From c2d4bf51de9a2d721168c62b14b89f5281ed366e Mon Sep 17 00:00:00 2001
From: Mel <einebeere@gmail.com>
Date: Fri, 27 May 2022 00:09:27 +0000
Subject: VM ARC

---
 pkg/lang/vm/mem/mem.go | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 pkg/lang/vm/mem/mem.go

(limited to 'pkg/lang/vm/mem/mem.go')

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))
+	}
+}
-- 
cgit 1.4.1