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UniCHIP8 Programming
UniCHIP8 uses the command and message patterns to enable communications between one or more virtual machines and your scene.
- The UniCHIP8Router component operates as a simple text-based message broker; it maintains a registry of connected nodes
- The UniCHIP8Node component connects it's attached GameObject to a UniCHIP8Router and processes messages
- The UniCHIP8 component is the CHIP-8 virtual machine itself; it inherits from UniCHIP8Node and attaches to a router
UniCHIP8 extended opcodes require that the I register be set to the starting address of a string, the name of a Unity GameObject, prior to being called.
Several UniCHIP8 extended opcodes require values be set in registers V0-V3 prior to be being called.
UniCHIP8 strings are null-terminated and must not be greater than 32 characters.
All numbers (aside from address pointers) in UniCHIP8 are represented by bytes (the set of positive integers from 0 to 255). There are no negative values.
When using the rotate* opcodes, byte value(s) will be scaled such that the value 0xFF (255) represents 360 degrees.
When using the setMaterialColor or setLightColor opcodes, byte value(s) will be normalized to floats in the range of 0f to 1f.
| hex (dec) | description |
|---|---|
| 0x0000 (0000) | CHIP-8 reserved space starts; interrupt table starts |
| 0x001F (0031) | Interrupt table ends |
| 0x0020 (0032) | Interrupt data starts |
| 0x005F (0095) | Interrupt data ends |
| ... | |
| 0x01FF (0511) | CHIP-8 reserved space ends |
| 0x0200 (0512) | Boot address |
| ... | |
| 0x0D50 (3408) | Data port starts |
| 0x0D6F (3440) | Data port ends |
| ... | |
| 0x0D7F (3455) | CHIP-8 font data starts |
| 0x0DCF (3535) | CHIP-8 font data ends |
| ... | |
| 0x0FFF (4095) | End of RAM |
When not in strict CHIP-8 compatibility mode, the first 96 bytes of RAM are reserved for interrupt processing.
Each entry in the interrupt table is 2 bytes long and contains a pointer to a subroutine, the interrupt handler, that should be executed when the interrupt is triggered.
Interrupt handlers should cache register state on entry and restore on exit.
The interrupt table is followed by 64 bytes of space reserved for data passed from the Unity scene for the interrupt handler to process.
| ID | Pointer | Name |
|---|---|---|
| 0 | 0x0000 | collision |
| 1 | 0x0002 | data port |
| 2 | 0x0004 | |
| 3 | 0x0006 | |
| 4 | 0x0008 | |
| 5 | 0x000A | |
| 6 | 0x000C | |
| 7 | 0x000E | |
| 8 | 0x0010 | |
| 9 | 0x0012 | |
| 10 | 0x0014 | |
| 11 | 0x0016 | |
| 12 | 0x0018 | |
| 13 | 0x001A | |
| 14 | 0x001C | |
| 15 | 0x001E |
| extension | file type |
|---|---|
| filename.ch8 | CHIP-8 rom |
| filename.uc8 | UniCHIP8 rom |
| filename.8o | Octo CHIP-8 rom source |
| filename.u8o | Octo UniCHIP8 rom source |
- Modified Octo compiler for UniCHIP8
- UniCHIP8 Tools