bare5_2

examples/bare5.rs

@@ -9,16 +9,18 @@
 #![no_std]
 #![no_main]
 
-extern crate panic_halt;
+extern crate panic_semihosting;
 
 extern crate cortex_m;
 use cortex_m_rt::entry;
+use cortex_m_semihosting::{hprint, hprintln};
 
 // C like API...
 mod stm32f40x {
     #[allow(dead_code)]
     use core::{cell, ptr};
 
+    use cortex_m_semihosting::{hprint, hprintln};
     #[rustfmt::skip]
     mod address {
         pub const PERIPH_BASE: u32      = 0x40000000;
@@ -50,19 +52,31 @@ mod stm32f40x {
         }
     }
 
-    // modify (reads, modifies a field, and writes the volatile cell)
-    //
-    // parameters:
-    // offset (field offset)
-    // 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
-    //     }
-    // }
+    //modify (reads, modifies a field, and writes the volatile cell)
+    
+    //parameters:
+    //offset (field offset)
+    //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) {
+            unsafe{
+                let mut mask: u32 = 1;
+                for i in 0..width{
+                   mask = mask | 1 << i;
+                }
+                mask = mask << offset;
+                let vaoff = (value << offset);
+                let vaoffmask = vaoff & mask;
+                let readinvmask =  self.read() & !mask; 
+                let finalval = readinvmask |vaoffmask;
+                hprintln!("{:#b}",finalval);
+                self.write(finalval);
+            }
+        }
+    }
 
     #[repr(C)]
     #[allow(non_snake_case)]
@@ -140,28 +154,29 @@ 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);
-
-// if << is used, your code will panic in dev (debug), but not in release mode
-// t.modify(32, 3, 1);
-//}
+//simple test of Your `modify`
+fn test() {
+    let t:VolatileCell<u32> = unsafe {  core::mem::uninitialized() };
+    t.write(0);
+    assert!(t.read() == 0);
+    hprintln!("{:?}", 123).unwrap();
+    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);
+
+    //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 +184,7 @@ 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;