restructure project

internal/vm/frame.go

@@ -0,0 +1,46 @@
+package vm
+
+import (
+	"monkey/internal/code"
+	"monkey/internal/object"
+	"unsafe"
+)
+
+var cache = NewFrameCache(32)
+
+type Frame struct {
+	cl          *object.Closure
+	ip          int
+	basePointer int
+}
+
+func NewFrame(cl *object.Closure, basePointer int) *Frame {
+	key := uint(uintptr(unsafe.Pointer(cl))) + uint(basePointer)
+	if frame, ok := cache.Get(key); ok {
+		frame.Reset()
+		return frame
+	}
+
+	frame := &Frame{
+		cl:          cl,
+		ip:          -1,
+		basePointer: basePointer,
+	}
+
+	cache.Put(key, frame)
+
+	return frame
+}
+
+// NextOp ...
+func (f *Frame) NextOp() code.Opcode {
+	return code.Opcode(f.Instructions()[f.ip+1])
+}
+
+func (f *Frame) Reset() {
+	f.ip = -1
+}
+
+func (f *Frame) Instructions() code.Instructions {
+	return f.cl.Fn.Instructions
+}