From f04e448e35d92a446a089f2fb2b7dcbd00454306 Mon Sep 17 00:00:00 2001 From: Jorge Aparicio Date: Fri, 18 May 2018 19:47:53 +0200 Subject: fix asm! clobber, no inline-asm support, 4 insn per cycle --- src/asm.rs | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'src') diff --git a/src/asm.rs b/src/asm.rs index 4b5d88c..fd1ce7c 100644 --- a/src/asm.rs +++ b/src/asm.rs @@ -24,26 +24,37 @@ pub fn bkpt() { } } -/// Blocks the program for at least `n` instruction cycles +/// Blocks the program for *at least* `n` instruction cycles /// /// This is implemented in assembly so its execution time is the same regardless of the optimization /// level. /// /// NOTE that the delay can take much longer if interrupts are serviced during its execution. -#[inline(never)] +#[inline] pub fn delay(_n: u32) { match () { - #[cfg(target_arch = "arm")] + #[cfg(all(cortex_m, feature = "inline-asm"))] () => unsafe { asm!("1: + nop subs $0, $$1 bne.n 1b" + : "+r"(_n / 4 + 1) : - : "r"(_n / 3 + 1) : : "volatile"); }, - #[cfg(not(target_arch = "arm"))] + + #[cfg(all(cortex_m, not(feature = "inline-asm")))] + () => unsafe { + extern "C" { + fn __delay(n: u32); + } + + __delay(_n / 4 + 1); + }, + + #[cfg(not(cortex_m))] () => unimplemented!(), } } -- cgit v1.2.3