https://github.com/crazypython/wentelx87
Wentel is a machine code language.
https://github.com/crazypython/wentelx87
Last synced: about 1 month ago
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Wentel is a machine code language.
- Host: GitHub
- URL: https://github.com/crazypython/wentelx87
- Owner: CrazyPython
- Created: 2016-10-09T17:29:58.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2016-10-10T01:40:00.000Z (over 8 years ago)
- Last Synced: 2025-02-17T23:49:01.441Z (4 months ago)
- Language: Python
- Size: 10.7 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# wentelx87
Wentel consists of, at the basic level, a memory pointer and an instruction pointer. Instructions are stored loaded into memory. The execution pointer moves to the right after executing the instruction at that memory pointer.
The program is loaded into rightmost slot of memory. For example, if your program is `0010 0000 0101 0100`,
then the virtual machine will look like this when started:
```
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0010 0000 0101 0100 (memory)
^ (execution pointer)
^ (memory pointer)
```
## Opcodes
*Note:* This Wentel Virtual Machine is 8 bit. That is, memory pointers are 8 bits long. Each memory register holds four bits of information. These instructions can be modified to adjust the memory table size.
*Note 2:* "Word size" means the size of the memory address in bits. This implementation's word size is 8.
**`0000`** - no-op
**`0001`** - if the current address's value is equal to the value stored by the adress defined by the next word, move the execution pointer to the address pointed to the next word after the word after the current address.
**`0010`** - move memory pointer to address specified by next word.
**`0011`** - deposit the current address of the execution pointer into the current memory address
**`0100`** - increment current memory address
**`0101`** - decrement current memory address
**`0110`** - move memory pointer left
**`0111`** - move memory pointer right
Invalid opcodes cause undefined behavior.
## Output
*Note:* Output is not a part of the barebones Wentel specification. Output is instead an
extension that exploits the unused opcodes in the barebones Wentel specification.
Output is defined by special opcodes. All **`1XXX`** opcodes maniuplate external resources.
**`1000`** - output `0`
**`1001`** - output `1`
In this implementation of the Wentel Virtual Machine,
every 8 bits it will decode the last 8 bits and output them as ASCII. Escape characters are supported.
## Usage
Run `python3 main.py`. The options are:
- no options - will read instructions from stdin until linebreak
- with file name - read instructions from file
- `-d` - activate debugging mode, steps through memory, showing execution + memory pointers (don't forget `-i`)
- `-i` - interactive mode - explicitly tell to read instructions from stdin.
To make debugging mode more useful, change `2 ** 8` in the code to a smaller value that still fits your program, like `2**5`.
## Examples
*Spaces were added to help reading. The Wentel Virtual Machine does not accept spaces.*
`0001 1111 1111 0000 1000` - this snippet will move the execution pointer to `0000 1000` if the curent value is equal to the value pointed to by `1111 1111`