OP_SUB performs a subtraction operation between the top two items on the stack. It pops these two items, subtracts the top item from the second-to-top item, and pushes the result back onto the stack. This opcode is essential in scripts that involve arithmetic calculations, particularly where differences between values are required.
OP_Code Walkthrough
Subtracts the second item from the top item of the stack
Pop Top Item a
Pop Top Item b
Subtract a from b
Push Result