bios

boot/boot.asm

@@ -1,3 +1,4 @@
+bits 16
 org 0x7c00
 
 halt:

boot/util.asm

@@ -0,0 +1,34 @@
+%define cr      0x0a
+%define lf      0x0d
+%define endl    0x0
+
+; Reads a character
+; out:
+;   al = asci character
+;   ah = scan code
+read_char:
+    mov ah, 0
+    int 0x16
+    ret
+
+; Prints a character
+; in:
+;   al = asci character to print
+print_char:
+    mov ah, 0x0e
+    int 0x10
+    ret
+
+; Prints a null terminated string
+; in:
+;   si = null terminated string pointer
+print_line:
+    .loop:
+        cmp byte [si], 0
+        je .done
+        mov al, [si]
+        call print_char
+        inc si
+        jmp .loop
+    .done:
+    ret

makefile

@@ -1,8 +1,8 @@
-boot.bin: boot.asm
-	nasm -o boot.bin boot.asm
+boot/boot.bin: boot/boot.asm
+	nasm -o boot/boot.bin boot/boot.asm
 
-run: boot.bin
-	qemu-system-x86_64 boot.bin
+run: boot/boot.bin
+	qemu-system-x86_64 -drive file=boot/boot.bin,format=raw,index=0,media=disk
 
 clean:
-	rm boot.bin
+	rm boot/boot.bin