N64 interrupt registering and servicing routines. More...

Files
file	interrupt.c
	Interrupt Controller.

file	interrupt.h
	Interrupt Controller.

Data Structures
struct	_callback_link
	Structure of an interrupt callback. More...

Macros
#define	MI_INTR_SP 0x01
	SP interrupt bit.

#define	MI_INTR_SI 0x02
	SI interrupt bit.

#define	MI_INTR_AI 0x04
	AI interrupt bit.

#define	MI_INTR_VI 0x08
	VI interrupt bit.

#define	MI_INTR_PI 0x10
	PI interrupt bit.

#define	MI_INTR_DP 0x20
	DP interrupt bit.

#define	MI_MASK_SP 0x01
	SP mask bit.

#define	MI_MASK_SI 0x02
	SI mask bit.

#define	MI_MASK_AI 0x04
	AI mask bit.

#define	MI_MASK_VI 0x08
	VI mask bit.

#define	MI_MASK_PI 0x10
	PI mask bit.

#define	MI_MASK_DP 0x20
	DP mask bit.

#define	MI_MASK_CLR_SP 0x0001
	Clear SP mask.

#define	MI_MASK_SET_SP 0x0002
	Set SP mask.

#define	MI_MASK_CLR_SI 0x0004
	Clear SI mask.

#define	MI_MASK_SET_SI 0x0008
	Set SI mask.

#define	MI_MASK_CLR_AI 0x0010
	Clear AI mask.

#define	MI_MASK_SET_AI 0x0020
	Set AI mask.

#define	MI_MASK_CLR_VI 0x0040
	Clear VI mask.

#define	MI_MASK_SET_VI 0x0080
	Set VI mask.

#define	MI_MASK_CLR_PI 0x0100
	Clear PI mask.

#define	MI_MASK_SET_PI 0x0200
	Set PI mask.

#define	MI_MASK_CLR_DP 0x0400
	Clear DP mask.

#define	MI_MASK_SET_DP 0x0800
	Set DP mask.

#define	PI_CLEAR_INTERRUPT 0x02
	Bit to set to clear the PI interrupt.

#define	SI_CLEAR_INTERRUPT 0
	Bit to set to clear the SI interrupt.

#define	SP_CLEAR_INTERRUPT 0x08
	Bit to set to clear the SP interrupt.

#define	DP_CLEAR_INTERRUPT 0x0800
	Bit to set to clear the DP interrupt.

#define	AI_CLEAR_INTERRUPT 0
	Bit to set to clear the AI interrupt.

Enumerations
enum	interrupt_state_t { INTERRUPTS_UNINITIALIZED , INTERRUPTS_DISABLED , INTERRUPTS_ENABLED }
	State of interrupts on the system. More...

Functions
void	__MI_handler (void)
	Handle an MI interrupt. More...

void	__TI_handler (void)
	Handle a timer interrupt.

void	__CART_handler (void)
	Handle a CART interrupt.

void	register_AI_handler (void(*callback)())
	Register an AI callback. More...

void	unregister_AI_handler (void(*callback)())
	Unregister an AI callback. More...

void	register_VI_handler (void(*callback)())
	Register a VI callback. More...

void	unregister_VI_handler (void(*callback)())
	Unregister a VI callback. More...

void	register_PI_handler (void(*callback)())
	Register a PI callback. More...

void	unregister_PI_handler (void(*callback)())
	Unegister a PI callback. More...

void	register_DP_handler (void(*callback)())
	Register a DP callback. More...

void	unregister_DP_handler (void(*callback)())
	Unregister a DP callback. More...

void	register_SI_handler (void(*callback)())
	Register a SI callback. More...

void	unregister_SI_handler (void(*callback)())
	Unegister a SI callback. More...

void	register_SP_handler (void(*callback)())
	Register a SP callback. More...

void	unregister_SP_handler (void(*callback)())
	Unegister a SP callback. More...

void	register_TI_handler (void(*callback)())
	Register a timer callback. More...

void	unregister_TI_handler (void(*callback)())
	Unregister a timer callback. More...

void	register_CART_handler (void(*callback)())
	Register a CART interrupt callback. More...

void	unregister_CART_handler (void(*callback)())
	Unregister a CART interrupt callback. More...

void	set_AI_interrupt (int active)
	Enable or disable the AI interrupt. More...

void	set_VI_interrupt (int active, unsigned long line)
	Enable or disable the VI interrupt. More...

void	set_PI_interrupt (int active)
	Enable or disable the PI interrupt. More...

void	set_DP_interrupt (int active)
	Enable or disable the DP interrupt. More...

void	set_SI_interrupt (int active)
	Enable or disable the SI interrupt. More...

void	set_SP_interrupt (int active)
	Enable or disable the SP interrupt. More...

void	set_TI_interrupt (int active)
	Enable the timer interrupt. More...

void	set_CART_interrupt (int active)
	Enable the CART interrupt. More...

void	__init_interrupts ()
	Initialize the interrupt controller.

void	disable_interrupts ()
	Disable interrupts systemwide. More...

void	enable_interrupts ()
	Enable interrupts systemwide. More...

interrupt_state_t	get_interrupts_state ()
	Return the current state of interrupts. More...

Variables
uint32_t	interrupt_disabled_tick = 0
	tick at which interrupts were disabled. More...

struct callback_link *	AI_callback = 0
	Linked list of AI callbacks.

struct callback_link *	VI_callback = 0
	Linked list of VI callbacks.

struct callback_link *	PI_callback = 0
	Linked list of PI callbacks.

struct callback_link *	DP_callback = 0
	Linked list of DP callbacks.

struct callback_link *	SI_callback = 0
	Linked list of SI callbacks.

struct callback_link *	SP_callback = 0
	Linked list of SP callbacks.

struct callback_link *	TI_callback = 0
	Linked list of TI callbacks.

struct callback_link *	CART_callback = 0
	Linked list of CART callbacks.

Detailed Description

N64 interrupt registering and servicing routines.

The N64 interrupt controller provides a software interface to register for interrupts from the various systems in the N64. Most interrupts on the N64 coordinate through the MIPS interface (MI) to allow interrupts to be handled at one spot. A notable exception is the timer interrupt which is generated by the MIPS r4300 itself and not the N64 hardware.

The interrupt controller is automatically initialized before main is called. By default, all interrupts are enabled and any registered callback can be called when an interrupt occurs. Each of the N64-generated interrupts is maskable using the various set accessors.

Interrupts can be enabled or disabled as a whole on the N64 using enable_interrupts and disable_interrupts. It is assumed that once the interrupt system is activated, these will always be called in pairs. Calling enable_interrupts without first calling disable_interrupts is considered a violation of this assumption and should be avoided. Calling disable_interrupts when interrupts are already disabled will have no effect. Calling enable_interrupts again to restore from a critical section will not enable interrupts if interrupts were not enabled when calling disable_interrupts. In this manner, it is safe to nest calls to disable and enable interrupts.

Enumeration Type Documentation

◆ interrupt_state_t

enum interrupt_state_t

State of interrupts on the system.

Enumerator
INTERRUPTS_UNINITIALIZED	Interrupt controller has not been initialized.
INTERRUPTS_DISABLED	Interrupts are currently disabled.
INTERRUPTS_ENABLED	Interrupts are currently enabled.

Function Documentation

◆ __MI_handler()

void __MI_handler ( void )

Handle an MI interrupt.

Note: This function handles most of the interrupts on the system as they come through the MI.

◆ register_AI_handler()

void register_AI_handler ( void(*)() callback )

Register an AI callback.

Parameters

[in] callback Function to call when an AI interrupt occurs

◆ unregister_AI_handler()

void unregister_AI_handler ( void(*)() callback )

Unregister an AI callback.

Parameters

[in] callback Function that should no longer be called on AI interrupts

◆ register_VI_handler()

void register_VI_handler ( void(*)() callback )

Register a VI callback.

Parameters

[in] callback Function to call when a VI interrupt occurs

◆ unregister_VI_handler()

void unregister_VI_handler ( void(*)() callback )

Unregister a VI callback.

Parameters

[in] callback Function that should no longer be called on VI interrupts

◆ register_PI_handler()

void register_PI_handler ( void(*)() callback )

Register a PI callback.

Parameters

[in] callback Function to call when a PI interrupt occurs

◆ unregister_PI_handler()

void unregister_PI_handler ( void(*)() callback )

Unegister a PI callback.

Parameters

[in] callback Function that should no longer be called on PI interrupts

◆ register_DP_handler()

void register_DP_handler ( void(*)() callback )

Register a DP callback.

Parameters

[in] callback Function to call when a DP interrupt occurs

◆ unregister_DP_handler()

void unregister_DP_handler ( void(*)() callback )

Unregister a DP callback.

Parameters

[in] callback Function that should no longer be called on DP interrupts

◆ register_SI_handler()

void register_SI_handler ( void(*)() callback )

Register a SI callback.

Parameters

[in] callback Function to call when a SI interrupt occurs

◆ unregister_SI_handler()

void unregister_SI_handler ( void(*)() callback )

Unegister a SI callback.

Parameters

[in] callback Function that should no longer be called on SI interrupts

◆ register_SP_handler()

void register_SP_handler ( void(*)() callback )

Register a SP callback.

Parameters

[in] callback Function to call when a SP interrupt occurs

◆ unregister_SP_handler()

void unregister_SP_handler ( void(*)() callback )

Unegister a SP callback.

Parameters

[in] callback Function that should no longer be called on SP interrupts

◆ register_TI_handler()

void register_TI_handler ( void(*)() callback )

Register a timer callback.

The callback will be used when the timer interrupt is triggered by the CPU. This happens when the COP0 COUNT register reaches the same value of the COP0 COMPARE register.

This function is useful only if you want to do your own low level programming of the internal CPU timer and handle the interrupt yourself. In this case, also remember to activate the timer interrupt using set_TI_interrupt.

Note: If you use the timer library (timer_init and new_timer), you do not need to call this function, as timer interrupt are already handled by the timer library.

Parameters

[in] callback Function to call when a timer interrupt occurs

◆ unregister_TI_handler()

void unregister_TI_handler ( void(*)() callback )

Unregister a timer callback.

Note: If you use the timer library (timer_init and new_timer), you do not need to call this function, as timer interrupt are already handled by the timer library.

Parameters

[in] callback Function that should no longer be called on timer interrupts

◆ register_CART_handler()

void register_CART_handler ( void(*)() callback )

Register a CART interrupt callback.

The callback will be called when a CART interrupt is triggered. CART interrupts are interrupts triggered by devices attached to the PI bus (aka CART bus), for instance the 64DD, or the modem cassette.

CART interrupts are disabled by default in libdragon. Use set_CART_interrupt to enable/disable them.

Notice that there is no generic way to acknowledge those interrupts, so if you activate CART interrupts, make also sure to register an handler that acknowledge them, otherwise the interrupt will deadlock the console.

Parameters

[in] callback Function that should no longer be called on CART interrupts

◆ unregister_CART_handler()

void unregister_CART_handler ( void(*)() callback )

Unregister a CART interrupt callback.

Parameters

[in] callback Function that should no longer be called on CART interrupts

◆ set_AI_interrupt()

void set_AI_interrupt ( int active )

Enable or disable the AI interrupt.

Parameters

[in] active Flag to specify whether the AI interrupt should be active

◆ set_VI_interrupt()

void set_VI_interrupt	(	int	active,
		unsigned long	line
	)

Enable or disable the VI interrupt.

Parameters

[in]	active	Flag to specify whether the VI interrupt should be active
[in]	line	The vertical line that causes this interrupt to fire. Ignored when setting the interrupt inactive

◆ set_PI_interrupt()

void set_PI_interrupt ( int active )

Enable or disable the PI interrupt.

Parameters

[in] active Flag to specify whether the PI interrupt should be active

◆ set_DP_interrupt()

void set_DP_interrupt ( int active )

Enable or disable the DP interrupt.

Parameters

[in] active Flag to specify whether the DP interrupt should be active

◆ set_SI_interrupt()

void set_SI_interrupt ( int active )

Enable or disable the SI interrupt.

Parameters

[in] active Flag to specify whether the SI interrupt should be active

◆ set_SP_interrupt()

void set_SP_interrupt ( int active )

Enable or disable the SP interrupt.

Parameters

[in] active Flag to specify whether the SP interrupt should be active

◆ set_TI_interrupt()

void set_TI_interrupt ( int active )

Enable the timer interrupt.

Note: If you use the timer library (timer_init and new_timer), you do not need to call this function, as timer interrupt is already handled by the timer library.

Parameters

[in] active Flag to specify whether the timer interrupt should be active

See also: register_TI_handler

◆ set_CART_interrupt()

void set_CART_interrupt ( int active )

Enable the CART interrupt.

Parameters

[in] active Flag to specify whether the CART interrupt should be active

See also: register_CART_handler

◆ disable_interrupts()

void disable_interrupts ( )

Disable interrupts systemwide.

Note: If interrupts are already disabled on the system or interrupts have not been initialized, this function will not modify the system state.

◆ enable_interrupts()

void enable_interrupts ( )

Enable interrupts systemwide.

Note: If this is called inside a nested disable call, it will have no effect on the system. Therefore it is safe to nest disable/enable calls. After the last nested interrupt is enabled, systemwide interrupts will be reenabled.

◆ get_interrupts_state()

interrupt_state_t get_interrupts_state ( )

Return the current state of interrupts.

Return values

INTERRUPTS_UNINITIALIZED	if the interrupt system has not been initialized yet.
INTERRUPTS_DISABLED	if interrupts have been disabled for some reason.
INTERRUPTS_ENABLED	if interrupts are currently enabled.

Variable Documentation

◆ interrupt_disabled_tick

uint32_t interrupt_disabled_tick = 0

tick at which interrupts were disabled.

Time at which interrupts were disabled.

Files

Data Structures

Macros

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ interrupt_state_t

Function Documentation

◆ __MI_handler()

◆ register_AI_handler()

◆ unregister_AI_handler()

◆ register_VI_handler()

◆ unregister_VI_handler()

◆ register_PI_handler()

◆ unregister_PI_handler()

◆ register_DP_handler()

◆ unregister_DP_handler()

◆ register_SI_handler()

◆ unregister_SI_handler()

◆ register_SP_handler()

◆ unregister_SP_handler()

◆ register_TI_handler()

◆ unregister_TI_handler()

◆ register_CART_handler()

◆ unregister_CART_handler()

◆ set_AI_interrupt()

◆ set_VI_interrupt()

◆ set_PI_interrupt()

◆ set_DP_interrupt()

◆ set_SI_interrupt()

◆ set_SP_interrupt()

◆ set_TI_interrupt()

◆ set_CART_interrupt()

◆ disable_interrupts()

◆ enable_interrupts()

◆ get_interrupts_state()

Variable Documentation

◆ interrupt_disabled_tick