Utility ROM to change the main memory of SNES to any value and pass the value to other games.
By using DMA registers as general-purpose RAM, it operates without overwriting the main memory.
Assemble using asar.
asar Main.asm RamEdit.sfcbuild.bat is available for windows.
Burn to 512 KiB ROM cartridge.
Flash cartridges such as FXPAK can also be used, but some initial values in memory will be overwritten by the firmware.
| Key | Description |
|---|---|
| D-Pad | Move cursor |
| A | Increment the value at the cursor position |
| B | Decrement the value at the cursor position |
| X | Copy nibble at cursor position |
| Y | Pastes the copied nibble at the cursor position |
| L | Move to previous page |
| R | Move to next page |
| Start | Open menu |
| Select | Open jump address |
| Key | Description |
|---|---|
| D-Pad Up | Move cursor up |
| D-Pad Down | Move cursor down |
| A | Confirm |
| B | Cancel (close menu) |
| Start | Cancel (close menu) |
Fill page (64 bytes) with value at cursor position.
Fill all memory (0x20000 bytes) with the value at the cursor position.
Initialize to a pre-defined value.
See also the Preset memory section below.
Execute the cursor position as the program start address.
The registers are initialized with the following values.
| Register | Value |
|---|---|
| A | $0000 (8bit) |
| X | $0000 (8bit) |
| Y | $0000 (8bit) |
| SP | $01FC (return address is pushed) |
| P | $36 (nvMXdIZc e) |
| D | $0000 |
| DB | $7E or $7F (cursor bank) |
| PB | $7E or $7F (cursor bank) |
| PC | (cursor address) |
Use RTL instruction ($6B) to end execution.
If the BRK ($00) or COP ($02) instruction is executed and a certain amount of time is exceeded,
it will be halted.
Jump the address in units larger than the edit screen.
| Key | Description |
|---|---|
| D-Pad Left | Move cursor left (backward 0x400 bytes) |
| D-Pad Right | Move cursor right (forward 0x400 bytes) |
| A | Confirm |
| B | Cancel (back to edit) |
| Select | Cancel (back to edit) |
It has 3 presets that can initialize memory to specific values.
Create PresetMemory/blabla.asm file and edit PresetMemory.asm file.
Or edit the RamEdit.sfc file directly. (Slot1: 0x20000-0x3FFFF, Slot2: 0x40000-0x5FFFF, Slot3: 0x60000-0x7FFFF)
As a sample, memory definition is set in slot 1 to enable SMB3 debug flag for the Super Mario All-Stars.
- Embedded assembler?
Removing and inserting the cassette while the power is on may damage the SNES main unit.
Use at your own risk.