blinky_delay.rs

#![no_main]
#![no_std]

#[allow(unused)]
use panic_halt;

use stm32f0xx_hal as hal;

use crate::hal::delay::Delay;
use crate::hal::prelude::*;
use crate::hal::stm32;

use cortex_m::peripheral::Peripherals;
use cortex_m_rt::entry;

#[entry]
fn main() -> ! {
    if let (Some(p), Some(cp)) = (stm32::Peripherals::take(), Peripherals::take()) {
        let gpioa = p.GPIOA.split();

        /* (Re-)configure PA1 as output */
        let mut led = gpioa.pa1.into_push_pull_output();

        /* Constrain clocking registers */
        let rcc = p.RCC.constrain();

        /* Configure clock to 8 MHz (i.e. the default) and freeze it */
        let clocks = rcc.cfgr.sysclk(8.mhz()).freeze();

        /* Get delay provider */
        let mut delay = Delay::new(cp.SYST, clocks);

        loop {
            led.toggle();
            delay.delay_ms(1_000_u16);
        }
    }

    loop {
        continue;
    }
}

blinky_delay_udiv.rs

#![no_main]
#![no_std]

#[allow(unused)]
use panic_halt;

use stm32f0xx_hal as hal;

use crate::hal::delay::Delay;
use crate::hal::prelude::*;
use crate::hal::stm32;

use cortex_m::peripheral::Peripherals;
use cortex_m_rt::entry;

#[entry]
fn main() -> ! {
    if let (Some(p), Some(cp)) = (stm32::Peripherals::take(), Peripherals::take()) {
        let gpioa = p.GPIOA.split();

        /* (Re-)configure PA1 as output */
        let mut led = gpioa.pa1.into_push_pull_output();

        /* Constrain clocking registers */
        let rcc = p.RCC.constrain();

        /* Configure clock to 8 MHz (i.e. the default) and freeze it */
        let clocks = rcc.cfgr.sysclk(8.mhz()).freeze();

        /* Get delay provider */
        let mut delay = Delay::new(cp.SYST, clocks);

        loop {
            led.set_high();
            delay.delay_ms(1_000_u16);
            led.set_low();
            delay.delay_ms(1_000_u16);
        }
    }

    loop {
        continue;
    }
}

bloat comparison

Bloat for example blinky_delay
Compiling ...
Analyzing target/thumbv6m-none-eabi/release/examples/blinky_delay

File  .text Size       Crate Name
0.0%   0.0%   0B             [0 Others]
0.1%  39.7% 236B   [Unknown] main
0.1%  24.2% 144B   [Unknown] __udivmodsi4
0.1%  21.2% 126B   [Unknown] __clzsi2
0.0%  10.8%  64B cortex_m_rt Reset
0.0%   3.0%  18B   [Unknown] __aeabi_uidivmod
0.0%   0.3%   2B cortex_m_rt HardFault_
0.0%   0.3%   2B cortex_m_rt DefaultPreInit
0.0%   0.3%   2B cortex_m_rt DefaultHandler_
0.3% 100.0% 594B             .text section size, the file size is 193.4KiB

Bloat for example blinky_delay_udiv
Compiling ...
Analyzing target/thumbv6m-none-eabi/release/examples/blinky_delay_udiv

File  .text Size         Crate Name
0.0%   0.0%   0B               [0 Others]
0.1%  25.4% 212B     [Unknown] main
0.1%  17.3% 144B     [Unknown] __udivmodsi4
0.1%  15.6% 130B     [Unknown] __aeabi_uidiv
0.1%  15.1% 126B     [Unknown] __clzsi2
0.1%  14.4% 120B stm32f0xx_hal <stm32f0xx_hal::delay::Delay as embedded_hal::blocking::delay::DelayMs<u16>>::delay_ms
0.0%   7.7%  64B   cortex_m_rt Reset
0.0%   2.2%  18B     [Unknown] __aeabi_uidivmod
0.0%   0.7%   6B           std core::panicking::panic
0.0%   0.7%   6B           std core::panicking::panic_fmt
0.0%   0.2%   2B   cortex_m_rt HardFault_
0.0%   0.2%   2B    panic_halt rust_begin_unwind
0.0%   0.2%   2B   cortex_m_rt DefaultPreInit
0.0%   0.2%   2B   cortex_m_rt DefaultHandler_
0.4% 100.0% 834B               .text section size, the file size is 195.4KiB