OPCODE	DESCRIPTION
err	Fail immediately.
bnz target	branch to TARGET if value A is not zero
bz target	branch to TARGET if value A is zero
b target	branch unconditionally to TARGET
return	use A as success value; end
pop	discard A
popn n	remove N values from the top of the stack
dup	duplicate A
dup2	duplicate A and B
dupn n	duplicate A, N times
dig n	Nth value from the top of the stack. dig 0 is equivalent to dup
bury n	replace the Nth value from the top of the stack with A. bury 0 fails.
cover n	remove top of stack, and place it deeper in the stack such that N elements are above it. Fails if stack depth <= N.
uncover n	remove the value at depth N in the stack and shift above items down so the Nth deep value is on top of the stack. Fails if stack depth <= N.
frame_dig i	Nth (signed) value from the frame pointer.
frame_bury i	replace the Nth (signed) value from the frame pointer in the stack with A
swap	swaps A and B on stack
select	selects one of two values based on top-of-stack: B if C != 0, else A
assert	immediately fail unless A is a non-zero number
callsub target	branch unconditionally to TARGET, saving the next instruction on the call stack
proto a r	Prepare top call frame for a retsub that will assume A args and R return values.
retsub	pop the top instruction from the call stack and branch to it
switch target ...	branch to the Ath label. Continue at following instruction if index A exceeds the number of labels.
match target ...	given match cases from A[1] to A[N], branch to the Ith label where A[I] = B. Continue to the following instruction if no matches are found.