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

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 GPU 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	Input GPU framebuffer physical address>>3
0x1EF00C04	Output LCD framebuffer physical address>>3
0x1EF00C08	Output framebuffer dimensions, used with cmd3
0x1EF00C0C	Input framebuffer dimensions, used with cmd3
0x1EF00C10	Flags, 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. The dimensions fields seem to use the same format as LCD register 0x1EF00X5C. The input framebuffer width for the main screen is normally 480.

0x1EF00C10

Bit	Description
0	?
1	?
2	This bit is set when out-framebuf width/height is less than the input framebuf width/height, clear otherwise. Bit24 is normally clear when this bit is set.
4-3	?
11-5
12	Color format related?
23-13	?
24	When this is set, the actual output framebuffer width is width>>1.
31-25	?