GPU/External Registers

Map

0x1EF00400 is the top screen
0x1EF00500 is the bottom screen

Init Values from nngxInitialize for Top Screen

0x1EF00400 = 0x1C2
0x1EF00404 = 0xD1
0x1EF00408 = 0x1C1
0x1EF0040C = 0x1C1
0x1EF00410 = 0
0x1EF00414 = 0xCF
0x1EF00418 = 0xD1
0x1EF0041C = 0x1C501C1
0x1EF00420 = 0x10000
0x1EF00424 = 0x19D
0x1EF00428 = 2
0x1EF0042C = 0x1C2
0x1EF00430 = 0x1C2
0x1EF00434 = 0x1C2
0x1EF00438 = 1
0x1EF0043C = 2
0x1EF00440 = 0x1960192
0x1EF00444 = 0
0x1EF00448 = 0
0x1EF0045C = 0x19000F0
0x1EF00460 = 0x1c100d1
0x1EF00464 = 0x1920002
0x1EF00470 = 0x80340
0x1EF0049C = 0

More Init Values from nngxInitialize for Top Screen

0x1EF00468 = 0x18300000, later changed by GSP module when updating state, framebuffer
0x1EF0046C = 0x18300000, later changed by GSP module when updating state, framebuffer
0x1EF00494 = 0x18300000
0x1EF00498 = 0x18300000
0x1EF00478 = 1, doesn't stay 1, read as 0
0x1EF00474 = 0x10501

This register controls how the LCD framebuffer is displayed.

0x1EF018E0

Register address	Description
0x1EF018E0	Buffer Size>>3
0x1EF018E8	Buffer physical address>>3
0x1EF018F0	Writing value 1 here triggers GPU processing for the specified buffer

These 3 registers are used by GX command 1. This is used for OpenGL commands.

0x1EF00010

Register address	Description
0x1EF000X0	Buffer physical address>>3
0x1EF000X4	Associated buffer physical address>>3
0x1EF000X8	Buffer size
0x1EF000XC	The low u16 for this register is overwritten by the GX command u16 parameter

These registers are used by GX command 2. 0x1EF00010 is used for the GX command buf0 parameters, while 0x1EF00020 is used for the GX command buf1 parameters.

0x1EF00C00

Register address	Description
0x1EF00C00	VRAM framebuffer physical address>>3
0x1EF00C04	Output framebuffer physical address>>3
0x1EF00C08	Output framebuffer dimensions, used with cmd3
0x1EF00C0C	VRAM framebuffer dimensions, used with cmd3
0x1EF00C10	Unknown, used with cmd3 and cmd4
0x1EF00C14	GSP module writes value 0 here prior to writing to 0x1EF00C18, for cmd3
0x1EF00C18	Writing value 1 here triggers GPU processing for the specified buffers
0x1EF00C20	Unknown, used with cmd4
0x1EF00C24	Unknown, used with cmd4
0x1EF00C28	Unknown, used with cmd4

These registers are used by GX command 3 and 4. For cmd4, *0x1EF00C18 |= 1 is used instead of just writing value 1.

GPU Commands

The buffer for GX command 1 with the registers at 0x1EF018E0 is used for GPU commands including OpenGL commands, each 8-byte entry in the buffer is a command. Cmd+0 is the command parameter, and cmd+4 is the cmdID.

Commands

CommandID	Parameter	Description
0x000F0010	Value is 0x12345678	This command is always the last command in the buffer.
0x000F0110	Value 0x1	This command is immediately before CmdID 0x000F0010, this is used elsewhere in the buffer as well.
0x000F0111	Value 0x1	This command is immediately before CmdID 0x000F0110, however CmdID 0x000F0110 doesn't always follow this command.
0x000F0042	float y vector	This sets Y scaling for the current matrix.
0x000F0044	float x vector	This sets X scaling for the current matrix.
0x000F02C0	Some ID?	This is used immediately before CmdID 0x00FF02C1.
0x00FF02C1	float	The input parameter and the float data following this command seems to be used for vertices.