rqsrt.rs
| fn libc_rsqrt(f: &f32) -> f32 { | |
| 1.0/f32::sqrt(*f) | |
| } | |
| fn llvm_rsqrt(f: &f32) -> f32 { | |
| 1.0/core::unstable::intrinsics::sqrtf32(*f) | |
| } | |
| fn asm_rsqrt(f: &f32) -> f32 { | |
| let mut b = &0.0f32; | |
| unsafe { | |
| asm!("rsqrtss ($0), %xmm0\n\t\ | |
| movss %xmm0, ($0)" | |
| :"=r"(b) | |
| :"0"(f) | |
| :"xmm0" | |
| ); | |
| *b | |
| } | |
| } | |
| fn main() { | |
| io::println(fmt!("libc: %?", libc_rsqrt(&64.0))); | |
| io::println(fmt!("llvm: %?", llvm_rsqrt(&64.0))); | |
| io::println(fmt!("rsqrt: %?", asm_rsqrt(&64.0))); | |
| } |