From 1efbfa56ca8aa07477e5092a2794c1bceedc38a1 Mon Sep 17 00:00:00 2001
From: 97gushan <97gustavh@gmail.com>
Date: Wed, 1 Apr 2020 10:42:44 +0200
Subject: [PATCH] bare5_2
---
examples/bare5.rs | 67 ++++++++++++++++++++++++++++-------------------
1 file changed, 40 insertions(+), 27 deletions(-)
diff --git a/examples/bare5.rs b/examples/bare5.rs
index 9282a87..32554e3 100644
--- a/examples/bare5.rs
+++ b/examples/bare5.rs
@@ -13,6 +13,8 @@ extern crate panic_halt;
extern crate cortex_m;
use cortex_m_rt::entry;
+use cortex_m_semihosting::hprintln;
+
// C like API...
mod stm32f40x {
@@ -57,12 +59,17 @@ mod stm32f40x {
// width (field width)
// value (new value that the field should take)
//
- // impl VolatileCell<u32> {
- // #[inline(always)]
- // pub fn modify(&self, offset: u8, width: u8, value: u32) {
- // // your code here
- // }
- // }
+ impl VolatileCell<u32> {
+ #[inline(always)]
+ pub fn modify(&self, offset: u8, width: u8, value: u32) {
+ let mask: u32 = (1 << width) - 1;
+ let masked_value = value & mask;
+
+ let r = self.read() & !(mask << offset);
+
+ self.write(r | masked_value << offset);
+ }
+ }
#[repr(C)]
#[allow(non_snake_case)]
@@ -141,27 +148,29 @@ fn wait(i: u32) {
}
// simple test of Your `modify`
-//fn test() {
-// let t:VolatileCell<u32> = unsafe { core::mem::uninitialized() };
-// t.write(0);
-// assert!(t.read() == 0);
-// t.modify(3, 3, 0b10101);
-// //
-// // 10101
-// // ..0111000
-// // ---------
-// // 000101000
-// assert!(t.read() == 0b101 << 3);
-// t.modify(4, 3, 0b10001);
-// // 000101000
-// // 111
-// // 001
-// // 000011000
-// assert!(t.read() == 0b011 << 3);
+fn test() {
+ let t:VolatileCell<u32> = unsafe { core::mem::uninitialized() };
+ t.write(0);
+ assert!(t.read() == 0);
+ t.modify(3, 3, 0b10101);
+ //
+ // 10101
+ // ..0111000
+ // ---------
+ // 000101000
+ hprintln!("{:?}", t.read()).unwrap();
+ hprintln!("{:?}", 0b101 << 3);
+ assert!(t.read() == 0b101 << 3);
+ t.modify(4, 3, 0b10001);
+ // 000101000
+ // 111
+ // 001
+ // 000011000
+ assert!(t.read() == 0b011 << 3);
// if << is used, your code will panic in dev (debug), but not in release mode
// t.modify(32, 3, 1);
-//}
+}
// system startup, can be hidden from the user
#[entry]
@@ -169,7 +178,7 @@ fn main() -> ! {
let rcc = unsafe { &mut *RCC::get() }; // get the reference to RCC in memory
let gpioa = unsafe { &mut *GPIOA::get() }; // get the reference to GPIOA in memory
- // test(); // uncomment to run test
+ test(); // uncomment to run test
idle(rcc, gpioa);
loop {
continue;
@@ -192,7 +201,9 @@ fn idle(rcc: &mut RCC, gpioa: &mut GPIOA) {
// alternatively to set the bit high we can
// read the value, or with PA5 (bit 5) and write back
- gpioa.ODR.write(gpioa.ODR.read() | (1 << 5));
+ // gpioa.ODR.write(gpioa.ODR.read() | (1 << 5));
+
+ gpioa.ODR.modify(5, 1, 1);
wait(10_000);
@@ -201,7 +212,9 @@ fn idle(rcc: &mut RCC, gpioa: &mut GPIOA) {
// alternatively to clear the bit we can
// read the value, mask out PA5 (bit 5) and write back
- gpioa.ODR.write(gpioa.ODR.read() & !(1 << 5));
+ // gpioa.ODR.write(gpioa.ODR.read() & !(1 << 5));
+ gpioa.ODR.modify(5, 1, 0);
+
wait(10_000);
}
}
--
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