Now that's really easy. What does this code do?
Optimizing clang 3.4, LLVM 3.4, AT&T syntax:
f: # @f
xorps %xmm0, %xmm0
movups %xmm0, 240(%rdi)
movups %xmm0, 224(%rdi)
movups %xmm0, 208(%rdi)
movups %xmm0, 192(%rdi)
movups %xmm0, 176(%rdi)
movups %xmm0, 160(%rdi)
movups %xmm0, 144(%rdi)
movups %xmm0, 128(%rdi)
movups %xmm0, 112(%rdi)
movups %xmm0, 96(%rdi)
movups %xmm0, 80(%rdi)
movups %xmm0, 64(%rdi)
movups %xmm0, 48(%rdi)
movups %xmm0, 32(%rdi)
movups %xmm0, 16(%rdi)
movups %xmm0, (%rdi)
ret
More challenges: challenges.re; about solutions: challenges.re/#Solutions.