VTL
VTL is an esoteric programming language created by user:David.werecat which loads code into modifiable memory and an extended section.
Instructions
Each instruction is split into two parts, the OpCode and the Param. The OpCode is the first three bits of the instruction, and the Param is the other 5 bits. Code is executed in a 256 byte long segment. There is a pointer register that points into that segment. The current "value" is the instruction pointed to by the pointer register. If a second file is specified to the interpreter, it is loaded into the extended section. The extended section can be any size. When execution flow jumps to the extended section, the pointer register still indexes the code segment. When the execution reaches the end of the code segment or extended section, it loops back to the start. Possible OpCodes are as follows:
| OpCode | Description |
|---|---|
000 |
Move the pointer register forward by Param |
001 |
Move the pointer register backward by Param |
010 |
Increment the value by Param |
011 |
Decrement the value by Param |
100 |
Jump forward Param+1 instructions if the value is 0 |
101 |
Jump forward Param+1 instructions if the value is not 0 |
110 |
Execute an extended instruction specified by Param |
111 |
Terminate the program with exit status Param |
Extended Instructions are as follows:
| Param | Description |
|---|---|
00000 |
Clear the console |
00001 |
Beep |
00010 |
Set the value to random |
00011 |
Read a character from the console into value |
00100 |
Write a character from value to the console |
00101 |
Push the value into stack 1 |
00110 |
Push the value into stack 2 |
00111 |
Pop the value from stack 1 |
01000 |
Pop the value from stack 2 |
01001 |
Set the value to the value pointed to by value |
01010 |
Set the value to 0 |
01011 |
Binary not on value |
01100 |
Jump to the extender grid |
01101 |
Return from the extender grid |
01110 |
Start executing instructions |
01111 |
Stop executing instructions |
1xxxx |
Waits for 2^xxxx miliseconds |