actually maybe let's not just yet

build.zig

@@ -10,11 +10,11 @@ pub fn build(b: *std.Build) void {
         .outputname = "bootloader.bin",
         .flags = &.{"-f bin"},
     });
-    //const kernel = addNasmFiles(b, AddNasmFilesOptions{
+    const kernel = addNasmFiles(b, AddNasmFilesOptions{
-    //    .filename = "src/kernel.asm",
+        .filename = "src/kernel.asm",
-    //    .outputname = "kernel.bin",
+        .outputname = "kernel.bin",
-    //    .flags = &.{"-f bin"},
+        .flags = &.{"-f bin"},
-    //});
+    });
 
     const target = b.standardTargetOptions(.{
         .default_target = .{
@@ -23,22 +23,10 @@ pub fn build(b: *std.Build) void {
         },
     });
 
-    const kernel_mod = b.addModule("kernel", .{
-        .root_source_file = b.path("src/kernel.zig"),
-        .target = target,
-    });
-
-    const kernel = b.addExecutable(.{
-        .root_module = kernel_mod,
-        .linkage = .static,
-        .name = "kernel",
-    });
-
     const floppy = createFloppy(b, "main_floppy.img");
-    formatFloppyFat12(b, floppy);
 
     var installToFloppy = installImgToFloppy(b, floppy, bootloader, &.{
-        NamedFile{ .file = kernel.getEmittedBin(), .name = "::kernel.bin" },
+        NamedFile{ .file = kernel, .name = "::kernel.bin" },
         NamedFile{ .file = b.path("src/reference_implementations/test.txt"), .name = "::test.txt" },
     });
 
@@ -91,16 +79,16 @@ fn createFloppy(b: *std.Build, name: []const u8) LazyPath {
     return Floppy;
 }
 
-fn formatFloppyFat12(b: *std.Build, floppy: LazyPath) void {
+fn installImgToFloppy(b: *std.Build, floppy: LazyPath, bootloader: LazyPath, additional_files: []const NamedFile) *std.Build.Step.Run {
     const mkfs = b.addSystemCommand(&.{ "mkfs.fat", "-F12", "-nNBOS" });
     mkfs.addFileArg(floppy);
-}
+    mkfs.has_side_effects = true;
 
-fn installImgToFloppy(b: *std.Build, floppy: LazyPath, bootloader: LazyPath, additional_files: []const NamedFile) *std.Build.Step.Run {
     const dd = b.addSystemCommand(&.{"dd"});
     dd.addPrefixedFileArg("if=", bootloader);
     dd.addPrefixedFileArg("of=", floppy);
     dd.addArg("conv=notrunc");
+    dd.step.dependOn(&mkfs.step);
 
     var last_step = dd;
     for (additional_files) |f| {

src/bootloader.asm

@@ -37,7 +37,6 @@ ebr_system_id:				db 'FAT12   '           ; 8 bytes
 
 
 
-
 start:
 	; setup data segments
 	mov ax, 0		; use ax as and intermediary as we can't write to es/ds directly
@@ -364,7 +363,6 @@ disk_reset:
 	popa
 	ret
 
-
 msg_loading: 								db 'starting zos', ENDL, 0
 msg_read_failed:							db 'error on floppy read', ENDL, 0
 msg_kernel_not_found:						db 'kernel.bin not found', ENDL, 0

src/kernel.asm

@@ -2,26 +2,38 @@
 org 0x0
 bits 16
 
+
+%define ENDL 0x0D, 0x0A
+
+
+start:
+	mov si, msg_init
+	call echo
+
+.halt:
+	cli
+	hlt
+
+; 
 ; echo:
 ; print something to the screen
 ;  - ds:si points to string
 ;
-global _echo:function
+echo:
-_echo:
 	; save the registers we want to modify
 	push si
 	push ax
 	push bx
 
-	mov ah, 0xe
-	mov bh, 0
-
 .loop:
 	lodsb			; load byte from ds:si to al
 	or al, al		; check if next char is null
 	jz .done
 
+	mov ah, 0x0E
+	mov bh, 0
 	int 0x10
+
 	jmp .loop
 
 .done:
@@ -29,3 +41,5 @@ _echo:
 	pop ax
 	pop si
 	ret
+
+msg_init: 								db 'started kernel', ENDL, 0

src/kernel.zig

@@ -1,25 +0,0 @@
-fn BIOSprint(string: []const u8) void {
-    asm volatile (
-        \\pushw %%ax
-        \\pushw %%bx
-    );
-    for (string) |char| {
-        asm volatile (
-            \\movb $0x0E, %%ah
-            \\movb $0, %%bh
-            \\int $0x10
-            :
-            : [arg1] "{al}" (char),
-        );
-    }
-    asm volatile (
-        \\popw %%bx
-        \\popw %%ax
-    );
-}
-
-const std = @import("std");
-
-pub fn main() void {
-    BIOSprint("kernel loaded");
-}