dma.h

Wrapper functions for direct memory access hardware. [詳細]

#include "nds/ndstypes.h"

ソースコードを見る。

マクロ定義
#define	DMA0_SRC   (*(vuint32*)0x040000B0)
#define	DMA0_DEST   (*(vuint32*)0x040000B4)
#define	DMA0_CR   (*(vuint32*)0x040000B8)
#define	DMA1_SRC   (*(vuint32*)0x040000BC)
#define	DMA1_DEST   (*(vuint32*)0x040000C0)
#define	DMA1_CR   (*(vuint32*)0x040000C4)
#define	DMA2_SRC   (*(vuint32*)0x040000C8)
#define	DMA2_DEST   (*(vuint32*)0x040000CC)
#define	DMA2_CR   (*(vuint32*)0x040000D0)
#define	DMA3_SRC   (*(vuint32*)0x040000D4)
#define	DMA3_DEST   (*(vuint32*)0x040000D8)
#define	DMA3_CR   (*(vuint32*)0x040000DC)
#define	DMA_SRC(n)   (*(vuint32*)(0x040000B0+(n*12)))
#define	DMA_DEST(n)   (*(vuint32*)(0x040000B4+(n*12)))
#define	DMA_CR(n)   (*(vuint32*)(0x040000B8+(n*12)))
#define	DMA_ENABLE   BIT(31)
#define	DMA_BUSY   BIT(31)
#define	DMA_IRQ_REQ   BIT(30)
#define	DMA_START_NOW   0
#define	DMA_START_CARD   (5<<27)
#define	DMA_16_BIT   0
#define	DMA_32_BIT   BIT(26)
#define	DMA_REPEAT   BIT(25)
#define	DMA_SRC_INC   (0)
#define	DMA_SRC_DEC   BIT(23)
#define	DMA_SRC_FIX   BIT(24)
#define	DMA_DST_INC   (0)
#define	DMA_DST_DEC   BIT(21)
#define	DMA_DST_FIX   BIT(22)
#define	DMA_DST_RESET   (3<<21)
#define	DMA_COPY_WORDS   (DMA_ENABLE | DMA_32_BIT | DMA_START_NOW)
#define	DMA_COPY_HALFWORDS   (DMA_ENABLE | DMA_16_BIT | DMA_START_NOW)
#define	DMA_FIFO   (DMA_ENABLE | DMA_32_BIT | DMA_DST_FIX | DMA_START_FIFO)
関数
void	dmaCopyWords (uint8 channel, const void *src, void *dest, uint32 size)
	copies from source to destination on one of the 4 available channels in words
void	dmaCopyHalfWords (uint8 channel, const void *src, void *dest, uint32 size)
	copies from source to destination on one of the 4 available channels in half words
void	dmaCopy (const void *source, void *dest, uint32 size)
	copies from source to destination using channel 3 of DMA available channels in half words
void	dmaCopyWordsAsynch (uint8 channel, const void *src, void *dest, uint32 size)
	copies from source to destination on one of the 4 available channels in half words. This function returns immediately after starting the transfer.
void	dmaCopyHalfWordsAsynch (uint8 channel, const void *src, void *dest, uint32 size)
	copies from source to destination on one of the 4 available channels in half words. This function returns immediately after starting the transfer.
void	dmaCopyAsynch (const void *source, void *dest, uint32 size)
	copies from source to destination using channel 3 of DMA available channels in half words. This function returns immediately after starting the transfer.
void	dmaFillWords (u32 value, void *dest, uint32 size)
	fills the source with the supplied value using DMA channel 3
void	dmaFillHalfWords (u16 value, void *dest, uint32 size)
	fills the source with the supplied value using DMA channel 3
int	dmaBusy (uint8 channel)
	determines if the specified channel is busy

---

説明

Wrapper functions for direct memory access hardware.

The DS has 4 hardware direct memory access devices per CPU which can be used to transfer or fill chunks of memeory without CPU intervention. Utilizing DMA is generaly faster than CPU copies (memcpy, swiCopy, for loops, etc..).

DMA has no access to data caches on the DS and as such will give unexpected results when DMAing data from main memory. The cache must be flushed as follows when using DMA to ensure proper opertion on the arm9:

DC_FlushRange(source, sizeof(dataToCopy));
dmaCopy(source, destination, sizeof(dataToCopy));

---

関数

static dmaBusy

(

uint8

channel

)

[inline]

determines if the specified channel is busy

引数:

channel

the dma channel to check (0 - 3).

戻り値:

non zero if busy, 0 if channel is free

static void dmaCopy	(	const void *	source,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination using channel 3 of DMA available channels in half words

引数:

	source	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest half word (2 bytes)

例:

audio/micrecord/source/micrecord.c, Graphics/Backgrounds/all_in_one/source/advanced.cpp, Graphics/Backgrounds/all_in_one/source/basic.cpp, Graphics/Backgrounds/all_in_one/source/handmade.cpp, Graphics/Backgrounds/all_in_one/source/scrolling.cpp, と Graphics/Sprites/animate_simple/source/template.c.

static void dmaCopyAsynch	(	const void *	src,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination using channel 3 of DMA available channels in half words. This function returns immediately after starting the transfer.

引数:

	src	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest half word (2 bytes)

static void dmaCopyHalfWords	(	uint8	channel,
		const void *	src,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination on one of the 4 available channels in half words

引数:

	channel	the dma channel to use (0 - 3).
	src	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest half word (2 bytes)

static void dmaCopyHalfWordsAsynch	(	uint8	channel,
		const void *	src,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination on one of the 4 available channels in half words. This function returns immediately after starting the transfer.

引数:

	channel	the dma channel to use (0 - 3).
	src	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest half word (2 bytes)

static void dmaCopyWords	(	uint8	channel,
		const void *	src,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination on one of the 4 available channels in words

引数:

	channel	the dma channel to use (0 - 3).
	src	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest word (4 bytes)

static void dmaCopyWordsAsynch	(	uint8	channel,
		const void *	src,
		void *	dest,
		uint32	size
	)			[inline]

copies from source to destination on one of the 4 available channels in half words. This function returns immediately after starting the transfer.

引数:

	channel	the dma channel to use (0 - 3).
	src	the source to copy from
	dest	the destination to copy to
	size	the size in bytes of the data to copy. Will be truncated to the nearest word (4 bytes)

static void dmaFillHalfWords	(	u16	value,
		void *	dest,
		uint32	size
	)			[inline]

fills the source with the supplied value using DMA channel 3

引数:

	value	the 16 byte value to fill memory with
	dest	the destination to copy to
	size	the size in bytes of the area to fill. Will be truncated to the nearest half word (2 bytes)

例:

Graphics/Sprites/bitmap_sprites/source/main.cpp.

static void dmaFillWords	(	u32	value,
		void *	dest,
		uint32	size
	)			[inline]

fills the source with the supplied value using DMA channel 3

引数:

	value	the 32 byte value to fill memory with
	dest	the destination to copy to
	size	the size in bytes of the area to fill. Will be truncated to the nearest word (4 bytes)