diff --git a/lib/stm32/nvic.c b/lib/stm32/nvic.c
index 0b6f845b..502d212c 100644
--- a/lib/stm32/nvic.c
+++ b/lib/stm32/nvic.c
@@ -2,6 +2,7 @@
  * This file is part of the libopencm3 project.
  *
  * Copyright (C) 2010 Thomas Otto <tommi@viadmin.org>
+ * Copyright (C) 2012 Fergus Noble <fergusnoble@gmail.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,75 +22,37 @@
 
 void nvic_enable_irq(u8 irqn)
 {
-	if (irqn < 32)
-		NVIC_ISER(0) |= (1 << irqn);
-	if ((irqn >= 32) & (irqn < 64))
-		NVIC_ISER(1) |= (1 << (irqn - 32));
-	if ((irqn >= 64) & (irqn < 68))
-		NVIC_ISER(2) |= (1 << (irqn - 64));
+  NVIC_ISER(irqn / 32) = (1 << (irqn % 32));
 }
 
 void nvic_disable_irq(u8 irqn)
 {
-	if (irqn < 32)
-		NVIC_ICER(0) |= (1 << irqn);
-	if ((irqn >= 32) & (irqn < 64))
-		NVIC_ICER(1) |= (1 << (irqn - 32));
-	if ((irqn >= 64) & (irqn < 68))
-		NVIC_ICER(2) |= (1 << (irqn - 64));
+  NVIC_ICER(irqn / 32) = (1 << (irqn % 32));
 }
 
 u8 nvic_get_pending_irq(u8 irqn)
 {
-	if (irqn < 32)
-		return (NVIC_ISPR(0) & (1 << irqn));
-	if ((irqn >= 32) & (irqn < 64))
-		return (NVIC_ISPR(1) & (1 << (irqn - 32)));
-	if ((irqn >= 64) & (irqn < 68))
-		return (NVIC_ISPR(2) & (1 << (irqn - 64)));
-	return 0;
+  return NVIC_ISPR(irqn / 32) & (1 << (irqn % 32)) ? 1:0;
 }
 
 void nvic_set_pending_irq(u8 irqn)
 {
-	if (irqn < 32)
-		NVIC_ISPR(0) |= (1 << irqn);
-	if ((irqn >= 32) & (irqn < 64))
-		NVIC_ISPR(1) |= (1 << (irqn - 32));
-	if ((irqn >= 64) & (irqn < 68))
-		NVIC_ISPR(2) |= (1 << (irqn - 64));
+  NVIC_ISPR(irqn / 32) = (1 << (irqn % 32));
 }
 
 void nvic_clear_pending_irq(u8 irqn)
 {
-	if (irqn < 32)
-		NVIC_ICPR(0) |= (1 << irqn);
-	if ((irqn >= 32) & (irqn < 64))
-		NVIC_ICPR(1) |= (1 << (irqn - 32));
-	if ((irqn >= 64) & (irqn < 68))
-		NVIC_ICPR(2) |= (1 << (irqn - 64));
+  NVIC_ICPR(irqn / 32) = (1 << (irqn % 32));
 }
 
 u8 nvic_get_active_irq(u8 irqn)
 {
-	if (irqn < 32)
-		return (NVIC_IABR(0) & (1 << irqn));
-	if ((irqn >= 32) & (irqn < 64))
-		return (NVIC_IABR(1) & (1 << (irqn - 32)));
-	if ((irqn >= 64) & (irqn < 68))
-		return (NVIC_IABR(2) & (1 << (irqn - 64)));
-	return 0;
+  return NVIC_IABR(irqn / 32) & (1 << (irqn % 32)) ? 1:0;
 }
 
 u8 nvic_get_irq_enabled(u8 irqn)
 {
-	if (irqn < 32)
-		return (NVIC_ISER(0) & (1 << irqn));
-	if ((irqn >= 32) & (irqn < 64))
-		return (NVIC_ISER(1) & (1 << (irqn - 32)));
-	if ((irqn >= 64) & (irqn < 68))
-		return (NVIC_ISER(2) & (1 << (irqn - 64)));
-	return 0;
+  return NVIC_ISER(irqn / 32) & (1 << (irqn % 32)) ? 1:0;
 }
 
 void nvic_set_priority(u8 irqn, u8 priority)