service?a=110&b=70 this url exists in cache, there many of them different values of , b. now, suppose want refresh of these urls, how can that? i want know how access key values service worker cache. if know key, plan follows: var url = new url(key); if(url.pathname === "\/myserviceworker/service") refetch key but not sure how cache key , in format is. mean, string or url? cache api has match() method returns promise resolving in response object if match or undefined if no match exists. second parameter object can specify ignoresearch not take account url parameters. the ignoresearch option supported firefox ( chrome status here ). in other hand, retrieve cache entries, can use keys() method.
Read more

Redirect to a HTTPS version using .htaccess -

i need modify .htaccess file redirect urls https version without "www". http://example.com --> https://example.com http://www.example.com --> https://example.com https://www.example.com --> https://example.com this how .htaccess file looks like: rewriteengine on rewritecond %{request_filename} !-d rewritecond %{request_filename} !-f rewriterule ^(.*)$ redirect.php?id=$1&page=$2 [qsa,l] what modifications need make .htaccess in order forward https without "www"? it depends on doing current code. looks file called redirect trying display php page seo friendly url. think might confusing people. anyway, need , force https without www, need 1 more rule above. also second rule needs two capture groups in rewriterule test string because wanting 2 different values using $1 , $2 references. rewriteengine on #rediect www non www and/or http https --- combinations. rewritecond %{http_host} !^example\.com [nc,or] rewritecond %{https} !^
Read more