dsp.h File Reference

SCU DSP: the third processor of the Saturn (about 14 MHz, one 32 x 32 bits multiply and accumulate per cycle). More...

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Macros
#define	JO_DSP_BANK_SIZE
	Words of a data RAM bank.
#define	JO_DSP_PROGRAM_SIZE
	Words of the program RAM.
#define	JO_DSP_PPAF
	Program control port (PPAF).
#define	JO_DSP_PPD
	Program RAM data port.
#define	JO_DSP_PDA
	Data RAM address port.
#define	JO_DSP_PDD
	Data RAM data port.
#define	JO_DSP_PPAF_EXECUTE
	PPAF: execute (write: start, read: running).
#define	JO_DSP_PPAF_LOAD
	PPAF: program counter load (the low 8 bits).
#define	JO_DSP_PPAF_DMA
	PPAF: a DMA of the DSP is in progress.

Functions
void	jo_dsp_load_program (const unsigned int *const program, const unsigned int count)
	Stop the DSP and load a program.
void	jo_dsp_write_data (const unsigned int bank, const unsigned int address, const unsigned int *const data, const unsigned int count)
	Write the data RAM (the DSP must be stopped).
void	jo_dsp_read_data (const unsigned int bank, const unsigned int address, unsigned int *const data, const unsigned int count)
	Read the data RAM (the DSP must be stopped).
static __jo_force_inline void	jo_dsp_start (const unsigned int pc)
	Start the program loaded by jo_dsp_load_program().
static __jo_force_inline bool	jo_dsp_is_running (void)
	Check if the DSP is running.
static __jo_force_inline void	jo_dsp_wait (void)
	Wait for the end of the program started by jo_dsp_start().

Detailed Description

SCU DSP: the third processor of the Saturn (about 14 MHz, one 32 x 32 bits multiply and accumulate per cycle).

Author

Johannes Fetz

Remarks

The DSP has 256 instructions of program RAM and 4 banks of 64 words of data RAM. It reads and writes the high work RAM and the B-bus by DMA (not the low work RAM). It has no division

Programs are written in DSP assembler and converted to a C array by Compiler/COMMON/scudsp_asm.py

The 3D module can use the DSP to transform the vertices (see jo_3d_enable_dsp())

Warning

The data RAM and the program RAM can only be accessed by the CPU when the DSP is stopped

Macro Definition Documentation

JO_DSP_BANK_SIZE

#define JO_DSP_BANK_SIZE

Words of a data RAM bank.

JO_DSP_PDA

#define JO_DSP_PDA

Data RAM address port.

JO_DSP_PDD

#define JO_DSP_PDD

Data RAM data port.

JO_DSP_PPAF

#define JO_DSP_PPAF

Program control port (PPAF).

JO_DSP_PPAF_DMA

#define JO_DSP_PPAF_DMA

PPAF: a DMA of the DSP is in progress.

JO_DSP_PPAF_EXECUTE

#define JO_DSP_PPAF_EXECUTE

PPAF: execute (write: start, read: running).

JO_DSP_PPAF_LOAD

#define JO_DSP_PPAF_LOAD

PPAF: program counter load (the low 8 bits).

JO_DSP_PPD

#define JO_DSP_PPD

Program RAM data port.

JO_DSP_PROGRAM_SIZE

#define JO_DSP_PROGRAM_SIZE

Words of the program RAM.

Function Documentation

jo_dsp_is_running()

__jo_force_inline bool jo_dsp_is_running ( void )

static

Check if the DSP is running.

Returns

true until the END instruction (and the end of the last DMA of the DSP)

jo_dsp_load_program()

void jo_dsp_load_program	(	const unsigned int *const	program,
		const unsigned int	count )

Stop the DSP and load a program.

Parameters

program	Instructions
count	Instruction count (256 at most)

jo_dsp_read_data()

void jo_dsp_read_data	(	const unsigned int	bank,
		const unsigned int	address,
		unsigned int *const	data,
		const unsigned int	count )

Read the data RAM (the DSP must be stopped).

Parameters

bank	Bank (0 to 3)
address	First word (0 to 63)
data	Words (output)
count	Word count

jo_dsp_start()

__jo_force_inline void jo_dsp_start ( const unsigned int pc )

static

Start the program loaded by jo_dsp_load_program().

Parameters

pc	First instruction

Remarks

The DSP runs until its END instruction, the CPU keeps working (see jo_dsp_is_running())

jo_dsp_wait()

__jo_force_inline void jo_dsp_wait ( void )

static

Wait for the end of the program started by jo_dsp_start().

jo_dsp_write_data()

void jo_dsp_write_data	(	const unsigned int	bank,
		const unsigned int	address,
		const unsigned int *const	data,
		const unsigned int	count )

Write the data RAM (the DSP must be stopped).

Parameters

bank	Bank (0 to 3)
address	First word (0 to 63)
data	Words
count	Word count