01 // Compute scalar product in C:
02 float scalarproduct(float x[], float y[])
03 {
04   return x[0]*y[0] + x[1]*y[1] + x[2]*y[2] + x[3]*y[3];
05 }
06
07 // Compute scalar product in Assembler:
08 float scalarproductAssembler(float x[], float y[])
09 {
10   vector tmp;
11   asm(
12      "movl   %1,      %%esi;"
13      "movl   %2,      %%edi;"
14      "movaps (%%esi), %%xmm0;"
15      "mulps  (%%edi), %%xmm0;"
16      "movaps %%xmm0,  %0;"
17     :"=g"(tmp)        /* Output */
18     :"r"(x),"r"(y)    /* Input */
19   );
20   return tmp.f[0] + tmp.f[1] + tmp.f[2] + tmp.f[3];
21 }