40 lines
1.7 KiB
Markdown
40 lines
1.7 KiB
Markdown
# TCPU
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Machine code interpreter written in pure C. Can execute programs up to 1 MEGABYTE (1048576 bytes) in size!!!
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## Building
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1. Install [cbuild](https://timerix.ddns.net:3322/Timerix/cbuild.git)
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2. Install [SDL3](https://github.com/libsdl-org/SDL) and [SDL3_image](https://github.com/libsdl-org/SDL_image) from package manager or source.
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3. ```sh
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cbuild build_exec_dbg
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```
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## Assembly language
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### Instructions
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| code | name | arguments | details |
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|------|------|-----------|---------|
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| 00 | NOP | | ignored instruction |
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| 01 | MOVC | `dst_register`, `value` | push constant value into `dst_register` |
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| 02 | MOVR | `dst_register`, `src_register` | copy value from `src_register` to `dst_register`
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| 03 | ADD | `dst_register`, `src_register` | `dst` += `src` |
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| 04 | SUB | `dst_register`, `src_register` | `dst` -= `src` |
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| 05 | MUL | `dst_register`, `src_register` | `dst` *= `src` |
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| 06 | DIV | `dst_register`, `src_register` | `dst` /= `src` |
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| 07 | MOD | `dst_register`, `src_register` | `dst` %= `src` |
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| 08 | SYS | | call system function |
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| 09 | EXIT | | stop the program with exit code in `ax` |
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### Registers
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| code | name | size (bits) |
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|------|------|-------------|
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| 01 | ax | 32 |
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| 02 | bx | 32 |
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| 03 | cx | 32 |
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| 04 | dx | 32 |
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### System functions
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To call a system function you need to push values to registers and write `SYS` opcode. The return value of a function will will be avaliable in `ax` after call.
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| `ax` | name | `bx` | `cx` | `dx` | details |
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|-----------|------|----|----|----|---------|
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| 0 | read | file number | buffer pointer | buffer size | read data from file |
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| 1 | write | file number | buffer pointer | buffer size | write data to file |
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