path: root/core/asm.go

package core

import (
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/vm"
)

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 := vm.OpCode(val)

        asm = append(asm, fmt.Sprintf("%04v: %v", pc, op))

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

            data := script[pc.Int64() : pc.Int64()+a]
            if len(data) == 0 {
                data = []byte{0}
            }
            asm = append(asm, fmt.Sprintf("%04v: 0x%x", pc, data))

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

        pc.Add(pc, common.Big1)
    }

    return asm
}