HID Shared Memory

This page describes the format of the HID shared memory.

The data for each of the below entries(PAD state, circle-pad, touch-screen, etc) is originally written by the HID module at different times per frame.

size: 0x2b0 (FIRM 4.4)

Offset 0x0

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x1C	0x4	PAD state. Bit set = button pressed, bit clear = button not pressed. Bit28-31 do not apply to this entry, but they apply to further PAD state entries. Bit28-31 are set when the corresponding circle pad coordinate is >=41 (or <=-41).
0x20	0x4	Raw circle-pad info.
0x28	0x80	Array of 8 entries, where each entry(see below) is 0x10-bytes.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x4	Current PAD state.
0x4	0x4	PAD state for keys which were pressed(bitmasks which changed from value 0 to value 1) since the last HID update.
0x8	0x4	PAD state for keys which were released(bitmasks which changed from value 1 to value 0) since the last HID update.
0xC	0x4	This stores circle-pad info: the low s16 is the X coordinate, the high s16 is the Y coordinate. The circle-pad center is approximately 0 for these fields. The range for these fields is approximately: -0x9C(bottom/left) - 0x9C(top/right).

Offset 0xA8

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x8	Touch-screen entry, which contains the raw coordinate data prior to being converted to pixel coordinates.
0x20	0x40	8 Touch-screen entries, containing pixel coordinates.

This 0x60-byte region stores state for touch-screen related info. Each touch-screen entry is all-zero when the touch-screen is not being touched.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x2	X coordinate.
0x2	0x2	Y coordinate.
0x4	0x4	The u8 at +0 here is 0x0 when this entry doesn't contain any actual data, value 0x1 indicates that this entry contains actual data.

Offset 0x108

The size of this region is 0x50-bytes. This contains the accelerometer state.

Offset 0x158

The size of this region is 0xE0-bytes. Initially this contains 0xFF/0x00 bytes. This contains the gyroscope state.

Offset 0x238

The size of this region is 0x78-bytes. Initially this contains 0xFF/0x00 bytes.