287 lines
8.7 KiB
Zig
287 lines
8.7 KiB
Zig
const std = @import("std");
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const value = @import("value.zig");
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const Allocator = std.mem.Allocator;
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// hack. ugly hack. zig has compiler crash.
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const AllOpcodes = struct {
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Return: u8 = 0,
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Constant: u8 = 1,
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ConstantLong: u8 = 2,
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Add: u8 = 3,
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Subtract: u8 = 4,
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Multiply: u8 = 5,
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Divide: u8 = 6,
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Negate: u8 = 7,
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// basic type op codes
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Nil: u8 = 8,
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True: u8 = 9,
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False: u8 = 10,
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Not: u8 = 11,
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// comparison op codes!
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Equal: u8 = 12,
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Greater: u8 = 13,
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Less: u8 = 14,
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Print: u8 = 15,
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Pop: u8 = 16,
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DefineGlobal: u8 = 17,
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DefineGlobalLong: u8 = 18,
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GetGlobal: u8 = 19,
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GetGlobalLong: u8 = 20,
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SetGlobal: u8 = 21,
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SetGlobalLong: u8 = 22,
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GetLocal: u8 = 23,
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SetLocal: u8 = 24,
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};
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pub const OpCode = AllOpcodes{};
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fn simpleInstruction(
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stdout: var,
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comptime name: []const u8,
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index: usize,
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) !usize {
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try stdout.print("{}\n", name);
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return index + 1;
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}
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fn constantInstruction(
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stdout: var,
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comptime name: []const u8,
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chunk: *Chunk,
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index: usize,
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) !usize {
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// get the constant's index in constants slice
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var idx = chunk.code[index + 1];
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try stdout.print("\t{}\t{} '", name, idx);
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try value.printValue(stdout, chunk.constants.values[idx]);
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try stdout.print("'\n");
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return index + 2;
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}
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fn constantLongInstruction(
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stdout: var,
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comptime name: []const u8,
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chunk: *Chunk,
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offset: usize,
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) !usize {
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// constantLong uses three u8's that encode a u24 as the
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// contants' index.
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var v3: u8 = chunk.code[offset + 1];
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var v2: u8 = chunk.code[offset + 2];
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var v1: u8 = chunk.code[offset + 3];
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var idx: u24 = (@intCast(u24, v3) << 16) | (@intCast(u24, v2) << 8) | v1;
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try stdout.print("\t{}\t{} '", name, idx);
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try value.printValue(stdout, chunk.constants.values[idx]);
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try stdout.print("'\n");
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return offset + 4;
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}
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fn byteInstruction(
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stdout: var,
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name: []const u8,
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chunk: *Chunk,
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index: usize,
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) !usize {
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var slot: u8 = chunk.code[index + 1];
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try stdout.print("{} {}", name, slot);
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return index + 2;
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}
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pub const ConstantIndexTag = enum {
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Small,
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Long,
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};
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pub const ConstantIndex = union(ConstantIndexTag) {
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Small: u8,
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Long: [3]u8,
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};
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pub const Chunk = struct {
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count: usize,
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lines: []usize,
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code: []u8,
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allocator: *Allocator,
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constants: value.ValueList,
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pub fn init(allocator: *Allocator) !Chunk {
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return Chunk{
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.count = 0,
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.allocator = allocator,
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.code = try allocator.alloc(u8, 0),
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.lines = try allocator.alloc(usize, 0),
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.constants = try value.ValueList.init(allocator),
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};
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}
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pub fn write(self: *Chunk, byte: u8, line: usize) !void {
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if (self.code.len < self.count + 1) {
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self.code = try self.allocator.realloc(
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self.code,
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self.count + 1,
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);
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self.lines = try self.allocator.realloc(
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self.lines,
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self.count + 1,
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);
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}
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self.code[self.count] = byte;
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self.lines[self.count] = line;
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self.count += 1;
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}
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pub fn addConstant(self: *Chunk, val: value.Value) !u8 {
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try self.constants.write(val);
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return self.constants.count - 1;
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}
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pub fn writeConstantRaw(
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self: *Chunk,
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val: value.Value,
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line: usize,
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) !ConstantIndex {
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try self.constants.write(val);
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var constant_idx = self.constants.count - 1;
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if (constant_idx < 256) {
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var idx_small = @intCast(u8, constant_idx);
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return ConstantIndex{ .Small = idx_small };
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} else {
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var idx_u24: u24 = @intCast(u24, constant_idx);
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const mask = @intCast(u24, 0xff);
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const v1: u8 = @intCast(u8, idx_u24 & mask);
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const v2: u8 = @intCast(u8, (idx_u24 >> 8) & mask);
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const v3: u8 = @intCast(u8, (idx_u24 >> 16) & mask);
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return ConstantIndex{ .Long = [_]u8{ v3, v2, v1 } };
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}
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}
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pub fn writeConstant(
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self: *Chunk,
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val: value.Value,
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line: usize,
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) !ConstantIndex {
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var idx = try self.writeConstantRaw(val, line);
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switch (idx) {
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.Small => |idx_small| blk: {
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try self.write(OpCode.Constant, line);
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try self.write(idx_small, line);
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break :blk;
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},
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.Long => |long_u8| blk: {
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try self.write(OpCode.ConstantLong, line);
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try self.write(long_u8[0], line);
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try self.write(long_u8[1], line);
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try self.write(long_u8[2], line);
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},
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else => unreachable,
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}
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return idx;
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}
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pub fn disassembleInstruction(
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self: *Chunk,
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stdout: var,
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index: usize,
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) !usize {
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try stdout.print("{} ", index);
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if (index > 0 and self.lines[index] == self.lines[index - 1]) {
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try stdout.print(" | ");
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} else {
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try stdout.print("{} ", self.lines[index]);
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}
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var instruction = self.code[index];
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if (instruction == OpCode.Return) {
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return try simpleInstruction(stdout, "OP_RETURN", index);
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} else if (instruction == OpCode.Constant) {
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return try constantInstruction(stdout, "OP_CONSTANT", self, index);
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} else if (instruction == OpCode.ConstantLong) {
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return try constantLongInstruction(
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stdout,
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"OP_CONSTANT_LONG",
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self,
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index,
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);
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} else if (instruction == OpCode.Negate) {
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return try simpleInstruction(stdout, "OP_NEGATE", index);
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} else if (instruction == OpCode.Add) {
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return try simpleInstruction(stdout, "OP_ADD", index);
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} else if (instruction == OpCode.Subtract) {
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return try simpleInstruction(stdout, "OP_SUBTRACT", index);
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} else if (instruction == OpCode.Multiply) {
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return try simpleInstruction(stdout, "OP_MULTIPLY", index);
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} else if (instruction == OpCode.Divide) {
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return try simpleInstruction(stdout, "OP_DIVIDE", index);
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} else if (instruction == OpCode.Nil) {
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return try simpleInstruction(stdout, "OP_NIL", index);
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} else if (instruction == OpCode.True) {
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return try simpleInstruction(stdout, "OP_TRUE", index);
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} else if (instruction == OpCode.False) {
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return try simpleInstruction(stdout, "OP_FALSE", index);
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} else if (instruction == OpCode.Not) {
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return try simpleInstruction(stdout, "OP_NOT", index);
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} else if (instruction == OpCode.Equal) {
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return try simpleInstruction(stdout, "OP_EQUAL", index);
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} else if (instruction == OpCode.Greater) {
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return try simpleInstruction(stdout, "OP_GREATER", index);
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} else if (instruction == OpCode.Less) {
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return try simpleInstruction(stdout, "OP_LESS", index);
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} else if (instruction == OpCode.Print) {
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return try simpleInstruction(stdout, "OP_PRINT", index);
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} else if (instruction == OpCode.Pop) {
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return try simpleInstruction(stdout, "OP_POP", index);
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} else if (instruction == OpCode.DefineGlobal) {
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return try constantInstruction(stdout, "OP_DEFGLOBAL", self, index);
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} else if (instruction == OpCode.DefineGlobalLong) {
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return try constantLongInstruction(stdout, "OP_DEFGLOBAL_LONG", self, index);
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} else if (instruction == OpCode.GetGlobal) {
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return try constantInstruction(stdout, "OP_GETGLOBAL", self, index);
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} else if (instruction == OpCode.GetGlobalLong) {
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return try constantLongInstruction(stdout, "OP_GETGLOBAL_LONG", self, index);
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} else if (instruction == OpCode.SetGlobal) {
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return try constantInstruction(stdout, "OP_SETGLOBAL", self, index);
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} else if (instruction == OpCode.SetGlobalLong) {
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return try constantLongInstruction(stdout, "OP_SETGLOBAL_LONG", self, index);
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} else if (instruction == OpCode.GetLocal) {
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return try byteInstruction(stdout, "OP_GETLOCAL", self, index);
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} else if (instruction == OpCode.SetLocal) {
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return try byteInstruction(stdout, "OP_GETLOCAL", self, index);
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} else {
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try stdout.print("Unknown opcode: {}\n", instruction);
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return index + 1;
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}
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}
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pub fn disassemble(self: *Chunk, stdout: var, name: []const u8) !void {
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try stdout.print("== {} ==\n", name);
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var i: usize = 0;
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while (i < self.count) {
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i = try self.disassembleInstruction(stdout, i);
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}
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}
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};
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