path: root/vm/asm.go

package vm

import (
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/ethutil"
)

func Disassemble(script []byte) (asm []string) {
    pc := new(big.Int)
    for {
        if pc.Cmp(big.NewInt(int64(len(script)))) >= 0 {
            return
        }

        // Get the memory location of pc
        val := script[pc.Int64()]
        // Get the opcode (it must be an opcode!)
        op := OpCode(val)

        asm = append(asm, fmt.Sprintf("%v", op))

        switch op {
        case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8, PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16, PUSH17, PUSH18, PUSH19, PUSH20, PUSH21, PUSH22, PUSH23, PUSH24, PUSH25, PUSH26, PUSH27, PUSH28, PUSH29, PUSH30, PUSH31, PUSH32:
            pc.Add(pc, ethutil.Big1)
            a := int64(op) - int64(PUSH1) + 1
            if int(pc.Int64()+a) > len(script) {
                return nil
            }

            data := script[pc.Int64() : pc.Int64()+a]
            if len(data) == 0 {
                data = []byte{0}
            }
            asm = append(asm, fmt.Sprintf("0x%x", data))

            pc.Add(pc, big.NewInt(a-1))
        }

        pc.Add(pc, ethutil.Big1)
    }

    return
}