package j1 import ( "bytes" "encoding/binary" "fmt" "io/ioutil" ) type J1 struct { dsp uint16 // 5 bit Data stack pointer st0 uint16 // 5 bit Return stack pointer pc uint16 // 13 bit rsp uint16 // 5 bit dstack [0x20]uint16 // Data stack rstack [0x20]uint16 // Return stack memory [0x8000]uint16 } func (vm *J1) String() string { s := fmt.Sprintf("\tPC %0.4X\n", vm.pc) s += fmt.Sprintf("\tD %v %0.4X %0.4X\n", vm.dsp, vm.dstack[:vm.dsp], vm.st0) s += fmt.Sprintf("\tR %v %0.4X\n", vm.rsp, vm.rstack[:vm.rsp]) return s } func (vm *J1) LoadBytes(data []byte) error { size := len(data) >> 1 if size > len(vm.memory) { return fmt.Errorf("too big") } return binary.Read(bytes.NewReader(data), binary.BigEndian, vm.memory[:size]) } func (vm *J1) LoadFile(fname string) error { data, err := ioutil.ReadFile(fname) if err != nil { return err } return vm.LoadBytes(data) } func (vm *J1) Eval() { for { ins := Decode(vm.memory[vm.pc]) if ins == Jump(0) { break } vm.eval(ins) } } func (vm *J1) eval(ins Instruction) { next := vm.pc + 1 switch v := ins.(type) { case Lit: vm.st0 = uint16(v) vm.dstack[vm.dsp] = vm.st0 vm.dsp += 1 case Jump: next = uint16(v) case Cond: if vm.st0 == 0 { next = uint16(v) } vm.st0 = vm.dstack[vm.dsp] vm.dsp -= 1 case Call: vm.rstack[vm.rsp] = next vm.rsp += 1 next = uint16(v) case ALU: vm.dsp = uint16(int8(vm.dsp) + v.Ddir) vm.rsp = uint16(int8(vm.rsp) + v.Rdir) if v.NtoAtT { vm.memory[vm.st0] = vm.dstack[vm.dsp] } if v.TtoR { vm.rstack[vm.rsp] = vm.st0 } if v.TtoN { vm.dstack[vm.dsp] = vm.st0 } if v.RtoPC { next = vm.rstack[vm.rsp] } vm.st0 = vm.newST0(v) } vm.pc = next fmt.Println(ins) fmt.Println(vm) } func (vm *J1) newST0(v ALU) uint16 { T, N, R := vm.st0, vm.dstack[vm.dsp], vm.rstack[vm.rsp] switch v.Opcode { case 0: // T return T case 1: // N return N case 2: // T+N return T + N case 3: // T&N return T & N case 4: // T|N return T | N case 5: // T^N return T ^ N case 6: // ~T return ^T case 7: // N==T if N == T { return 1 } return 0 case 8: // N>T return N >> (T & 0xf) case 10: // T-1 return T - 1 case 11: // R (rT) return R case 12: // [T] return vm.memory[T] case 13: // N<