Befunge-93 instruction list
0-9 Push this number on the stack
+ Addition: Pop a and b, then push a+b
- Subtraction: Pop a and b, then push b-a
* Multiplication: Pop a and b, then push a*b
/ Integer division: Pop a and b, then push b/a, rounded down. If a is zero, ask the user what result they want.
% Modulo: Pop a and b, then push the remainder of the integer division of b/a. If a is zero, ask the user what result they want.
! Logical NOT: Pop a value. If the value is zero, push 1; otherwise, push zero.
` Greater than: Pop a and b, then push 1 if b>a, otherwise zero.
> Start moving right
< Start moving left
^ Start moving up
v Start moving down
? Start moving in a random cardinal direction
_ Pop a value; move right if value=0, left otherwise
| Pop a value; move down if value=0, up otherwise
" Start string mode: push each character's ASCII value all the way up to the next "
: Duplicate value on top of the stack
\ Swap two values on top of the stack
$ Pop value from the stack
. Pop value and output as an integer
, Pop value and output as ASCII character
# Trampoline: Skip next cell
p A "put" call (a way to store a value for later use). Pop y, x and v, then change the character at the position (x,y) in the program to the character with ASCII value v
g A "get" call (a way to retrieve data in storage). Pop y and x, then push ASCII value of the character at that position in the program
& Ask user for a number and push it
~ Ask user for a character and push its ASCII value
@ End program