VM ARC

3 files changed, 94 insertions, 0 deletions

diff --git a/pkg/lang/vm/mem/cell.go b/pkg/lang/vm/mem/cell.go
new file mode 100644
index 0000000..044a45c
--- /dev/null
+++ b/pkg/lang/vm/mem/cell.go
@@ -0,0 +1,16 @@
+package mem
+
+type CellKind int
+
+const (
+	CellKindEmpty CellKind = iota
+	CellKindString
+	CellKindArray
+	CellKindEscaped
+)
+
+type cell struct {
+	kind CellKind
+	refs int
+	data any
+}
diff --git a/pkg/lang/vm/mem/mem.go b/pkg/lang/vm/mem/mem.go
new file mode 100644
index 0000000..4335347
--- /dev/null
+++ b/pkg/lang/vm/mem/mem.go
@@ -0,0 +1,68 @@
+package mem
+
+type Mem struct {
+	cells []cell
+	free  []int
+}
+
+func New() Mem {
+	return Mem{
+		cells: make([]cell, 0),
+		free:  make([]int, 0),
+	}
+}
+
+func (m *Mem) Allocate(kind CellKind) Ptr {
+	if len(m.free) > 0 {
+		idx := m.free[len(m.free)-1]
+		m.free = m.free[:len(m.free)-1]
+
+		if m.cells[idx].kind != CellKindEmpty {
+			panic("invalid free cell")
+		}
+
+		m.cells[idx].kind = kind
+		return Ptr(idx)
+	} else {
+		idx := len(m.cells)
+		m.cells = append(m.cells, cell{kind: kind})
+		return Ptr(idx)
+	}
+
+}
+
+func (m *Mem) Set(ptr Ptr, v any) {
+	if ptr >= Ptr(len(m.cells)) {
+		panic("out of bounds")
+	}
+
+	m.cells[ptr].data = v
+}
+
+func (m *Mem) Get(ptr Ptr) any {
+	if ptr >= Ptr(len(m.cells)) {
+		panic("out of bounds")
+	}
+
+	return m.cells[ptr].data
+}
+
+func (m *Mem) Retain(ptr Ptr) {
+	if ptr >= Ptr(len(m.cells)) {
+		panic("out of bounds")
+	}
+
+	m.cells[ptr].refs++
+}
+
+func (m *Mem) Release(ptr Ptr) {
+	if ptr >= Ptr(len(m.cells)) {
+		panic("out of bounds")
+	}
+
+	m.cells[ptr].refs--
+	if m.cells[ptr].refs == 0 {
+		m.cells[ptr].kind = CellKindEmpty
+		m.free = append(m.free, int(ptr))
+	}
+}
diff --git a/pkg/lang/vm/mem/ptr.go b/pkg/lang/vm/mem/ptr.go
new file mode 100644
index 0000000..5e3bf3d
--- /dev/null
+++ b/pkg/lang/vm/mem/ptr.go
@@ -0,0 +1,10 @@
+package mem
+
+import "strconv"
+
+type Ptr uint64
+
+func (p Ptr) String() string {
+	val := strconv.FormatUint(uint64(p), 10)
+	return "@" + val
+}