New 07 Registers

Modified to run using `stm32f3-discovery` instead of `f3` and updated
the `.md` files appropriately.

Author: winksaville

src/07-registers/Cargo.toml

@@ -1,8 +1,11 @@
 [package]
-authors = ["Jorge Aparicio <jorge@japaric.io>"]
+authors = [
+    "Jorge Aparicio <jorge@japaric.io>",
+    "Wink Saville <wink@saville.com",
+]
 edition = "2018"
 name = "registers"
-version = "0.1.0"
+version = "0.2.0"
 
 [dependencies]
 aux7 = { path = "auxiliary" }

src/07-registers/auxiliary/Cargo.toml

@@ -1,14 +1,19 @@
 [package]
-authors = ["Jorge Aparicio <jorge@japaric.io>"]
+authors = [
+    "Jorge Aparicio <jorge@japaric.io>",
+    "Wink Saville <wink@saville.com",
+]
 edition = "2018"
 name = "aux7"
-version = "0.1.0"
+version = "0.2.0"
 
 [dependencies]
-cortex-m = "0.6.3"
-cortex-m-rt = "0.6.3"
-panic-itm = "0.4.0"
+cortex-m = "0.6.4"
+cortex-m-rt = "0.6.13"
+stm32f3-discovery = "0.6.0"
+panic-halt = "0.2.0"
+panic-itm = "0.4.2"
 
-[dependencies.f3]
-features = ["rt"]
-version = "0.6.1"
+[dependencies.stm32f3]
+version = "0.12.1"
+features = ["stm32f303", "rt"]

src/07-registers/auxiliary/src/lib.rs

@@ -3,28 +3,38 @@
 #![deny(warnings)]
 #![no_std]
 
-#[allow(unused_extern_crates)] // NOTE(allow) bug rust-lang/rust#53964
 extern crate panic_itm; // panic handler
 
 pub use cortex_m::{asm::bkpt, iprint, iprintln, peripheral::ITM};
 pub use cortex_m_rt::entry;
-use f3::{
-    hal::{
-        prelude::*,
-        stm32f30x::gpioc,
-        stm32f30x::{self, GPIOE},
-    },
-    led::Leds,
-};
 
-#[inline(never)]
-pub fn init() -> (ITM, &'static gpioc::RegisterBlock) {
-    let cp = cortex_m::Peripherals::take().unwrap();
-    let dp = stm32f30x::Peripherals::take().unwrap();
+pub use stm32f3::stm32f303::{self, gpioc::RegisterBlock};
+pub use stm32f3_discovery::stm32f3xx_hal::pac::GPIOE;
+pub use stm32f3_discovery::{leds::Leds, stm32f3xx_hal};
+
+use stm32f3xx_hal::prelude::*;
+pub use stm32f3xx_hal::stm32;
 
-    let mut rcc = dp.RCC.constrain();
+#[inline(never)]
+pub fn init() -> (ITM, &'static RegisterBlock) {
+    let device_periphs = stm32::Peripherals::take().unwrap();
+    let mut reset_and_clock_control = device_periphs.RCC.constrain();
 
-    Leds::new(dp.GPIOE.split(&mut rcc.ahb));
+    // initialize user leds
+    let mut gpioe = device_periphs.GPIOE.split(&mut reset_and_clock_control.ahb);
+    let _leds = Leds::new(
+        gpioe.pe8,
+        gpioe.pe9,
+        gpioe.pe10,
+        gpioe.pe11,
+        gpioe.pe12,
+        gpioe.pe13,
+        gpioe.pe14,
+        gpioe.pe15,
+        &mut gpioe.moder,
+        &mut gpioe.otyper,
+    );
 
-    (cp.ITM, unsafe { &*GPIOE::ptr() })
+    let core_periphs = cortex_m::Peripherals::take().unwrap();
+    (core_periphs.ITM, unsafe { &*stm32f303::GPIOE::ptr() })
 }

src/07-registers/bad-address.md

@@ -29,16 +29,20 @@ Invalid in the sense that there's no register at this address.
 Now, let's try it.
 
 ``` console
+ cargo run
 $ cargo run
-Breakpoint 3, main () at src/07-registers/src/main.rs:9
-9           aux7::init();
+(..)
+Breakpoint 1, registers::__cortex_m_rt_main_trampoline () at src/07-registers/src/main.rs:9
+9       #[entry]
 
 (gdb) continue
 Continuing.
 
-Breakpoint 2, cortex_m_rt::HardFault_ (ef=0x10001fb0)
-    at $REGISTRY/cortex-m-rt-0.6.13/src/lib.rs:560
+Breakpoint 3, cortex_m_rt::HardFault_ (ef=0x20009fb0)
+    at /home/wink/.cargo/registry/src/github.com-1ecc6299db9ec823/cortex-m-rt-0.6.13/src/lib.rs:560
 560         loop {
+
+(gdb)
 ```
 
 We tried to do an invalid operation, reading memory that doesn't exist, so the processor raised an
@@ -77,13 +81,13 @@ We can get more information about the exception from the debugger. Let's see:
 (gdb) print/x *ef
 $1 = cortex_m_rt::ExceptionFrame {
   r0: 0x48001800,
-  r1: 0x48001800,
-  r2: 0xb,
-  r3: 0xc,
-  r12: 0xd,
-  lr: 0x800019f,
-  pc: 0x80028d6,
-  xpsr: 0x1000000
+  r1: 0x80036b0,
+  r2: 0x1,
+  r3: 0x80000000,
+  r12: 0xb,
+  lr: 0x800020d,
+  pc: 0x8001750,
+  xpsr: 0xa1000200
 }
 ```
 
@@ -93,25 +97,27 @@ disassemble the program around the bad instruction.
 
 ```
 (gdb) disassemble /m ef.pc
-Dump of assembler code for function core::ptr::read_volatile:
-471     /checkout/src/libcore/ptr.rs: No such file or directory.
-   0x080028ce <+0>:     sub     sp, #16
-   0x080028d0 <+2>:     mov     r1, r0
-   0x080028d2 <+4>:     str     r0, [sp, #8]
-
-472     in /checkout/src/libcore/ptr.rs
-   0x080028d4 <+6>:     ldr     r0, [sp, #8]
-   0x080028d6 <+8>:     ldr     r0, [r0, #0]
-   0x080028d8 <+10>:    str     r0, [sp, #12]
-   0x080028da <+12>:    ldr     r0, [sp, #12]
-   0x080028dc <+14>:    str     r1, [sp, #4]
-   0x080028de <+16>:    str     r0, [sp, #0]
-   0x080028e0 <+18>:    b.n     0x80028e2 <core::ptr::read_volatile+20>
-
-473     in /checkout/src/libcore/ptr.rs
-   0x080028e2 <+20>:    ldr     r0, [sp, #0]
-   0x080028e4 <+22>:    add     sp, #16
-   0x080028e6 <+24>:    bx      lr
+Dump of assembler code for function core::ptr::read_volatile<u32>:
+1046    pub unsafe fn read_volatile<T>(src: *const T) -> T {
+   0x0800174c <+0>:     sub     sp, #12
+   0x0800174e <+2>:     str     r0, [sp, #4]
+
+1047        if cfg!(debug_assertions) && !is_aligned_and_not_null(src) {
+1048            // Not panicking to keep codegen impact smaller.
+1049            abort();
+1050        }
+1051        // SAFETY: the caller must uphold the safety contract for `volatile_load`.
+1052        unsafe { intrinsics::volatile_load(src) }
+   0x08001750 <+4>:     ldr     r0, [r0, #0]
+   0x08001752 <+6>:     str     r0, [sp, #8]
+   0x08001754 <+8>:     ldr     r0, [sp, #8]
+   0x08001756 <+10>:    str     r0, [sp, #0]
+   0x08001758 <+12>:    b.n     0x800175a <core::ptr::read_volatile<u32>+14>
+
+1053    }
+   0x0800175a <+14>:    ldr     r0, [sp, #0]
+   0x0800175c <+16>:    add     sp, #12
+   0x0800175e <+18>:    bx      lr
 
 End of assembler dump.
 ```
@@ -126,16 +132,16 @@ when the exception was raised? Well, we already did! The `r0` field in the `ef`
 before is the value of `r0` register had when the exception was raised. Here it is again:
 
 ```
-(gdb) p/x *ef
+(gdb) print/x *ef
 $1 = cortex_m_rt::ExceptionFrame {
   r0: 0x48001800,
-  r1: 0x48001800,
-  r2: 0xb,
-  r3: 0xc,
-  r12: 0xd,
-  lr: 0x800019f,
-  pc: 0x80028d6,
-  xpsr: 0x1000000
+  r1: 0x80036b0,
+  r2: 0x1,
+  r3: 0x80000000,
+  r12: 0xb,
+  lr: 0x800020d,
+  pc: 0x8001750,
+  xpsr: 0xa1000200
 }
 ```
 

src/07-registers/openocd.gdb

@@ -1,10 +1,11 @@
 target remote :3333
 set print asm-demangle on
 set print pretty on
+set style sources off
 monitor tpiu config internal itm.txt uart off 8000000
 monitor itm port 0 on
 load
+break main
 break DefaultHandler
 break HardFault
-break main
 continue