Interrupt and exception handling. More...

#include <sys/cdefs.h>
#include <arch/types.h>

Data Structures
struct	irq_context
	Architecture-specific structure for holding the processor state. More...

Macros
#define	REG_BYTE_CNT 256 /* Currently really 228 */
	The number of bytes required to save thread context.
#define	CONTEXT_PC(c) ((c).pc)
	Fetch the program counter from an irq_context_t.
#define	CONTEXT_FP(c) ((c).r[14])
	Fetch the frame pointer from an irq_context_t.
#define	CONTEXT_SP(c) ((c).r[15])
	Fetch the stack pointer from an irq_context_t.
#define	CONTEXT_RET(c) ((c).r[0])
	Fetch the return value from an irq_context_t.
#define	EXC_RESET_POWERON 0x0000
	Power-on reset.
#define	EXC_RESET_MANUAL 0x0020
	Manual reset.
#define	EXC_RESET_UDI 0x0000
	Hitachi UDI reset.
#define	EXC_ITLB_MULTIPLE 0x0140
	Instruction TLB multiple hit.
#define	EXC_DTLB_MULTIPLE 0x0140
	Data TLB multiple hit.
#define	EXC_USER_BREAK_PRE 0x01e0
	User break before instruction.
#define	EXC_INSTR_ADDRESS 0x00e0
	Instruction address.
#define	EXC_ITLB_MISS 0x0040
	Instruction TLB miss.
#define	EXC_ITLB_PV 0x00a0
	Instruction TLB protection violation.
#define	EXC_ILLEGAL_INSTR 0x0180
	Illegal instruction.
#define	EXC_SLOT_ILLEGAL_INSTR 0x01a0
	Slot illegal instruction.
#define	EXC_GENERAL_FPU 0x0800
	General FPU exception.
#define	EXC_SLOT_FPU 0x0820
	Slot FPU exception.
#define	EXC_DATA_ADDRESS_READ 0x00e0
	Data address (read)
#define	EXC_DATA_ADDRESS_WRITE 0x0100
	Data address (write)
#define	EXC_DTLB_MISS_READ 0x0040
	Data TLB miss (read)
#define	EXC_DTLB_MISS_WRITE 0x0060
	Data TLB miss (write)
#define	EXC_DTLB_PV_READ 0x00a0
	Data TLB protection violation (read)
#define	EXC_DTLB_PV_WRITE 0x00c0
	Data TLB protection violation (write)
#define	EXC_FPU 0x0120
	FPU exception.
#define	EXC_INITIAL_PAGE_WRITE 0x0080
	Initial page write exception.
#define	EXC_TRAPA 0x0160
	Unconditional trap (trapa)
#define	EXC_USER_BREAK_POST 0x01e0
	User break after instruction.
#define	EXC_NMI 0x01c0
	Nonmaskable interrupt.
#define	EXC_IRQ0 0x0200
	External IRQ request (level 0)
#define	EXC_IRQ1 0x0220
	External IRQ request (level 1)
#define	EXC_IRQ2 0x0240
	External IRQ request (level 2)
#define	EXC_IRQ3 0x0260
	External IRQ request (level 3)
#define	EXC_IRQ4 0x0280
	External IRQ request (level 4)
#define	EXC_IRQ5 0x02a0
	External IRQ request (level 5)
#define	EXC_IRQ6 0x02c0
	External IRQ request (level 6)
#define	EXC_IRQ7 0x02e0
	External IRQ request (level 7)
#define	EXC_IRQ8 0x0300
	External IRQ request (level 8)
#define	EXC_IRQ9 0x0320
	External IRQ request (level 9)
#define	EXC_IRQA 0x0340
	External IRQ request (level 10)
#define	EXC_IRQB 0x0360
	External IRQ request (level 11)
#define	EXC_IRQC 0x0380
	External IRQ request (level 12)
#define	EXC_IRQD 0x03a0
	External IRQ request (level 13)
#define	EXC_IRQE 0x03c0
	External IRQ request (level 14)
#define	EXC_TMU0_TUNI0 0x0400
	TMU0 underflow.
#define	EXC_TMU1_TUNI1 0x0420
	TMU1 underflow.
#define	EXC_TMU2_TUNI2 0x0440
	TMU2 underflow.
#define	EXC_TMU2_TICPI2 0x0460
	TMU2 input capture.
#define	EXC_RTC_ATI 0x0480
	RTC alarm interrupt.
#define	EXC_RTC_PRI 0x04a0
	RTC periodic interrupt.
#define	EXC_RTC_CUI 0x04c0
	RTC carry interrupt.
#define	EXC_SCI_ERI 0x04e0
	SCI Error receive.
#define	EXC_SCI_RXI 0x0500
	SCI Receive ready.
#define	EXC_SCI_TXI 0x0520
	SCI Transmit ready.
#define	EXC_SCI_TEI 0x0540
	SCI Transmit error.
#define	EXC_WDT_ITI 0x0560
	Watchdog timer.
#define	EXC_REF_RCMI 0x0580
	Memory refresh compare-match interrupt.
#define	EXC_REF_ROVI 0x05a0
	Memory refresh counter overflow interrupt.
#define	EXC_UDI 0x0600
	Hitachi UDI.
#define	EXC_GPIO_GPIOI 0x0620
	I/O port interrupt.
#define	EXC_DMAC_DMTE0 0x0640
	DMAC transfer end (channel 0)
#define	EXC_DMAC_DMTE1 0x0660
	DMAC transfer end (channel 1)
#define	EXC_DMAC_DMTE2 0x0680
	DMAC transfer end (channel 2)
#define	EXC_DMAC_DMTE3 0x06a0
	DMAC transfer end (channel 3)
#define	EXC_DMA_DMAE 0x06c0
	DMAC address error.
#define	EXC_SCIF_ERI 0x0700
	SCIF Error receive.
#define	EXC_SCIF_RXI 0x0720
	SCIF Receive ready.
#define	EXC_SCIF_BRI 0x0740
	SCIF break.
#define	EXC_SCIF_TXI 0x0760
	SCIF Transmit ready.
#define	EXC_DOUBLE_FAULT 0x0ff0
	Double fault.
#define	EXC_UNHANDLED_EXC 0x0fe0
	Unhandled exception.
#define	TIMER_IRQ EXC_TMU0_TUNI0
	The value of the timer IRQ.

#define	EXC_OFFSET_000 0
	irq_type_offsets Exception type offsets
#define	EXC_OFFSET_100 1
	Offset 0x100.
#define	EXC_OFFSET_400 2
	Offset 0x400.
#define	EXC_OFFSET_600 3
	Offset 0x600.

Typedefs
typedef struct irq_context	irq_context_t
	Architecture-specific structure for holding the processor state.
typedef uint32	irq_t
	The type of an interrupt identifier.
typedef void(*	irq_handler )(irq_t source, irq_context_t *context)
	The type of an IRQ handler.

Functions
int	irq_inside_int ()
	Are we inside an interrupt handler?
void	irq_force_return ()
	Pretend like we just came in from an interrupt and force a context switch back to the "current" context.
int	irq_set_handler (irq_t source, irq_handler hnd)
	Set or remove an IRQ handler.
irq_handler	irq_get_handler (irq_t source)
	Get the address of the current handler for the IRQ type.
int	trapa_set_handler (irq_t code, irq_handler hnd)
	Set or remove a handler for a trapa code.
int	irq_set_global_handler (irq_handler hnd)
	Set a global exception handler.
irq_handler	irq_get_global_handler ()
	Get the global exception handler.
void	irq_set_context (irq_context_t *regbank)
	Switch out contexts (for interrupt return).
irq_context_t *	irq_get_context ()
	Get the current IRQ context.
void	irq_create_context (irq_context_t context, uint32 stack_pointer, uint32 routine, uint32 args, int usermode)
	Fill a newly allocated context block for usage with supervisor or user mode.
int	irq_disable ()
	Disable interrupts.
void	irq_enable ()
	Enable all interrupts.
void	irq_restore (int v)
	Restore IRQ state.
int	irq_init ()
	Initialize interrupts.
void	irq_shutdown ()
	Shutdown interrupts, restoring the state to how it was before irq_init() was called.

Detailed Description

Interrupt and exception handling.

This file contains various definitions and declarations related to handling interrupts and exceptions on the Dreamcast. This level deals with IRQs and exceptions generated on the SH4, versus the asic layer which deals with actually differentiating "external" interrupts.

Author:: Dan Potter

See also:: dc/asic.h

Macro Definition Documentation

#define CONTEXT_FP ( c ) ((c).r[14])

Fetch the frame pointer from an irq_context_t.

Parameters:

c	The context to read from.

Returns:: The frame pointer value.

#define CONTEXT_PC ( c ) ((c).pc)

Fetch the program counter from an irq_context_t.

Parameters:

c	The context to read from.

Returns:: The program counter value.

#define CONTEXT_RET ( c ) ((c).r[0])

Fetch the return value from an irq_context_t.

Parameters:

c	The context to read from.

Returns:: The return value.

#define CONTEXT_SP ( c ) ((c).r[15])

Fetch the stack pointer from an irq_context_t.

Parameters:

c	The context to read from.

Returns:: The stack pointer value.

#define EXC_OFFSET_000 0

irq_type_offsets Exception type offsets

The following are a table of "type offsets" (see the Hitachi PDF). These are the 0x000, 0x100, 0x400, and 0x600 offsets. Offset 0x000

#define EXC_OFFSET_100 1

Offset 0x100.

#define EXC_OFFSET_400 2

Offset 0x400.

#define EXC_OFFSET_600 3

Offset 0x600.

#define REG_BYTE_CNT 256 /* Currently really 228 */

The number of bytes required to save thread context.

This should include all general CPU registers, FP registers, and status regs (even if not all of these are actually used).

On the Dreamcast, we need 228 bytes for all of that, but we round it up to a nicer number for sanity.

#define TIMER_IRQ EXC_TMU0_TUNI0

The value of the timer IRQ.

Typedef Documentation

typedef struct irq_context irq_context_t

Architecture-specific structure for holding the processor state.

This structure should hold register values and other important parts of the processor state. The size of this structure should be less than or equal to the REG_BYTE_CNT value.

typedef void(* irq_handler)(irq_t source, irq_context_t *context)

The type of an IRQ handler.

Parameters:

source	The IRQ that caused the handler to be called.
context	The CPU's context.

typedef uint32 irq_t

The type of an interrupt identifier.

Function Documentation

void irq_create_context	(	irq_context_t *	context,
		uint32	stack_pointer,
		uint32	routine,
		uint32 *	args,
		int	usermode
	)

Fill a newly allocated context block for usage with supervisor or user mode.

The given parameters will be passed to the called routine (up to the architecture maximum). For the Dreamcast, this maximum is 4.

Parameters:

context	The IRQ context to fill in.
stack_pointer	The value to set in the stack pointer.
routine	The address of the program counter for the context.
args	Any arguments to set in the registers. This cannot be NULL, and must have enough values to fill in up to the architecture maximum.
usermode	1 to run the routine in user mode, 0 for supervisor.

int irq_disable ( )

Disable interrupts.

This function will disable interrupts, but will leave exceptions enabled.

Returns:: The state of IRQs before calling the function. This can be used to restore this state later on with irq_restore().

void irq_enable ( )

Enable all interrupts.

This function will enable ALL interrupts, including external ones.

void irq_force_return ( )

Pretend like we just came in from an interrupt and force a context switch back to the "current" context.

Make sure you've called irq_set_context() before doing this!

irq_context_t* irq_get_context ( )

Get the current IRQ context.

This will fetch the processor context prior to the exception handling during an IRQ service routine.

Returns:: The current IRQ context.

irq_handler irq_get_global_handler ( )

Get the global exception handler.

Returns:: The global exception handler set with irq_set_global_handler(), or NULL if none is set.

irq_handler irq_get_handler ( irq_t source )

Get the address of the current handler for the IRQ type.

Parameters:

source The IRQ type to look up.

Returns:: A pointer to the procedure to handle the exception.

int irq_init ( )

Initialize interrupts.

Return values:

0	On success (no error conditions defined).

int irq_inside_int ( )

Are we inside an interrupt handler?

Return values:

1	If interrupt handling is in progress.
0	If normal processing is in progress.

void irq_restore ( int v )

Restore IRQ state.

This function will restore the interrupt state to the value specified. This should correspond to a value returned by irq_disable().

Parameters:

v	The IRQ state to restore. This should be a value returned by irq_disable().

void irq_set_context ( irq_context_t * regbank )

Switch out contexts (for interrupt return).

This function will set the processor state that will be restored when the exception returns.

Parameters:

regbank The values of all registers to be restored.

int irq_set_global_handler ( irq_handler hnd )

Set a global exception handler.

This function sets a global catch-all handler for all exception types.

Parameters:

hnd	A pointer to the procedure to handle the exception.

Return values:

0	On success (no error conditions defined).

Note:: The specific handler will still be called for the exception if one is set. If not, setting one of these will stop the unhandled exception error.

int irq_set_handler	(	irq_t	source,
		irq_handler	hnd
	)

Set or remove an IRQ handler.

Passing a NULL value for hnd will remove the current handler, if any.

Parameters:

source	The IRQ type to set the handler for (see SH4 exception codes).
hnd	A pointer to a procedure to handle the exception.

Return values:

0	On success.
-1	If the source is invalid.

void irq_shutdown ( )

Shutdown interrupts, restoring the state to how it was before irq_init() was called.

int trapa_set_handler	(	irq_t	code,
		irq_handler	hnd
	)

Set or remove a handler for a trapa code.

Parameters:

code	The value passed to the trapa opcode.
hnd	A pointer to the procedure to handle the trap.

Return values:

0	On success.
-1	If the code is invalid (greater than 0xFF).

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

Typedef Documentation

Function Documentation