| 202 | } |
| 203 | |
| 204 | func opPick(vm *virtualMachine) error { |
| 205 | err := vm.applyCost(2) |
| 206 | if err != nil { |
| 207 | return err |
| 208 | } |
| 209 | n, err := vm.popInt64(false) |
| 210 | if err != nil { |
| 211 | return err |
| 212 | } |
| 213 | if n < 0 { |
| 214 | return ErrBadValue |
| 215 | } |
| 216 | off, ok := checked.AddInt64(n, 1) |
| 217 | if !ok { |
| 218 | return ErrBadValue |
| 219 | } |
| 220 | if int64(len(vm.dataStack)) < off { |
| 221 | return ErrDataStackUnderflow |
| 222 | } |
| 223 | err = vm.push(vm.dataStack[int64(len(vm.dataStack))-(off)], false) |
| 224 | if err != nil { |
| 225 | return err |
| 226 | } |
| 227 | return nil |
| 228 | } |
| 229 | |
| 230 | func opRoll(vm *virtualMachine) error { |
| 231 | err := vm.applyCost(2) |