sys.h File Reference

Entry point unit / Interrupt callback / System. More...

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Defines
#define	PROCESS_PALETTE_FADING   (1 << 0)
#define	PROCESS_BITMAP_TASK   (1 << 1)
#define	PROCESS_TILECACHE_TASK   (1 << 2)
#define	PROCESS_SPRITEENGINE_TASK   (1 << 3)
Functions
void	SYS_assertReset ()
	Assert reset.
void	SYS_reset ()
	Soft reset.
u16	SYS_getInterruptMaskLevel ()
	Return current interrupt mask level.
void	SYS_setInterruptMaskLevel (u16 value)
	Set interrupt mask level.
u16	SYS_getAndSetInterruptMaskLevel (u16 value)
	Set the interrupt mask level to given value and return previous level.
void	SYS_disableInts ()
	Disable interrupts (Vertical, Horizontal and External).
void	SYS_enableInts ()
	Reenable interrupts (Vertical, Horizontal and External).
void	SYS_setVIntCallback (_voidCallback *CB)
	Set Vertical interrupt callback method.
void	SYS_setHIntCallback (_voidCallback *CB)
	Set Horizontal interrupt callback method.
void	SYS_setExtIntCallback (_voidCallback *CB)
	Set External interrupt callback method.
u16	SYS_isInVIntCallback ()
	Return != 0 if we are in the V-Int callback method.
u16	SYS_isInHIntCallback ()
	Return != 0 if we are in the H-Int callback method.
u16	SYS_isInExtIntCallback ()
	Return != 0 if we are in the Ext-Int callback method.
u16	SYS_isInInterrupt ()
	Return != 0 if we are in an interrupt callback method (Vertical, Horizontal or External)
void	SYS_die (char *err)
	Die with the specified error message. Program execution is interrupted.
Variables
u32	vtimer
u32	htimer
_voidCallback *	busErrorCB
	Bus error interrupt callback.
_voidCallback *	addressErrorCB
	Address error interrupt callback.
_voidCallback *	illegalInstCB
	Illegal instruction exception callback.
_voidCallback *	zeroDivideCB
	Division by zero exception callback.
_voidCallback *	chkInstCB
	CHK instruction interrupt callback.
_voidCallback *	trapvInstCB
	TRAPV instruction interrupt callback.
_voidCallback *	privilegeViolationCB
	Privilege violation exception callback.
_voidCallback *	traceCB
	Trace interrupt callback.
_voidCallback *	line1x1xCB
	Line 1x1x exception callback.
_voidCallback *	errorExceptionCB
	Error exception callback.
_voidCallback *	intCB
	Level interrupt callback.
_voidCallback *	internalVIntCB
	Internal Vertical interrupt callback.
_voidCallback *	internalHIntCB
	Internal Horizontal interrupt callback.
_voidCallback *	internalExtIntCB
	Internal External interrupt callback.

---

Detailed Description

Entry point unit / Interrupt callback / System.

Author:

Stephane Dallongeville

Date:

08/2011

This unit contains SGDK initialization / reset methods, IRQ callbacks and others system stuff.

---

Function Documentation

void SYS_assertReset

(

)

Assert reset.

Assert reset pin on the 68000 CPU. This is needed to reset some attached hardware.

void SYS_die

(

char *

err

)

Die with the specified error message.
Program execution is interrupted.

This actually display an error message and program ends execution.

void SYS_disableInts

(

)

Disable interrupts (Vertical, Horizontal and External).

This method is used to temporary disable interrupt (to protect some VDP accesses for instance) and should always be followed by SYS_enableInts().
Be careful, this method can't be used if you are currently processing an interrupt !

See also:

SYS_enableInts()

void SYS_enableInts

(

)

Reenable interrupts (Vertical, Horizontal and External).

This method is used to reenable interrupt after a call to SYS_disableInts().
Has no effect if called without a prior SYS_disableInts() call.

See also:

SYS_disableInts()

u16 SYS_getAndSetInterruptMaskLevel

(

u16

value

)

Set the interrupt mask level to given value and return previous level.

You can disable interrupt depending their level.
Interrupt with level <= interrupt mask level are ignored.
We have 3 different interrupts:
Vertical interrupt (V-INT): level 6 Horizontal interrupt (H-INT): level 4 External interrupt (EX-INT): level 2 Vertical interrupt has the highest level (and so priority) where external interrupt has lowest one.
For instance to disable Vertical interrupt just use SYS_setInterruptMaskLevel(6).

See also:

SYS_getInterruptMaskLevel()

SYS_setInterruptMaskLevel()

SYS_setVIntCallback()

SYS_setHIntCallback()

u16 SYS_getInterruptMaskLevel

(

)

Return current interrupt mask level.

See SYS_setInterruptMaskLevel() for more informations about interrupt mask level.

u16 SYS_isInExtIntCallback

(

)

Return != 0 if we are in the Ext-Int callback method.

This method tests if we are currently processing an External interrupt.

u16 SYS_isInHIntCallback

(

)

Return != 0 if we are in the H-Int callback method.

This method tests if we are currently processing a Horizontal retrace interrupt.

u16 SYS_isInInterrupt

(

)

Return != 0 if we are in an interrupt callback method (Vertical, Horizontal or External)

This method tests if we are currently processing an interrupt.

u16 SYS_isInVIntCallback

(

)

Return != 0 if we are in the V-Int callback method.

This method tests if we are currently processing a Vertical retrace interrupt.

void SYS_reset

(

)

Soft reset.

Software reset

void SYS_setExtIntCallback

(

_voidCallback *

CB

)

Set External interrupt callback method.

Parameters:

CB	Pointer to the method to call on External Interrupt. You can remove current callback by passing a null pointer here.

External interrupt happen on Light Gun trigger (HVCounter is locked).

void SYS_setHIntCallback

(

_voidCallback *

CB

)

Set Horizontal interrupt callback method.

Parameters:

CB	Pointer to the method to call on Horizontal Interrupt. You can remove current callback by passing a null pointer here.

Horizontal interrupt happen at the end of scanline display period right before Horizontal blank.
This period is usually used to do mid frame changes (palette, scrolling or others raster effect)

void SYS_setInterruptMaskLevel

(

u16

value

)

Set interrupt mask level.

You can disable interrupt depending their level.
Interrupt with level <= interrupt mask level are ignored.
We have 3 different interrupts:
Vertical interrupt (V-INT): level 6 Horizontal interrupt (H-INT): level 4 External interrupt (EX-INT): level 2 Vertical interrupt has the highest level (and so priority) where external interrupt has lowest one.
For instance to disable Vertical interrupt just use SYS_setInterruptMaskLevel(6).

See also:

SYS_getInterruptMaskLevel()

SYS_getAndSetInterruptMaskLevel()

SYS_setVIntCallback()

SYS_setHIntCallback()

void SYS_setVIntCallback

(

_voidCallback *

CB

)

Set Vertical interrupt callback method.

Parameters:

CB	Pointer to the method to call on Vertical Interrupt. You can remove current callback by passing a null pointer here.

Vertical interrupt happen at the end of display period right before vertical blank.
This period is usually used to prepare next frame data (refresh sprites, scrolling ...)

---

Variable Documentation

_voidCallback* addressErrorCB

Address error interrupt callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* busErrorCB

Bus error interrupt callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* chkInstCB

CHK instruction interrupt callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* errorExceptionCB

Error exception callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* illegalInstCB

Illegal instruction exception callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* intCB

Level interrupt callback.

You can modify it to use your own callback.

_voidCallback* internalExtIntCB

Internal External interrupt callback.

You can modify it to use your own callback.
Be careful: by doing that you disable SGDK default Ext-Int code and related features !
You should use it only for very low level process and if you don't care about SGDK facilities.
In all others cases you would use the SYS_setExtIntCallback() method.

_voidCallback* internalHIntCB

Internal Horizontal interrupt callback.

You can modify it to use your own callback.
Be careful: by doing that you disable SGDK default H-Int code and related features !
You should use it only for very low level process and if you don't care about SGDK facilities.
In all others cases you would use the SYS_setHIntCallback() method.

_voidCallback* internalVIntCB

Internal Vertical interrupt callback.

You can modify it to use your own callback.
Be careful: by doing that you disable SGDK default V-Int code and related features !
You should use it only for very low level process and if you don't care about SGDK facilities.
In all others cases you would use the SYS_setVIntCallback() method.

_voidCallback* line1x1xCB

Line 1x1x exception callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* privilegeViolationCB

Privilege violation exception callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* traceCB

Trace interrupt callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* trapvInstCB

TRAPV instruction interrupt callback.

You can modify it to use your own callback (for debug purpose).

_voidCallback* zeroDivideCB

Division by zero exception callback.

You can modify it to use your own callback (for debug purpose).