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Zig Bare Bones: Difference between revisions
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{{Stub}}
{{TutorialExplain}}
{{Sole Editor}}
In this tutorial, we'll make a simple hello world kernel in Zig.
== Prerequisites ==
First off, you'll need:
* The [[Zig]] compiler, at least version 0.
* [[GRUB]] as our bootloader to boot the kernel
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=== build.zig ===
<
const std = @import("std");
const Builder = @import("std").build.Builder;
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};
const
const kernel = b.addExecutable(
.name = "kernel.
.root_source_file = b.path("src/main.zig"),
.target = target,
kernel.setLinkerScriptPath(.{ .path = "src/linker.ld" });▼
.code_model = .kernel,
});
b.installArtifact(kernel);
const kernel_step = b.step("kernel", "Build the kernel");
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run_step.dependOn(&run_cmd.step);
}
</syntaxhighlight>
=== src/main.zig ===
<
const console = @import("console.zig");
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console.puts("Hello world!");
}
</syntaxhighlight>
=== src/console.zig ===
<
const fmt = @import("std").fmt;
const
const VGA_WIDTH = 80;
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LightMagenta = 13,
LightBrown = 14,
White = 15,
};
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var column: usize = 0;
var color = vgaEntryColor(ConsoleColors.LightGray, ConsoleColors.Black);
var buffer = @
fn vgaEntryColor(fg: ConsoleColors, bg: ConsoleColors) u8 {
return @enumToInt(fg) | (@enumToInt(bg) << 4);
}
fn vgaEntry(uc: u8, new_color: u8) u16 {
var c: u16 = new_color;
return uc | (c << 8);
}
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pub fn clear() void {
}
pub fn putCharAt(c: u8, new_color: u8, x: usize, y: usize) void {
const index
buffer[index] = vgaEntry(c, new_color);
}
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pub fn putChar(c: u8) void {
putCharAt(c, color, column, row);
column += 1;
if (column == VGA_WIDTH) {
column = 0;
row += 1;
if (row == VGA_HEIGHT)
row = 0;
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pub fn puts(data: []const u8) void {
for (data) |
putChar(
}
pub const writer = Writer(void, error{}, callback){ .context = {} };
fn callback(_: void, string: []const u8) error{}!usize {
puts(string);
return string.len;
}
pub fn printf(comptime format: []const u8, args: anytype) void {
▲ puts(fmt.bufPrint(&buf, format, args) catch unreachable);
}
</syntaxhighlight>
=== src/linker.ld ===
A [[linker script]] is also needed. This file tells the linker to place our code at the base address of 1M. In general user-space programming, code are placed at much higher areas, but that requires [[virtual memory]] to be available, or else only few computers could provide such a large physical memory space.
We also asks the linker to place <code>.multiboot</code> section at first, because the Multiboot specification says that the Multiboot header must be at the first 8KiB of the kernel file.
<pre>
ENTRY(_start)
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. = 1M;
KEEP(*(.multiboot))
}
.text : ALIGN(4K) {
▲ *(.multiboot)
*(.text)
}
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}
}
</
=== src/grub.cfg ===
Finally, the last thing you need is a GRUB configuration, which tells the GRUB bootloader how to boot our kernel.
<code>menuentry</code> adds a menu entry to the screen. When you press ENTER in the GRUB menu, GRUB will run the commands in the menu block.
<code>multiboot</code> asks GRUB to load our kernel from <code>/boot/kernel.elf</code>, and GRUB automatically runs <code>boot</code> after the menu block, which will fire the boot.
<syntaxhighlight lang="unixconfig">
menuentry "Zig Bare Bones" {
multiboot /boot/kernel.elf
}
</syntaxhighlight>
== Build ==
Now that our kernel code is done, we'll now build our kernel by running the command below:
<
$ zig build
</syntaxhighlight>
To boot our kernel, simply run this command:
<
$ zig build run
</syntaxhighlight>
[[Category: Bare bones tutorials]] [[Category:Zig]]
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