Add CairoRunner functionality - WIP

pkg/vm/memory/memory.go

@@ -20,7 +20,7 @@ func (m *Memory) Insert(addr *Relocatable, val *MaybeRelocatable) error {
 	// FIXME: There should be a special handling if the key
 	// segment index is negative. This is an edge
 	// case, so for now let's raise an error.
-	if addr.segmentIndex < 0 {
+	if addr.SegmentIndex < 0 {
 		return errors.New("Segment index of key is negative - unimplemented")
 	}
 
@@ -61,7 +61,7 @@ func (m *Memory) Get(addr *Relocatable) (*MaybeRelocatable, error) {
 	// FIXME: There should be a special handling if the key
 	// segment index is negative. This is an edge
 	// case, so for now let's raise an error.
-	if addr.segmentIndex < 0 {
+	if addr.SegmentIndex < 0 {
 		return nil, errors.New("Segment index of key is negative - unimplemented")
 	}
 

pkg/vm/memory/relocatable.go

@@ -5,8 +5,8 @@ package memory
 // these values are replaced by real memory addresses,
 // represented by a field element.
 type Relocatable struct {
-	segmentIndex int
-	offset       uint
+	SegmentIndex int
+	Offset       uint
 }
 
 // Creates a new Relocatable struct with the specified segment index
@@ -18,12 +18,12 @@ func NewRelocatable(segment_idx int, offset uint) *Relocatable {
 // Get the the indexes of the Relocatable struct.
 // Returns a tuple with both values (segment_index, offset)
 func (r *Relocatable) into_indexes() (uint, uint) {
-	if r.segmentIndex < 0 {
-		corrected_segment_idx := uint(-(r.segmentIndex + 1))
-		return corrected_segment_idx, r.offset
+	if r.SegmentIndex < 0 {
+		corrected_segment_idx := uint(-(r.SegmentIndex + 1))
+		return corrected_segment_idx, r.Offset
 	}
 
-	return uint(r.segmentIndex), r.offset
+	return uint(r.SegmentIndex), r.Offset
 }
 
 // Int in the Cairo VM represents a value in memory that
@@ -47,6 +47,10 @@ func NewMaybeRelocatableInt(felt uint) *MaybeRelocatable {
 	return &MaybeRelocatable{inner: Int{felt}}
 }
 
+func NewMaybeRelocatableAddr(addr Relocatable) *MaybeRelocatable {
+	return &MaybeRelocatable{inner: addr}
+}
+
 // Creates a new MaybeRelocatable with a `nil` inner value
 func NewMaybeRelocatableNil() *MaybeRelocatable {
 	return &MaybeRelocatable{inner: nil}

pkg/vm/runner.go

@@ -22,10 +22,27 @@ func NewCairoRunner(program Program) *CairoRunner {
 	return &runner
 }
 
-// func (cr *CairoRunner) InitializeFunctionEntrypoint(vm *VirtualMachine, entrypoint uint, stack []memory.MaybeRelocatable, return_fp memory.MaybeRelocatable) (memory.Relocatable, error) {
-// 	finalPc := 
+func (cr *CairoRunner) InitializeFunctionEntrypoint(vm *VirtualMachine, entrypoint uint, stack []memory.MaybeRelocatable, returnFp memory.MaybeRelocatable) (*memory.Relocatable, error) {
+	finalPc := *vm.segments.Add()
+	stackExtension := []memory.MaybeRelocatable{returnFp, *memory.NewMaybeRelocatableAddr(finalPc)}
 
-// }
+	stack = append(stack, stackExtension...)
+
+	var relocatableNil memory.Relocatable
+	if cr.executionBase == relocatableNil {
+		return nil, errors.New("No execution base")
+	}
+
+	cr.initialFp = cr.executionBase.Offset + uint(len(stack))
+	cr.finalPc = finalPc
+
+	// err := cr.InitializeState(vm, entrypoint, stack)
+	// if err != nil {
+	// 	return nil, errors.New("Error initializing VM state: %s", err)
+	// }
+
+	return &finalPc, nil
+}
 
 func (cr *CairoRunner) InitializeMainEntrypoint(vm *VirtualMachine) (*memory.Relocatable, error) {
 	if &cr.entrypoint == nil {