Opcodes · arithmetic · enabled

OP_LESSTHAN (0x9f)

Pushes 1 if a is less than b, otherwise 0. Since May 2025 numbers may be up to 10,000 bytes long (BigInt).

Verified
Stack in → out
a b → a<b
Since
Original Bitcoin script
Cost
Base instruction cost 100 plus the byte length of the pushed result (2025 VM limits).
Bitcoin status
Same in Bitcoin (BTC)BTC limits arithmetic inputs to 4 bytes.

Example

OP_2 OP_3 OP_LESSTHAN

Step through it opcode by opcode in Bitauth IDE, the in-browser BCH VM debugger.

Sources

  1. Libauth BCH_2023_05 opcodes (bch-2023-opcodes.ts)
  2. CHIP-2021-05 VM Limits: Targeted Virtual Machine Limits
  3. CHIP-2024-07 BigInt: High-Precision Arithmetic