snes interrupt support. More...

#include <snes/snestypes.h>

Macros
#define	HBL_READY (1 << 6)
	H-Blank Period Flag (0=No, 1=HBlank)

#define	INT_HVIRQ_H (1 << 4)
	H/V IRQ (0=Disable, 1=At H=H + V=Any, 2=At V=V + H=0, 3=At H=H + V=V)

#define	INT_HVIRQ_HV (2 << 4)
	H/V IRQ (0=Disable, 1=At H=H + V=Any, 2=At V=V + H=0, 3=At H=H + V=V)

#define	INT_HVIRQ_V (1 << 5)
	H/V IRQ (0=Disable, 1=At H=H + V=Any, 2=At V=V + H=0, 3=At H=H + V=V)

#define	INT_JOYPAD_ENABLE (1)
	Joypad Enable (0=Disable, 1=Enable Automatic Reading of Joypad)

#define	INT_VBLENABLE (1 << 7)
	VBlank NMI Enable (0=Disable, 1=Enable) (Initially disabled on reset)

#define	nmiSet(handler) nmi_handler = handler;
	Add a handler for the given interrupt mask. More...

#define	PAD_BUSY (1)
	Auto-Joypad-Read Busy Flag (1=Busy) (see 4200h, and 4218h..421Fh)

#define	REG_HVBJOY ((vuint8 )0x4212)
	H/V-Blank flag and Joypad Busy flag (R). More...

#define	REG_NMITIMEN ((vuint8 )0x4200)
	Interrupt Enable and Joypad Request (W). More...

#define	REG_RDNMI ((vuint8 )0x4210)
	V-Blank NMI Flag and CPU Version Number (R) (Read/Ack) More...

#define	REG_TIMEUP ((vuint8 )0x4211)
	TIMEUP - H/V-Timer IRQ Flag (R) (Read/Ack) More...

#define	VBL_READY (1 << 7)
	V-Blank Period Flag (0=No, 1=VBlank)

#define	WaitVBLFlag
	Wait for VBL flag to be OK

Functions
void	WaitForVBlank (void)
	Wait for vblank interrupt More...

void	WaitNVBlank (u16 ntime)
	Wait for vblank interrupt ntime times More...

Detailed Description

snes interrupt support.

Macro Definition Documentation

◆ nmiSet

#define nmiSet ( handler ) nmi_handler = handler;

Add a handler for the given interrupt mask.

Specify the handler to use for the nmi interrupt.

Parameters

handler Address of the function to use as an interrupt service routine

Examples: graphics/Backgrounds/Mode1ContinuosScroll/Mode1ContinuosScroll.c, and graphics/Sprites/DynamicSprite/DynamicSprite.c.

◆ REG_HVBJOY

#define REG_HVBJOY (*(vuint8 *)0x4212)

H/V-Blank flag and Joypad Busy flag (R).

7 V-Blank Period Flag (0=No, 1=VBlank)
6 H-Blank Period Flag (0=No, 1=HBlank)
5-1 Not used
0 Auto-Joypad-Read Busy Flag (1=Busy) (see 4200h, and 4218h..421Fh)

The Hblank flag gets toggled in ALL scanlines (including during Vblank/Vsync).
Both Vblank and Hblank are always toggling (even during Forced Blank,
and no matter if IRQs or NMIs are enabled

◆ REG_NMITIMEN

#define REG_NMITIMEN (*(vuint8 *)0x4200)

Interrupt Enable and Joypad Request (W).

7 VBlank NMI Enable (0=Disable, 1=Enable) (Initially disabled on reset)
6 Not used
5-4 H/V IRQ (0=Disable, 1=At H=H + V=Any, 2=At V=V + H=0, 3=At H=H + V=V)
3-1 Not used
0 Joypad Enable (0=Disable, 1=Enable Automatic Reading of Joypad)

Disabling IRQs (via bit4-5) does additionally acknowledge IRQs.
There's no such effect when disabling NMIs (via bit7).

◆ REG_RDNMI

#define REG_RDNMI (*(vuint8 *)0x4210)

V-Blank NMI Flag and CPU Version Number (R) (Read/Ack)

7 Vblank NMI Flag (0=None, 1=Interrupt Request) (set on Begin of Vblank)
6-4 Not used
3-0 CPU 5A22 Version Number (version 2 exists)

The NMI flag gets set at begin of Vblank (this happens even if NMIs are disabled). The flag gets reset automatically
at end of Vblank, and gets also reset after reading from this register.
The SNES has only one NMI source (vblank), and the NMI flag is automatically reset (on vblank end), so there's
normally no need to read/acknowledge the flag, except one special case: If one does disable and re-enable NMIs,
then an old NMI may be executed again; acknowledging avoids that effect.
The CPU includes another internal NMI flag, which gets set when "[4200h].7 AND [4210h].7" changes from 0-to-1, and
gets cleared when the NMI gets executed (which should happen around after the next opcode) (if a DMA transfer is
in progress, then it is somewhere after the DMA, in that case the NMI can get executed outside of the Vblank
period, ie. at a time when [4210h].7 is no longer set).

◆ REG_TIMEUP

#define REG_TIMEUP (*(vuint8 *)0x4211)

TIMEUP - H/V-Timer IRQ Flag (R) (Read/Ack)

7 H/V-Count Timer IRQ Flag (0=None, 1=Interrupt Request)
6-0 Not used

The IRQ flag is automatically reset after reading from this register
(except when reading at the very time when the IRQ condition is true
(which lasts for 4-8 master cycles), then the CPU receives bit7=1,
but register bit7 isn't cleared). The flag is also automatically cleared
when disabling IRQs (by setting 4200h.Bit5-4 to zero).
Unlike NMI handlers, IRQ handlers MUST acknowledge IRQs, otherwise the IRQ
gets executed again (ie. immediately after the RTI opcode).

Function Documentation

◆ WaitForVBlank()

void WaitForVBlank ( void )

Wait for vblank interrupt

Waits for a vertical blank interrupt

Examples: audio/effects/effects.c, audio/effectsandmusic/effectsandmusic.c, audio/music/Music.c, audio/musicGreaterThan32k/musicGreaterThan32k.c, audio/tada/Tada.c, breakpoints/src/breakpoints.c, debug/debug.c, games/breakout/breakout.c, games/likemario/LikeMario.c, graphics/Backgrounds/Mode0/Mode0.c, graphics/Backgrounds/Mode1/Mode1.c, graphics/Backgrounds/Mode1BG3HighPriority/Mode1BG3HighPriority.c, graphics/Backgrounds/Mode1ContinuosScroll/Mode1ContinuosScroll.c, graphics/Backgrounds/Mode1LZ77/Mode1LZ77.c, graphics/Backgrounds/Mode1MixedScroll/Mode1MixedScroll.c, graphics/Backgrounds/Mode1Png/Mode1.c, graphics/Backgrounds/Mode1Scroll/Mode1Scroll.c, graphics/Backgrounds/Mode3/Mode3.c, graphics/Backgrounds/Mode5/Mode5.c, graphics/Backgrounds/Mode7/Mode7.c, graphics/Backgrounds/Mode7Perspective/Mode7Perspective.c, graphics/Effects/Fading/Fading.c, graphics/Effects/GradientColors/GradientColors.c, graphics/Effects/HDMAGradient/HDMAGradient.c, graphics/Effects/MosaicShading/MosaicShading.c, graphics/Effects/ParallaxScrolling/ParallaxScrolling.c, graphics/Effects/Transparency/Transparency.c, graphics/Effects/TransparentWindow/src/main.c, graphics/Effects/Waves/Waves.c, graphics/Effects/Window/Window.c, graphics/Palette/GetColors/GetColors.c, graphics/Sprites/AnimatedSprite/AnimatedSprite.c, graphics/Sprites/DynamicEngineMetaSprite/DynamicEngineMetaSprite.c, graphics/Sprites/DynamicEngineSprite/DynamicEngineSprite.c, graphics/Sprites/DynamicSprite/DynamicSprite.c, graphics/Sprites/ObjectSize/ObjectSize.c, graphics/Sprites/SimpleSprite/SimpleSprite.c, hello_world/src/hello_world.c, input/controller/controller.c, input/mouse/mouse.c, input/multiplay5/multiplay5.c, input/superscope/superscope.c, maps/mapscroll/mapscroll.c, maps/tiled/tiled.c, memory_mapping/src/memory_mapping.c, objects/mapandobjects/mapandobjects.c, objects/moveobjects/moveobjects.c, objects/nogravityobject/nogravityobjects.c, random/random.c, scoring/scoring.c, sram/sramoffset/sramoffset.c, sram/sramsimple/sram.c, testregion/testregion.c, timer/timer.c, and typeconsole/src/pal_ntsc.c.

◆ WaitNVBlank()

void WaitNVBlank ( u16 ntime )

Wait for vblank interrupt ntime times