ARM11 Interrupts

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Interrupts[edit]

Interrupt priority is 0-0xF. A priority of 0xF means that the interrupt is disabled.

Private Interrupts[edit]

Each CPU core has 32 software interrupts that are private and belong to that core. These interrupts are numbers 0-0x1F for each core. The hardware interrupts are not core-specific and start at interrupt ID 0x20.

IRQ Listener Description
0-0x3 MPCore software-interrupt. Not configured.
0x4 Kernel MPCore software-interrupt. Used to manage the performance counter.
0x5 Kernel MPCore software-interrupt. Does apparently nothing.
0x6 Kernel MPCore software-interrupt. Extensively used by KernelSetState (and contains most of the actual code of the latter).
0x7 Kernel MPCore software-interrupt. See KCacheMaintenanceInterruptEvent
0x8 Kernel MPCore software-interrupt. Used for scheduling.
0x9 Kernel MPCore software-interrupt. Used when handling exceptions that require termination of a thread or a process, and in some cases by svcSetDebugThreadContext, to store VFP registers in the thread's register storage.
0xA Kernel TLB operations interrupt, see KTLBOperationsInterruptEvent
0xB-0xE MPCore software-interrupt. Not configured.
0xF dmnt/debugger MPCore software-interrupt. Used to abstract FIQ (debug). This interrupt is never sent to core2 nor core3 on N3DS.
0x1D Kernel MPCore timer.
0x1E Kernel MPCore watchdog - set when the watchdog counter reaches 0 in timer mode, causes interrupt 30 to set as pending. Only set on core 1 as core 1's timer is used for everything.

Hardware Interrupts[edit]

There are 0x60 hardware interrupts starting at 0x20 and continuing up to 0x7F. These are not private and are accessible from any core.

IRQ Listener Description
0x28 gsp, TwlBg PSC0
0x29 gsp, TwlBg PSC1
0x2A gsp, TwlBg PDC0 (VBlank0)
0x2B gsp, TwlBg PDC1 (VBlank1)
0x2C gsp, TwlBg PPF
0x2D gsp, TwlBg P3D?
0x30 Kernel  ?
0x39 Kernel DMA
0x3A Kernel DMA
0x3B Kernel DMA
0x40 nwm WIFI SDIO Controller @ 0x10122000
0x41 nwm  ?
0x42 nwm_dev? WIFI SDIO Controller @ 0x10100000
0x45 mvd (New3DS)  ?
0x46 mvd (New3DS)  ?
0x48 camera  ?
0x49 camera  ?
0x4A dsp  ?
0x4B camera Y2R Conversion Finished
0x4C TwlBg  ?
0x4D TwlBg  ?
0x4E mvd (New3DS)  ?
0x4F mvd (New3DS)  ?
0x50 pxi, TwlBg Sync
0x51 pxi, TwlBg  ?
0x52 pxi, TwlBg Send Fifo Empty
0x53 pxi, TwlBg Receive Fifo Not Empty
0x54 i2c, TwlBg I2C Bus0 work done
0x55 i2c, TwlBg I2C Bus1 work done
0x56 spi, TwlBg  ?
0x57 spi, TwlBg  ?
0x58 Kernel PDN
0x59 TwlBg  ?
0x5A mic  ?
0x5C i2c, TwlBg I2C Bus2 work done
0x60 gpio, TwlBg Shell opened
0x62 gpio, TwlBg Shell closed
0x63 gpio, TwlBg Touchscreen
0x64 gpio, TwlBg Headphone jack plugged in/out
0x66 gpio, TwlBg  ?
0x68 gpio, TwlBg IR
0x69 gpio, TwlBg  ?
0x6A gpio, TwlBg  ?
0x6B gpio, TwlBg  ?
0x6C gpio, TwlBg  ?
0x6D gpio, TwlBg  ?
0x6E gpio, TwlBg  ?
0x6F gpio, TwlBg  ?
0x70 gpio, TwlBg  ?
0x71 gpio, TwlBg MCU (HOME/POWER pressed/released or WiFi switch pressed)
0x72 gpio, TwlBg  ?
0x73 TwlBg  ?
0x74  ? Gamecard related
0x75  ? Gamecard inserted
0x78 to 0x7C Kernel Performance monitor-related
0x7A to 0x82 (PDN_MPCORE_CFG bit2 set) or

0x7C to 0x84 (bit2 clear)

Kernel Performance monitor counter no. X overflowed

(interrupts from 0x80 and up can't be mapped in available builds of the kernel)


There are 2 tables in the ARM11 kernel: the first has 32 * 2(or 32 * 4) 8-byte entries. This table is for the private interrupts that belong to each core. The data for each interrupt can be found by doing table_base + (core_num * 0x100) + (intr_num * 8). The second table is for public hardware interrupts and the data for each interrupt can be retrieved by doing table_base + (intr_num * 8).

InterruptData[edit]

Offset Type Description
0x0 KBaseInterruptEvent * Pointer to the KBaseInterruptEvent object for this interrupt
0x4 u8 Interrupt will be disabled by the IRQ handler as soon as it is acknowledged.

Ignored for FIQ: the FIQ handler always sets bit2 of PDN_FIQ_CNT

0x5 u8 Interrupt is disabled
0x6 u8 Interrupt priority
0x7 u8 Unused, alignment

Interrupt Table (New3DS)[edit]

(0xFFF318F4 in 10.3)

Offset Type Description
0x0 InterruptData[224] Data for all hardware and software interrupts
0x700 KObjectMutex Mutex