Rover Web Interface

Rover runs programs made of bytes (and each byte is a number between 0 and 255). We describe those bytes with hex, where each byte is written as two characters:

• 0 becomes 00
• 1 becomes 01
• 186 becomes BA, because 186₁₀ = BA₁₆

The Rover expects its programs to start with a short signature that says "I am a rover program": the four characters MVM1 (what are their bytes?). After that, the rest of the bytes describe what to do.

You can type your program in the box below. Spaces and newlines do not matter, so both of these programs are identical:

4D564D31 01000059
4D 56 4D 31 01 00 00 59

When you click Run, you’ll see three steps update above the results:

• Decoding: we decode your input into actual bytes.
• Parsing: we check the program structure and understand the instructions.
• Running: we execute the program and show its output and stack.

1) Small program which does nothing and exits:

4D564D3101000059

2) Add two numbers (2 + 3) and print the result — you should see 5 in "Program output":

4D564D310E00011002000000100300000058016059060200200020013059

• Hex is not case-sensitive: aa is the same as AA.
• Every byte must be two hex characters. If you type a single character like A, the decoder will complain.
• Make sure your program starts with MVM1. If not, parsing will fail.
• For more details, it could be worth opening the "Raw response from the server" panel at the bottom to see details.