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refactor: using a simple array for stack

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This commit is contained in:
Patrick MARIE 2024-08-28 08:58:48 +02:00
parent eb265777d9
commit f7c10c13bb
1 changed files with 15 additions and 12 deletions
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27
src/vm.zig
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@ -27,7 +27,8 @@ pub const VM = struct {
allocator: Allocator, allocator: Allocator,
chunk: ?*Chunk, chunk: ?*Chunk,
ip: ?usize, ip: ?usize,
stack: std.ArrayList(Value), stack: [constants.STACK_MAX]Value,
stack_top: usize,
// Keeping creating objects in references to destroy objects on cleaning. // Keeping creating objects in references to destroy objects on cleaning.
// In the book, a linked list between objects is used to handle this. // In the book, a linked list between objects is used to handle this.
references: std.ArrayList(*Obj), references: std.ArrayList(*Obj),
@ -40,7 +41,8 @@ pub const VM = struct {
.allocator = allocator, .allocator = allocator,
.chunk = null, .chunk = null,
.ip = null, .ip = null,
.stack = std.ArrayList(Value).init(allocator), .stack = undefined,
.stack_top = 0,
.references = std.ArrayList(*Obj).init(allocator), .references = std.ArrayList(*Obj).init(allocator),
.strings = Table.new(allocator), .strings = Table.new(allocator),
.globals = Table.new(allocator), .globals = Table.new(allocator),
@ -49,8 +51,6 @@ pub const VM = struct {
} }
pub fn free(self: *VM) void { pub fn free(self: *VM) void {
self.stack.deinit();
if (self.has_tracing()) { if (self.has_tracing()) {
self.strings.dump(); self.strings.dump();
} }
@ -87,11 +87,11 @@ pub const VM = struct {
pub fn run(self: *VM) !InterpretResult { pub fn run(self: *VM) !InterpretResult {
while (true) { while (true) {
if (self.has_tracing()) { if (self.has_tracing()) {
if (self.stack.items.len > 0) { if (self.stack_top > 0) {
debug.print("{s:32}", .{""}); debug.print("{s:32}", .{""});
for (self.stack.items) |item| { for (0..self.stack_top) |item_idx| {
debug.print("[ ", .{}); debug.print("[ ", .{});
print_value(item); print_value(self.stack[item_idx]);
debug.print(" ]", .{}); debug.print(" ]", .{});
} }
debug.print("\n", .{}); debug.print("\n", .{});
@ -176,11 +176,11 @@ pub const VM = struct {
}, },
@intFromEnum(OpCode.OP_GET_LOCAL) => { @intFromEnum(OpCode.OP_GET_LOCAL) => {
const slot = self.read_byte(); const slot = self.read_byte();
try self.push(self.stack.items[slot]); try self.push(self.stack[slot]);
}, },
@intFromEnum(OpCode.OP_SET_LOCAL) => { @intFromEnum(OpCode.OP_SET_LOCAL) => {
const slot = self.read_byte(); const slot = self.read_byte();
self.stack.items[slot] = self.peek(0); self.stack[slot] = self.peek(0);
}, },
@intFromEnum(OpCode.OP_JUMP) => { @intFromEnum(OpCode.OP_JUMP) => {
const offset = self.read_short(); const offset = self.read_short();
@ -226,11 +226,14 @@ pub const VM = struct {
} }
pub fn push(self: *VM, value: Value) !void { pub fn push(self: *VM, value: Value) !void {
try self.stack.append(value); self.stack[self.stack_top] = value;
self.stack_top += 1;
} }
pub fn pop(self: *VM) Value { pub fn pop(self: *VM) Value {
return self.stack.pop(); const value = self.stack[self.stack_top - 1];
self.stack_top -= 1;
return value;
} }
pub fn binary_op(self: *VM, op: OpCode) !InterpretResult { pub fn binary_op(self: *VM, op: OpCode) !InterpretResult {
@ -276,7 +279,7 @@ pub const VM = struct {
} }
pub fn peek(self: *VM, distance: usize) Value { pub fn peek(self: *VM, distance: usize) Value {
return self.stack.items[self.stack.items.len - 1 - distance]; return self.stack[self.stack_top - 1 - distance];
} }
pub fn runtime_error(self: *VM, err_msg: []const u8) void { pub fn runtime_error(self: *VM, err_msg: []const u8) void {