Nintendo DS BIOS functions. More...

#include <nds/ndstypes.h>

Data Structures
struct	DecompressionStream
	A struct that contains callback function pointers used by the decompression functions. More...

struct	UnpackStruct
	A struct and struct pointer with information about unpacking data. More...

Macros
#define	BIOS_UNPACK_OFFSET_ADD_ALWAYS (1u << 31)
	For TUnpackStruct.dataOffset, this flag signals that all destination writes, zero or non-zero, should be offset.

#define	BIOS_UNPACK_OFFSET_ADD_NON_ZERO (0u << 31)
	For TUnpackStruct.dataOffset, this flag signals that only non-zero destination writes should be offset.

#define	COPY_MODE_COPY (0)
	copy a range of memory to another piece of memory

#define	COPY_MODE_FILL BIT(24)
	Fill a piece of memory with a value.

#define	COPY_MODE_HWORD (0)
	Copy in chunks of halfword size.

#define	COPY_MODE_WORD BIT(26)
	Copy in chunks of word size.

Typedefs
typedef u8(*	getByteCallback) (u8 *source)
	Should return a raw byte of the stream.

typedef u16(*	getHalfWordCallback) (u16 *source)
	Should return a raw halfword of the stream.

typedef int(*	getHeaderCallback) (u8 source, u16 dest, u32 arg)
	Should return the header of a compressed stream of bytes.

typedef int(*	getResultCallback) (u8 *source)
	Should verify the result after data got decompressed.

typedef u32(*	getWordCallback) (u32 *source)
	Should return a raw word of the stream.

typedef struct DecompressionStream	TDecompressionStream
	A struct that contains callback function pointers used by the decompression functions.

typedef struct UnpackStruct	TUnpackStruct
	A struct and struct pointer with information about unpacking data.

Functions
static void	swiChangeSoundBias (int enabled, int delay)
	Increments or decrements the sound bias once per delay.

static void	swiCopy (const void source, void dest, int flags)
	Copies or fills some memory.

static uint16_t	swiCRC16 (uint16_t crc, const void *data, uint32_t size)
	Calculates a CRC-16 checksum using the following configuration:

static void	swiDecodeDelta16 (const void source, void destination)
	Decodes a stream of bytes based on the difference of the bytes.

static void	swiDecodeDelta8 (const void source, void destination)
	Decodes a stream of bytes based on the difference of the bytes.

static int	swiDecompressHuffman (const void source, void destination, uint32_t toGetSize, TDecompressionStream *stream)
	Decompresses Huffman compressed data.

int	swiDecompressLZSSVram (const void source, void destination, uint32_t toGetSize, TDecompressionStream *stream)
	Decompresses LZSS compressed data vram safe.

static void	swiDecompressLZSSWram (const void source, void destination)
	Decompresses LZSS compressed data.

static int	swiDecompressRLEVram (const void source, void destination, uint32_t toGetSize, TDecompressionStream *stream)
	Decompresses RLE compressed data vram safe.

static void	swiDecompressRLEWram (const void source, void destination)
	Decompresses RLE compressed data.

static void	swiDelay (uint32_t duration)
	Delays the code.

static int	swiDivide (int numerator, int divisor)
	Divides 2 numbers.

static void	swiDivMod (int numerator, int divisor, int result, int remainder)
	Divides 2 numbers and stores both the result and the remainder.

static void	swiFastCopy (const void source, void dest, int flags)
	Copies or fills some memory.

static uint16_t	swiGetPitchTable (int index)
	Returns an entry in the pitch table.

static uint16_t	swiGetSineTable (int index)
	Returns an entry in the sine table.

static uint8_t	swiGetVolumeTable (int index)
	Returns an entry in the volume table.

static void	swiHalt (void)
	Halts the CPU until an interupt occures.

static int	swiIsDebugger (void)
	Returns 1 if running on a Nintendo hardware debugger.

static int	swiRemainder (int numerator, int divisor)
	Calculate the remainder of an division.

void	swiSetHaltCR (uint32_t data)
	Writes a word of the data to 0x04000300:32.

void	swiSetHaltCR (uint8_t data)
	Writes a byte of the data to 0x04000301:8.

static void	swiSleep (void)
	Halts the CPU and most of the hardware untill an interupt occures.

void	swiSoftReset (void)
	Resets the CPU that called this function.

static int	swiSqrt (int value)
	Calculates the square root.

void	swiSwitchToGBAMode (void)
	Switches the DS to GBA mode.

static void	swiUnpackBits (const void source, void destination, TUnpackStruct *params)
	Unpack data stored in multiple elements in a byte to a larger space.

static void	swiWaitForIRQ (void)
	Wait for any interrupt.

Detailed Description

Nintendo DS BIOS functions.

See gbatek for more information.

Typedef Documentation

◆ getByteCallback

typedef u8(* getByteCallback) (u8 *source)

Should return a raw byte of the stream.

Parameters

source A pointer to the byte.

Returns: A byte.

◆ getHalfWordCallback

typedef u16(* getHalfWordCallback) (u16 *source)

Should return a raw halfword of the stream.

Parameters

source A pointer to the halfword.

Returns: A halfword.

◆ getHeaderCallback

typedef int(* getHeaderCallback) (u8 *source, u16 *dest, u32 arg)

Should return the header of a compressed stream of bytes.

The result is a word, with the size of decompressed data in bits 8 - 31, and bits 0 - 7 are ignored. This value is also returned by the bios function, unless getResult is non-NULL and returns a negative value. This useally returns the 4 bytes that source points to.

Parameters

source	A pointer to the compressed data.
dest	A pointer to the space where the decompressed data should be copied to.
arg	A callback value that gets passed to the bios function.

Returns: The header of the compressed data containing the length of the data and the compression type.

◆ getResultCallback

typedef int(* getResultCallback) (u8 *source)

Should verify the result after data got decompressed.

getResultCallback is used to provide a result for the bios function, given the source pointer after all data has been read (or if getSize < 0). Its value is only returned if negative, otherwise the typical result is used, so it is likely some sort of error-checking procedure.

Parameters

source The current source address.

Returns: 0 if it went right, or a negative number if something went wrong. The value will be returned from BIOS function if value is negative.

◆ getWordCallback

typedef u32(* getWordCallback) (u32 *source)

Should return a raw word of the stream.

Parameters

source A pointer to the word.

Returns: A word.

Function Documentation

◆ swiChangeSoundBias()

static void swiChangeSoundBias	(	int	enabled,
		int	delay
	)

inlinestatic

Increments or decrements the sound bias once per delay.

Parameters

enabled	Set to 0 to decrement it until it reaches 0x000, set to 1 to increment it until it reaches 0x200.
delay	Is in the same units of time as swiDelay.

Note: ARM7 exclusive.

◆ swiCopy()

static void swiCopy	(	const void *	source,
		void *	dest,
		int	flags
	)

inlinestatic

Copies or fills some memory.

Parameters

source	Pointer to transfer source or pointer to value to fill the memory with.
dest	Pointer to transfer destination.
flags	bits(0-20): size of data to copy/fill in words, or'd with the copy mode size (word or halfword) and type (copy or fill).

◆ swiCRC16()

static uint16_t swiCRC16	(	uint16_t	crc,
		const void *	data,
		uint32_t	size
	)

inlinestatic

Calculates a CRC-16 checksum using the following configuration:

Input reflected: Yes
Result reflected: Yes
Polynomial: 0x8005

Parameters

crc	Initial CRC-16 value.
data	Pointer to data (processed nibble by nibble)
size	Size in bytes.

Returns: The CRC-16 value after the data has been processed.

◆ swiDecodeDelta16()

static void swiDecodeDelta16	(	const void *	source,
		void *	destination
	)

inlinestatic

Decodes a stream of bytes based on the difference of the bytes.

Parameters

source	Pointer to a header word, followed by encoded data. word(31..8) = size of data (in bytes). word(7..0) = ignored.
destination	Destination address.

Note: Writes data a halfword at a time.; ARM9 exclusive.

◆ swiDecodeDelta8()

static void swiDecodeDelta8	(	const void *	source,
		void *	destination
	)

inlinestatic

Decodes a stream of bytes based on the difference of the bytes.

Parameters

source	Pointer to a header word, followed by encoded data. word(31..8) = size of data (in bytes). word(7..0) = ignored.
destination	Destination address.

Note: Writes data a byte at a time.; ARM9 exclusive.

◆ swiDecompressHuffman()

static int swiDecompressHuffman	(	const void *	source,
		void *	destination,
		uint32_t	toGetSize,
		TDecompressionStream *	stream
	)

inlinestatic

Decompresses Huffman compressed data.

Parameters

source	Pointer to source data (always goes through the function pointers, so could just be an offset).
destination	Pointer to destination.
toGetSize	Callback value that is passed to getHeaderCallback function pointer.
stream	Pointer to struct with callback function pointers.

Returns: The length of the decompressed data, or a signed errorcode from the Open/Close functions.

See also: decompress.h

◆ swiDecompressLZSSVram()

int swiDecompressLZSSVram	(	const void *	source,
		void *	destination,
		uint32_t	toGetSize,
		TDecompressionStream *	stream
	)

Decompresses LZSS compressed data vram safe.

Parameters

source	Pointer to source data (always goes through the function pointers, so could just be an offset).
destination	Pointer to destination.
toGetSize	Callback value that is passed to getHeaderCallback function pointer.
stream	Pointer to struct with callback function pointers.

Returns: The length of the decompressed data, or a signed errorcode from the Open/Close functions.

Note: This doesn't actually use a software interrupt, it's a custom function implemented in libnds.; Writes data a halfword at a time.

See also: decompress.h

◆ swiDecompressLZSSWram()

static void swiDecompressLZSSWram	(	const void *	source,
		void *	destination
	)

inlinestatic

Decompresses LZSS compressed data.

Parameters

source	Pointer to a header word, followed by compressed data. bit 0-7 of header is ignored. bit 8-31 of header is size of uncompressed data in bytes.
destination	Destination address.

Note: Writes data a byte at a time.

See also: decompress.h

◆ swiDecompressRLEVram()

static int swiDecompressRLEVram	(	const void *	source,
		void *	destination,
		uint32_t	toGetSize,
		TDecompressionStream *	stream
	)

inlinestatic

Decompresses RLE compressed data vram safe.

Compressed data format:

bit(7): 0 = uncompressed, 1 = compressed.
bit(0-6) when uncompressed: run length - 1, followed by run_length bytes of true data.
bit(0-6) when compressed: run length - 3, followed by one byte of true data, to be repeated.

Parameters

source	Pointer to source data (always goes through the function pointers, so could just be an offset).
destination	Pointer to destination.
toGetSize	Callback value that is passed to getHeaderCallback function pointer.
stream	Pointer to struct with callback function pointers.

Returns: The length of the decompressed data, or a signed errorcode from the Open/Close functions.

Note: Writes data a halfword at a time.

See also: decompress.h

◆ swiDecompressRLEWram()

static void swiDecompressRLEWram	(	const void *	source,
		void *	destination
	)

inlinestatic

Decompresses RLE compressed data.

Compressed data format:

bit(7): 0= uncompressed, 1= compressed.
bit(0-6) when uncompressed: run length - 1, followed by run_length bytes of true data.
bit(0-6) when compressed: run length - 3, followed by one byte of true data, to be repeated.

Parameters

source	Pointer to a header word, followed by compressed data. bit 0-7 of header is ignored. bit 8-31 of header is size of uncompressed data in bytes.
destination	Destination address.

Note: Writes data a byte at a time.

See also: decompress.h

◆ swiDelay()

static void swiDelay ( uint32_t duration )

inlinestatic

Delays the code.

Delays for for a period "X + Y * duration" where X is the swi overhead and Y is a cycle of Thumb fetches in BIOS memory.

     loop:
       sub r0, #1
       bgt loop

Parameters

duration Length of delay.

Note: Duration should be 1 or more, a duration of 0 is a huge delay.

◆ swiDivide()

static int swiDivide	(	int	numerator,
		int	divisor
	)

inlinestatic

Divides 2 numbers.

Parameters

numerator	Signed integer to divide.
divisor	Signed integer to divide by.

Returns: Numerator / divisor

◆ swiDivMod()

static void swiDivMod	(	int	numerator,
		int	divisor,
		int *	result,
		int *	remainder
	)

inlinestatic

Divides 2 numbers and stores both the result and the remainder.

Parameters

numerator	Signed integer to divide.
divisor	Signed integer to divide by.
result	Pointer to integer set to numerator / divisor.
remainder	Pointer to integer set to numerator % divisor.

◆ swiFastCopy()

static void swiFastCopy	(	const void *	source,
		void *	dest,
		int	flags
	)

inlinestatic

Copies or fills some memory.

Can only copy in word chunks.

Parameters

source	Pointer to transfer source or pointer to value to fill the memory with.
dest	Pointer to transfer destination.
flags	bits(0-20): size of data to copy/fill in words, or'd with the type (copy or fill).

Note: Transfers more quickly than swiCopy, but has higher interrupt latency.

◆ swiGetPitchTable()

static uint16_t swiGetPitchTable ( int index )

inlinestatic

Returns an entry in the pitch table.

Parameters

index The index of the pitch table (0 - 767).

Returns: The entry.

Note: ARM7 exclusive.

◆ swiGetSineTable()

static uint16_t swiGetSineTable ( int index )

inlinestatic

Returns an entry in the sine table.

Parameters

index The index of the sine table (0 - 63).

Returns: The entry.

Note: ARM7 exclusive.

◆ swiGetVolumeTable()

static uint8_t swiGetVolumeTable ( int index )

inlinestatic

Returns an entry in the volume table.

Parameters

index The index of the volume table (0 - 723).

Returns: The entry.

Note: ARM7 exclusive.

◆ swiHalt()

static void swiHalt ( void )

inlinestatic

Halts the CPU until an interupt occures.

Note: ARM7 exclusive.

◆ swiIsDebugger()

static int swiIsDebugger ( void )

inlinestatic

Returns 1 if running on a Nintendo hardware debugger.

Warning: It only works in DS mode (not DSi mode), and with the cache disabled. It's recommended to use isHwDebugger() instead, which works in DSi mode too, and it doesn't require the cache to be disabled.

Returns: 1 if running on a debugger (8 MB of RAM instead of 4 MB), else 0.

◆ swiRemainder()

static int swiRemainder	(	int	numerator,
		int	divisor
	)

inlinestatic

Calculate the remainder of an division.

Parameters

numerator	Signed integer to divide
divisor	Signed integer to divide by

Returns: Numerator % divisor

◆ swiSetHaltCR() [1/2]

void swiSetHaltCR ( uint32_t data )

Writes a word of the data to 0x04000300:32.

Parameters

data	The word to write.

Note: This is on the ARM9, but works differently then the ARM7 function!

◆ swiSetHaltCR() [2/2]

void swiSetHaltCR ( uint8_t data )

Writes a byte of the data to 0x04000301:8.

Parameters

data	The byte to write.

Note: ARM7 exclusive.

◆ swiSleep()

static void swiSleep ( void )

inlinestatic

Halts the CPU and most of the hardware untill an interupt occures.

Note: ARM7 exclusive.

◆ swiSoftReset()

void swiSoftReset ( void )

Resets the CPU that called this function.

Note: This doesn't actually use a software interrupt, it's a custom function implemented in libnds.

◆ swiSqrt()

static int swiSqrt ( int value )

inlinestatic

Calculates the square root.

Parameters

value The value to calculate.

Returns: The square root of the value as an integer.

Note: Use fixed point math if you want more accuracy.

◆ swiSwitchToGBAMode()

void swiSwitchToGBAMode ( void )

Switches the DS to GBA mode.

Note: ARM7 exclusive.

◆ swiUnpackBits()

static void swiUnpackBits	(	const void *	source,
		void *	destination,
		TUnpackStruct *	params
	)

inlinestatic

Unpack data stored in multiple elements in a byte to a larger space.

i.e. 8 elements per byte (i.e. b/w font), into 1 element per byte.

Parameters

source	Source address.
destination	Destination address (word aligned).
params	Pointer to an UnpackStruct.

◆ swiWaitForIRQ()

static void swiWaitForIRQ ( void )

inlinestatic

Wait for any interrupt.

Note: ARM9 exclusive.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Typedef Documentation

◆ getByteCallback

◆ getHalfWordCallback

◆ getHeaderCallback

◆ getResultCallback

◆ getWordCallback

Function Documentation

◆ swiChangeSoundBias()

◆ swiCopy()

◆ swiCRC16()

◆ swiDecodeDelta16()

◆ swiDecodeDelta8()

◆ swiDecompressHuffman()

◆ swiDecompressLZSSVram()

◆ swiDecompressLZSSWram()

◆ swiDecompressRLEVram()

◆ swiDecompressRLEWram()

◆ swiDelay()

◆ swiDivide()

◆ swiDivMod()

◆ swiFastCopy()

◆ swiGetPitchTable()

◆ swiGetSineTable()

◆ swiGetVolumeTable()

◆ swiHalt()

◆ swiIsDebugger()

◆ swiRemainder()

◆ swiSetHaltCR() [1/2]

◆ swiSetHaltCR() [2/2]

◆ swiSleep()

◆ swiSoftReset()

◆ swiSqrt()

◆ swiSwitchToGBAMode()

◆ swiUnpackBits()

◆ swiWaitForIRQ()