BIP MergedMiningScript

• <Block header is on stack>
• OP_SHA256d
• PUSH...: various other merged chains as merkle links
• PUSH: N of merkle links
• OP_MERKLEROOT_FROMLINKS

Inside parent chain coinbase:

• PUSH: coinbase prefix midstate
• OP_SWAP
• OP_SHA256FINISH
• OP_SHA256 (to get a SHA256d result; the parent chain coinbase's txid)
• PUSH...: various other transactions in parent chain (as merkle links)
• PUSH: N of merkle links
• OP_MERKLEROOT_FROMLINKS (stack now has the parent chain tx merkleroot)
• PREPEND: parent chain version
• APPEND: parent chain header ending
• OP_SHA256d (stack now has the proof-of-work)

Dedicated merged mining:

• APPEND: 16-bit time offset
• APPEND: 48-bit nonce
• OP_SHA256d