Description:

Pop the top byte off of the stack and divide the new top byte by the old top byte.  Replace the new top byte with the remainder of the division result.

Pseudo Code:

stack[sp - 2] = stack[sp - 2] % stack[sp - 1]
sp = sp - 1
pc = pc + 1

Flags Affected:

D	H	C	Z	N

Possible Errors:

tvmStackUnderflow	-	There were not enough bytes in the stack.
tvmDivideByZero	-	Division by Zero is illegal.

Example:

modb

Before stack   top 1 0x05 2 0x39   bottom

After stack   top 1 0x02   bottom