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acle::hints: use llvm.{arm,aarch64.hint}

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addresses https://github.com/rust-lang-nursery/stdsimd/pull/557#discussion_r255250217
This commit is contained in:
Jorge Aparicio 2019-02-13 17:27:48 +01:00 • committed by gnzlbg
parent 13d35372ec
commit 766fac9afa
1 changed files with 20 additions and 6 deletions
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26
library/stdarch/crates/core_arch/src/acle/hints.rs
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@ -12,7 +12,7 @@
#[cfg(any(target_feature = "v6k", target_arch = "aarch64"))]
#[inline(always)]
pub unsafe fn __wfi() {
asm!("WFI" : : : : "volatile")
hint(HINT_WFI);
}
/// Generates a WFE (wait for event) hint instruction, or nothing.
@ -25,7 +25,7 @@ pub unsafe fn __wfi() {
#[cfg(any(target_feature = "v6k", target_arch = "aarch64"))]
#[inline(always)]
pub unsafe fn __wfe() {
asm!("WFE" : : : : "volatile")
hint(HINT_WFE);
}
/// Generates a SEV (send a global event) hint instruction.
@ -37,7 +37,7 @@ pub unsafe fn __wfe() {
#[cfg(any(target_feature = "v6k", target_arch = "aarch64"))]
#[inline(always)]
pub unsafe fn __sev() {
asm!("SEV" : : : : "volatile")
hint(HINT_SEV);
}
/// Generates a send a local event hint instruction.
@ -49,7 +49,7 @@ pub unsafe fn __sev() {
#[cfg(target_arch = "aarch64")]
#[inline(always)]
pub unsafe fn __sevl() {
asm!("SEVL" : : : : "volatile")
hint(HINT_SEVL);
}
/// Generates a YIELD hint instruction.
@ -62,7 +62,7 @@ pub unsafe fn __sevl() {
#[cfg(any(target_feature = "v6k", target_arch = "aarch64"))]
#[inline(always)]
pub unsafe fn __yield() {
asm!("YIELD" : : : : "volatile")
hint(HINT_YIELD);
}
/// Generates a DBG instruction.
@ -111,5 +111,19 @@ pub unsafe fn __dbg(imm4: u32) {
/// will increase execution time.
#[inline(always)]
pub unsafe fn __nop() {
asm!("NOP" : : : : "volatile")
hint(HINT_NOP);
}
extern "C" {
#[cfg_attr(target_arch = "aarch64", link_name = "llvm.aarch64.hint")]
#[cfg_attr(target_arch = "arm", link_name = "llvm.arm.hint")]
fn hint(_: i32);
}
// from LLVM 7.0.1's lib/Target/ARM/{ARMInstrThumb,ARMInstrInfo,ARMInstrThumb2}.td
const HINT_NOP: i32 = 0;
const HINT_YIELD: i32 = 1;
const HINT_WFE: i32 = 2;
const HINT_WFI: i32 = 3;
const HINT_SEV: i32 = 4;
const HINT_SEVL: i32 = 5;