1 files changed, 57 insertions, 1 deletions
diff --git a/02-usart/include/core/irq.h b/02-usart/include/core/irq.h
index ae1126d..f2fe8d9 100644
--- a/02-usart/include/core/irq.h
+++ b/02-usart/include/core/irq.h
@@ -16,6 +16,42 @@ typedef enum {
 #undef IRQ_RESERVED
 } interrupt_t;
 
+/* Defines a set of interrupts so they may be enabled all at once. */
+typedef struct {
+  uint32_t sysirqs; /* System iterrupts. */
+  uint32_t irqs[8];
+} interrupt_set_t;
+
+inline static void interrupt_set_add(
+    interrupt_set_t* interrupt_set, interrupt_t interrupt)
+{
+  if (interrupt < 16) {
+    interrupt_set->sysirqs |= 1 << interrupt;
+    return;
+  }
+
+  interrupt -= 16;
+  int loc = interrupt / 32;
+  int off = interrupt % 32;
+
+  interrupt_set->irqs[loc] |= 1 << off;
+}
+
+inline static void interrupt_set_remove(
+    interrupt_set_t* interrupt_set, interrupt_t interrupt)
+{
+  if (interrupt < 16) {
+    interrupt_set->sysirqs &= ~(1 << interrupt);
+    return;
+  }
+
+  interrupt -= 16;
+  int loc = interrupt / 32;
+  int off = interrupt % 32;
+
+  interrupt_set->irqs[loc] &= ~(1 << off);
+}
+
 /*
  * The interrupt service routines. These link in the function `main` as the
  * main function.
@@ -28,6 +64,26 @@ extern const void* vectors[];
  */
 void unhandled_isr(uint8_t val);
 
-void isr_simple_pin_on();
+#define enable_interrupt(val) \
+  {interrupt_set_t itrset = { 0 }; \
+   interrupt_set_add(&itrset, val); \
+    enable_interrupts(&itrset);}
+
+#define disable_interrupt(val) \
+  {interrupt_set_t itrset = { 0 }; \
+   interrupt_set_add(&itrset, val); \
+    disable_interrupts(&itrset);}
+
+/*
+ * Enables the provided interrupt. Note that if the interrupt is one of the
+ * system interrupts (first 16) this function has no effect because those
+ * interrupts are always enabled.
+ */
+void enable_interrupts(interrupt_set_t* interrupts);
+
+/*
+ * Enables the provided interrupt 
+ */
+void disable_interrupts(interrupt_set_t* interrupts);
 
 #endif /* CORE_IRQ_H_ */