1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
14 unsafe fn next_power_of_2(n: u32) -> u32 {
16 asm!("dec $0" : "+rm"(tmp) :: "cc");
23 : "+&rm"(tmp), "+{ecx}"(shift) : "r"(tmp) : "cc"
26 asm!("inc $0" : "+rm"(tmp) :: "cc");
30 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
33 assert_eq!(64, next_power_of_2(37));
34 assert_eq!(2147483648, next_power_of_2(2147483647));
40 // Treat the output as initialization.
45 : "=r"(x), "+r"(y) : "i"(3u), "ir"(7u) : "cc"
55 // Assignment to mutable.
57 // Forbids the use of a single register by both operands.
58 asm!("shr $$2, $1; add $1, $0" : "+&r"(x) : "r"(x) : "cc");
63 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]