vm: remove toPC parameter in Run method.

cmd/retro/main.go

@@ -103,7 +103,7 @@ func main() {
 	if err != nil {
 		return
 	}
-	err = proc.Run(len(proc.Image))
+	err = proc.Run()
 	// filter out EOF
 	if e := errors.Cause(err); e == io.EOF {
 		err = nil

vm/core.go

@@ -21,7 +21,7 @@ import "github.com/pkg/errors"
 // Opcode represents an Ngaro VM opcode.
 type Opcode Cell
 
-// ngaro Virtual Machine Opcodes.
+// Ngaro Virtual Machine Opcodes.
 const (
 	OpNop Opcode = iota
 	OpLit
@@ -82,13 +82,17 @@ func (i *Instance) Rpop() Cell {
 	return i.address[rsp]
 }
 
-// Run starts execution of the VM until the program pointer reaches `toPC`.
+// Run starts execution of the VM.
+//
 // If an error occurs, the PC will will point to the instruction that triggered
 // the error.
 //
 // If the VM was exited cleanly from a user program with the `bye` word, the PC
 // will be equal to len(i.Image) and err will be nil.
-func (i *Instance) Run(toPC int) (err error) {
+//
+// If the last input stream gets closed, the VM will exit and return io.EOF.
+// This is a normal exit condition in most use cases.
+func (i *Instance) Run() (err error) {
 	defer func() {
 		if e := recover(); e != nil {
 			var ok bool

vm/vm.go

@@ -18,7 +18,7 @@
 // TODO:
 //	- complete file i/o
 //	- add a reset func: clear stacks/reset ip to 0, accept Options (input / output may need to be reset as well)
-//	- add a disasm func
+//	- add a disassembly function.
 //	- go routines
 //	- BUG: I/O trashes ports in interactive mode. For example, the following returns 0 instead of the image size:
 //		-1 5 out 0 0 out wait 5 in putn
@@ -110,7 +110,7 @@ func InHandler(port Cell, handler IOCallback) Option {
 	}
 }
 
-// OutHandler will make any OUT on the given port call the provided hadler.
+// OutHandler will make any OUT on the given port call the provided handler.
 // The OUT value will be passed to the handler and the handler's return value
 // will be written to the port.
 func OutHandler(port Cell, handler IOCallback) Option {
@@ -120,12 +120,12 @@ func OutHandler(port Cell, handler IOCallback) Option {
 	}
 }
 
-// WaitHandler will make any WAIT on the given port call the provided hadler.
+// WaitHandler will make any WAIT on the given port call the provided handler.
 // The port value will be passed to the handler and the handler's return value
 // will be written to the port.
 //
 // The handler will only be called if port 0 value is 0 and if the bound port
-// value is != 0. Wait handlers can be used to override default port behaviour.
+// value is != 0. Wait handlers can be used to override default port behavior.
 // If the returned error is ErrUnhandled, the returned value and error will be
 // ignored, and the default implementation will handle the WAIT.
 func WaitHandler(port int, handler IOCallback) Option {
@@ -145,7 +145,7 @@ func (i *Instance) SetOptions(opts ...Option) error {
 	return nil
 }
 
-// Instance represents an ngaro VM instance.
+// Instance represents an Ngaro VM instance.
 type Instance struct {
 	PC        int
 	sp        int
@@ -191,7 +191,7 @@ func New(image Image, imageFile string, opts ...Option) (*Instance, error) {
 }
 
 // Data returns the data stack. Note that value changes will be reflected in the
-// instance's stack, but reslicing will not affect it. To add/remove values on
+// instance's stack, but re-slicing will not affect it. To add/remove values on
 // the data stack, use the Push and Pop functions.
 func (i *Instance) Data() []Cell {
 	if i.sp < len(i.data) {
@@ -201,7 +201,7 @@ func (i *Instance) Data() []Cell {
 }
 
 // Address returns the address stack. Note that value changes will be reflected
-// in the instance's stack, but reslicing will not affect it. To add/remove
+// in the instance's stack, but re-slicing will not affect it. To add/remove
 // values on the address stack, use the Rpush and Rpop functions.
 func (i *Instance) Address() []Cell {
 	if i.rsp < len(i.address) {

vm/vm_test.go

@@ -35,7 +35,7 @@ func setup(code, stack, rstack C) *vm.Instance {
 }
 
 func check(t *testing.T, i *vm.Instance, ip int, stack C, rstack C) {
-	err := i.Run(len(i.Image))
+	err := i.Run()
 	if err != nil {
 		t.Errorf("%+v", err)
 		return
@@ -138,7 +138,7 @@ func ExampleInstance_Run() {
 
 	// run it
 	if err == nil {
-		err = i.Run(len(i.Image))
+		err = i.Run()
 	}
 	if err != nil {
 		// in interactive use, err may be io.EOF if any of the IO channels gets closed
@@ -181,7 +181,7 @@ func ExampleOutHandler() {
 		panic(err)
 	}
 
-	if err = i.Run(len(i.Image)); err != nil && errors.Cause(err) != io.EOF {
+	if err = i.Run(); err != nil && errors.Cause(err) != io.EOF {
 		fmt.Fprintf(os.Stderr, "%+v\n", err)
 	}
 	// Retro 11.7.1
@@ -260,7 +260,7 @@ func Test_Fib_RetroLoop(t *testing.T) {
 	img, _ := vm.Load(imageFile, 50000)
 	i, _ := vm.New(img, imageFile,
 		vm.Input(strings.NewReader(fib)))
-	i.Run(len(i.Image))
+	i.Run()
 	for c := len(i.Address()); c > 0; c-- {
 		i.Rpop()
 	}
@@ -275,7 +275,7 @@ func Benchmark_Fib_AsmLoop(b *testing.B) {
 	i := setup(f, C{35}, nil)
 	for c := 0; c < b.N; c++ {
 		i.PC = 0
-		i.Run(len(i.Image))
+		i.Run()
 		i.Pop()
 		i.Push(35)
 	}
@@ -289,7 +289,7 @@ func Benchmark_Fib_AsmRecursive(b *testing.B) {
 	i := setup(f, C{35}, nil)
 	for c := 0; c < b.N; c++ {
 		i.PC = 0
-		i.Run(len(i.Image))
+		i.Run()
 		i.Pop()
 		i.Push(35)
 	}
@@ -303,7 +303,7 @@ func Benchmark_Fib_RetroLoop(b *testing.B) {
 		i, _ := vm.New(img, imageFile,
 			vm.Input(strings.NewReader(fib)))
 		b.StartTimer()
-		i.Run(len(i.Image))
+		i.Run()
 	}
 }
 
@@ -315,7 +315,7 @@ func Benchmark_Fib_RetroRecursive(b *testing.B) {
 		i, _ := vm.New(img, imageFile,
 			vm.Input(strings.NewReader(fib)))
 		b.StartTimer()
-		i.Run(len(i.Image))
+		i.Run()
 	}
 }
 
@@ -342,7 +342,7 @@ func BenchmarkRun(b *testing.B) {
 		n := time.Now()
 		b.StartTimer()
 
-		err = proc.Run(len(proc.Image))
+		err = proc.Run()
 
 		b.StopTimer()
 		el := time.Now().Sub(n).Seconds()