72 lines
1.6 KiB
Zig
72 lines
1.6 KiB
Zig
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const std = @import("std");
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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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pub Return: u8 = 0,
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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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offset: usize,
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) !usize {
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try stdout.print("{}\n", name);
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return offset + 1;
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}
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pub const Chunk = struct {
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count: usize,
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code: []u8,
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allocator: *Allocator,
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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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};
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}
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pub fn write(self: *Chunk, byte: u8) !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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}
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self.code[self.count] = byte;
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self.count += 1;
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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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var instruction = self.code[index];
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if (instruction == 0) {
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return try simpleInstruction(stdout, "OP_RETURN", 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) : (i += 1) {
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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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