OP_2SWAP

INFO

Opcode number: 114
Byte representation: 0x72
Short description: Swap the top two pairs of stack items.

OP_2SWAP is used to swap the top two pairs of items on the stack. The first and second stack items are swapped with the third and fourth items.

Operation

1. Swap the top two items with the third and fourth items on the stack, preserving the order of each pair.

Notes

• This opcode works with pairs of stack items. If there are fewer than four items on the stack when OP_2SWAP is executed, the script will fail.
• OP_SWAP is a related opcode for swapping just the top two items.

Examples

Example 1

Swapping the top two pairs with six total items:

# ASM script
OP_1 OP_2 OP_3 OP_4 OP_5 OP_6 OP_2SWAP

# Raw script
51525354555672

# Stack (before OP_2SWAP)
6  # top
5
4
3
2
1

# Stack (after OP_2SWAP)
4
3
6
5
2
1