Experimental Gpio.HEADmaster

This rapidly blinks the sysled on the stm32.

This shows the ability to manipulate memory mapped registers.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/hal/common.rs b/src/hal/common.rs
new file mode 100644
index 0000000..9b07c4e
--- /dev/null
+++ b/src/hal/common.rs
@@ -0,0 +1,25 @@
+/*
+ * Sets bits in the register pointed to by 'reg'.
+ *
+ * reg: raw pointer to the register to manipulate.
+ * mask: the bits to change in the register. The binary of mask should follow
+ *       the regex 0*1*0* (i.e. all the 1's should be contiguous).
+ * val: The value to write to the bits referenced by 'mask'
+ */
+pub fn regset(reg: *mut u32, mask: u32, val: u32) -> () {
+    unsafe {
+        reg.write_volatile((reg.read_volatile() & !mask) | (val << mask.trailing_zeros()));
+    }
+}
+
+/*
+ * Returns bits in the register pointed to by 'reg'.
+ *
+ * reg: raw pointer to the register to read
+ * mask: the bits to retrieve.
+ */
+pub fn regget(reg: *mut u32, mask: u32) -> u32 {
+    unsafe {
+        (reg.read_volatile() & mask) >> mask.trailing_zeros()
+    }
+}