dolphin_write8
Write a single byte (0-255) to PowerPC memory at a given address for cheat codes, debug pokes, and game-state mutations. The write takes effect immediately.
Instructions
PURPOSE: Write a single unsigned byte (0-255) to PowerPC memory at the given absolute address. USAGE: Use for single-byte cheats, debug pokes, and game-state mutations. For 16/32/64-bit values prefer dolphin_write16/write32/write64 (atomic from the game's perspective). To roll back, dolphin_save_state BEFORE the write and dolphin_load_state to restore. BEHAVIOR: DESTRUCTIVE: overwrites with no undo. Direct memory access — bypasses PowerPC MMU translation and any DMA semantics. Writes to read-only regions (boot ROM at 0xFFF00000, certain I/O ranges) are silently dropped by Dolphin. The write takes effect immediately, but visible effects appear only when the emulator next ticks. No alignment requirement for byte access.
GameCube + Wii main address space landmarks (PowerPC, big-endian): 0x80000000-0x817FFFFF MEM1 main RAM (24 MiB) — GameCube + Wii game code & data GameCube games stay entirely within MEM1. Wii games use MEM1 for code and frequently-accessed data. 0x80000020 OS_GLOBALS — game-info struct (disc ID, FST, etc.) 0x80000034 OS_ARENA_LO (start of free MEM1 heap) 0x80003100 OS_REPORT (developer-console mirror, varies by SDK) 0x90000000-0x93FFFFFF MEM2 (64 MiB) — Wii ONLY. Larger texture/asset data, IOS work areas. Reading MEM2 on a GameCube game returns garbage / FAIL. 0xCC000000-0xCC00FFFF Hollywood I/O (Wii) / Flipper I/O (GameCube) — DMA, GPU FIFO, AI, EXI registers. Reads are usually safe, writes can wedge the emulator. Avoid. 0xCD000000-0xCD007FFF Wii-only Hollywood registers.
Notes: • All multi-byte values are BIG-ENDIAN on the real hardware. Felk's memory.read_u*/write_u* helpers handle the byte swap for you — the value you see is the value the game sees as a u32. • Addresses are 32-bit; Felk truncates the high bits of any u64 address argument. • Pointers in MEM1 are often stored as 4-byte addresses with the high bit set (e.g. 0x81234567). Dereferencing them requires no masking — pass the raw value back into memory.read_*.
RETURNS: 'Wrote VAL_DEC (0xVAL_HEX) → ADDR_HEX'.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| address | Yes | Absolute PowerPC virtual address (0x80000000-0x9FFFFFFF). Pass as a number; hex literals like 0x80001000 are fine. Reads 1 consecutive byte starting here and interprets them as a big-endian value. No alignment requirement for byte access. Useful ranges: 0x80000000-0x817FFFFF for MEM1 (GC + Wii), 0x90000000-0x93FFFFFF for MEM2 (Wii only). | |
| value | Yes | Byte value (0-255 / 0x00-0xFF). |
Implementation Reference
- bridge/mcp_bridge.py:141-141 (registration)Bridge-side dispatch table entry mapping "memory.write_u8" to the _write_u8 handler function.
"memory.write_u8": _write_u8,