Warning

This post was published 123 days ago. The information described in this article may have changed.

Info

This post is auto-generated from RSS feed The Rust Programming Language Forum - Latest topics. Source: Arm cortex-m4 #[inline(never)] creates bigger firmware size?

I have this one shot timer function from Discovery book stm32f3 discovery:

#[inline(never)]
fn delay(tim6: &tim6::RegisterBlock, ms: u16) {
    // Set the timer to go off in `ms` ticks
    // 1 tick = 1 ms
    tim6.arr.write(|w| w.arr().bits(ms));
    // CEN: Enable the counter
    tim6.cr1.modify(|_, w| w.cen().set_bit());
    // Wait until the alarm goes off (until the update event occurs)
    while !tim6.sr.read().uif().bit_is_set() {}
    // Clear the update event flag
    tim6.sr.modify(|_, w| w.uif().clear_bit());
}

This function then gets called repeatedly and infinitely from the main loop.

When I check its size with GNU binutils size command. Release size:

text data bss dec hex filename
5916 0 4 5920 1720 target/thumbv7em-none-eabihf/release/clocks-and-timers

When I remove #[inline(never)], release size:

text data bss dec hex filename
5828 0 4 5832 16c8 target/thumbv7em-none-eabihf/release/clocks-and-timers

So it’s optimized slightly better without inline never?

4 posts - 3 participants

Read full topic

🏷️ Rust_feed