Documentation fixup arm9/image.h, nds/tmers.h (devkitPro#17)

* Better math preamble.

* Corrected 4 spelling errors in arm9/video.h preamble.

* Clarify arm9/image.h documentation.

* Corrected various errors in timers.h documentation

- Mhz => MHz, hz is not a real unit
- Added spaces to verious words
- Interupt => Interrupt

* Applied pull request comments

devkitPro#17

include/nds/arm9/image.h

@@ -26,10 +26,10 @@
 	\brief An image abstraction for working with image data.
 
 <div class="fileHeader">
-Image data pointers must be allocated using malloc as the conversion
-rutiens will free the pointers and allocate new data.  As such any loader
-implemented utilizing this structure must use malloc() to allocate the image
-pointer data.
+Image data buffers must be allocated using malloc() rather than pointing to stack data, as the conversion
+routines will free() the argument's image buffer and allocate a new block for the replacement data.
+As such, any loader implemented utilizing this structure must use malloc() to allocate the image
+buffer.
 </div>
 */
 
@@ -70,17 +70,17 @@ typedef struct sImage
 extern "C" {
 #endif
 
-/*! \brief Converts a 24 bit image to 16 bit
+/*! \brief Destructively converts a 24-bit image to 16-bit
 	\param img a pointer to image to manipulate
 */
 void image24to16(sImage* img);
 
-/*! \brief Converts an 8 bit image to 16 bit setting the alpha bit
+/*! \brief Destructively converts an 8-bit image to 16 bit setting the alpha bit
 	\param img a pointer to image to manipulate
 */
 void image8to16(sImage* img);
 
-/*! \brief Converts an 8 bit image to 16 bit with alpha bit cleared for the supplied palette index
+/*! \brief Destructively converts an 8-bit image to 16-bit with alpha bit cleared for the supplied palette index
 	\param img a pointer to image to manipulate
 	\param transparentColor Color indexes equal to this value will have the alpha bit clear
 */
@@ -91,7 +91,7 @@ void image8to16trans(sImage* img, u8 transparentColor);
 */
 void imageDestroy(sImage* img);
 
-/*! \brief Tiles 8 bit image data into a sequence of 8x8 tiles
+/*! \brief Tiles 8-bit image data into a sequence of 8x8 tiles
 	\param img a pointer to image to manipulate
 */
 void imageTileData(sImage* img);

include/nds/timers.h

@@ -73,8 +73,8 @@ extern "C" {
 /*!	\see TIMER_CR(n)
 	\see TIMER_FREQ(n)
 
-	%TIMER_DATA(n) when set will latch that value into the counter.  Everytime the
-	counter rolls over %TIMER_DATA(0) will return to the latched value.  This allows
+	%TIMER_DATA(n) when set will latch that value into the counter.  Every time the
+	counter rolls over, %TIMER_DATA(0) will return to the latched value.  This allows
 	you to control the frequency of the timer using the following formula:\n
 		%TIMER_DATA(x) = -(BUS_CLOCK/(freq * divider));
 
@@ -100,7 +100,7 @@ extern "C" {
 
 //!	Enables the timer.
 #define TIMER_ENABLE    (1<<7)
-//!	Causes the timer to request an Interupt on overflow.
+//!	Causes the timer to request an Interrupt on overflow.
 #define TIMER_IRQ_REQ   (1<<6)
 //!	When set will cause the timer to count when the timer below overflows (unavailable for timer 0).
 #define TIMER_CASCADE   (1<<2)
@@ -116,13 +116,13 @@ typedef enum {
 
 
 //use the ClockDivider enum.
-//	Causes the timer to count at 33.514 Mhz.
+//	Causes the timer to count at 33.514 MHz.
 #define TIMER_DIV_1     (0)
-//	Causes the timer to count at (33.514 / 64) Mhz.
+//	Causes the timer to count at (33.514 / 64) MHz.
 #define TIMER_DIV_64    (1)
-//	Causes the timer to count at (33.514 / 256) Mhz.
+//	Causes the timer to count at (33.514 / 256) MHz.
 #define TIMER_DIV_256   (2)
-//	Causes the timer to count at (33.514 / 1024) Mhz.
+//	Causes the timer to count at (33.514 / 1024) MHz.
 #define TIMER_DIV_1024  (3)
 
 
@@ -202,18 +202,18 @@ typedef enum {
 
 
 /*!	\brief start a hardware timer.
-	Callback is tied directly to interupt table and called directly resulting in less latency than the attached timer.
+	Callback is tied directly to interrupt table and called directly, resulting in less latency than the attached timer.
 	\param timer 	The hardware timer to use (0 - 3).
-	\param divider 	The timer channel clock divider (clock will tick at 33.513982 Mhz / divider)
+	\param divider 	The timer channel clock divider (clock will tick at 33.513982 MHz / divider)
 	\param ticks	The number of ticks which must elapse before the timer overflows
-	\param callback The callback to be called when the timer expires (if null no irq will be generated by the timer)
+	\param callback The callback to be called when the timer expires (if null, no IRQ will be generated by the timer)
 */
 void timerStart(int timer, ClockDivider divider, u16 ticks, VoidFn callback);
 
 
 /*!	\brief returns the ticks elapsed since the last call to timerElapsed().
 	\param timer The hardware timer to use (0 - 3).
-	\return The number of ticks which have elapsed since the last callto timerElapsed().
+	\return The number of ticks which have elapsed since the last call to timerElapsed().
 */
 u16 timerElapsed(int timer);
 
@@ -230,7 +230,7 @@ u16 timerTick(int timer) {
 
 /*!	\brief pauses the specified timer.
 	\param timer The hardware timer to use (0 - 3).
-	\return The number of ticks which have elapsed since the last callto timerElapsed().
+	\return The number of ticks which have elapsed since the last call to timerElapsed().
 */
 u16 timerPause(int timer);
 
@@ -246,7 +246,7 @@ void timerUnpause(int timer) {
 
 /*!	\brief Stops the specified timer.
 	\param timer The hardware timer to use (0 - 3).
-	\return The number of ticks which have elapsed since the last callto timerElapsed().
+	\return The number of ticks which have elapsed since the last call to timerElapsed().
 */
 u16 timerStop(int timer);