gcc :) -O3 for better grip

0000000000000000 <c_is_faster_than_asm_a>:
   0:   48 63 d2                movsxd rdx,edx
   3:   31 c0                   xor    eax,eax
   5:   48 c1 ea 04             shr    rdx,0x4
   9:   48 85 d2                test   rdx,rdx
   c:   74 52                   je     60 <c_is_faster_than_asm_a+0x60>
   e:   66 90                   xchg   ax,ax
  10:   0f 28 06                movaps xmm0,XMMWORD PTR [rsi]
  13:   48 83 c0 08             add    rax,0x8
  17:   48 83 ee 80             sub    rsi,0xffffffffffffff80
  1b:   48 83 ef 80             sub    rdi,0xffffffffffffff80
  1f:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  23:   0f 28 46 90             movaps xmm0,XMMWORD PTR [rsi-0x70]
  27:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  2b:   0f 28 46 a0             movaps xmm0,XMMWORD PTR [rsi-0x60]
  2f:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  33:   0f 28 46 b0             movaps xmm0,XMMWORD PTR [rsi-0x50]
  37:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  3b:   0f 28 46 c0             movaps xmm0,XMMWORD PTR [rsi-0x40]
  3f:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  43:   0f 28 46 d0             movaps xmm0,XMMWORD PTR [rsi-0x30]
  47:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  4b:   0f 28 46 e0             movaps xmm0,XMMWORD PTR [rsi-0x20]
  4f:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  53:   0f 28 46 f0             movaps xmm0,XMMWORD PTR [rsi-0x10]
  57:   0f 29 47 80             movaps XMMWORD PTR [rdi-0x80],xmm0
  5b:   48 39 c2                cmp    rdx,rax
  5e:   77 b0                   ja     10 <c_is_faster_than_asm_a+0x10>
  60:   f3 c3                   repz ret