Add a few toys

2025-09-24 00:40:56 +02:00
parent 9daf8d7f97
commit ee97876115
8 changed files with 250 additions and 0 deletions
--- a/debug.asm
+++ b/debug.asm
@@ -0,0 +1,66 @@
+BITS 16
+CPU 8086
+
+org 0x7000
+
+_start:
+    jmp main
+
+hexdigits:
+    db "0123456789abcdef"
+
+putc:
+    push bx
+    push bp
+    mov ah, 0x0e
+    xor bh, bh
+    int 0x10
+    pop bp
+    pop bx
+    ret
+
+printnibble:
+    push si
+    push bx
+    mov si, hexdigits
+    xor bh, bh
+    mov bl, al
+    and bl, 0xf
+    mov al, cs:[si+bx]
+    call putc
+    pop bx
+    pop si
+    ret
+
+printi8:
+    push bx
+    mov bl, al
+    mov cl, 4
+    shr al, cl 
+    call printnibble
+    mov al, bl
+    call printnibble
+    pop bx
+    ret
+
+printi16:
+    push bx
+    mov bx, ax
+    mov al, ah
+    call printi8
+    mov al, bl
+    call printi8
+    pop bx
+    ret
+    
+main:
+    mov bp, sp
+    mov si, [bp+4]
+    mov si, [si]
+    mov ax, [si]
+    call printi16
+    mov al, 0x0d
+    call putc
+    mov al, 0x0a
+    call putc
+    retf 2