=================== Fill screen red ===============================
    mov r14,0x8000
    mov r0,0xF2000000   ; video control registers
    mov r2,0
    st8 r0,r2           ; set 1 to in ctrl reg will switch to text mode
    mov r3,0xF0000000 ; base addresse for vga buffer
    mov r1,0
    mov r5,0xFF0000FF ; red with alpha to 100%
    mov r2,64000      ; 320*200 pixels
l:  st32 r3,r5
    add r3,4
    sub r2,1
    cmp r2,0
    jmp.nz l
    break

=================== Call a function ===============================
    mov   r14,0x8000
    push  0x12345678
    push  0xAAAAAAAA
    call  func
    pop   r0
    pop   r0
    break
func: mov r0,r14
    add  r0,4
    ld32 r10,r0
    add  r0,4
    ld32 r11,r0
    ret

=================== Exception handler for Divide by zero ===============================
    mov r14,0x8000
    mov r1,3
    reg r1,exhandler
    div r1,0
    nop
    break
exhandler: pop r13
    add r13,8       ; pop the return address and add 8
    push r13        ; so we will return to the following instruction
    eret            ; effectively ignoring the faulty instruction


=================== Read data ===============================
    mov r14,0x8000
    ld32 r0,d
    mov  r1,d
    add  r1,4
    ld32 r1,r1
    break
d:  $WORD32 0xDEADBEEF
    $WORD32 0x0DEFACED


=================== switch video mode to text ===============================
    mov r14,0x8000
    mov r0,0xF2000000   ; video control registers
    mov r1,0xF1000000
    mov r2,1            
    st8 r0,r2           ; set 1 to in ctrl reg will switch to text mode
    mov r3,2000

    mov r2,0x0
l:  st8 r1,r2
    add r1,1
    add r2,1
    sub r3,1
    cmp r3,0
    break.z
    jmp l

=================== keyboard IRQ handler and write to screen  ===============================
    mov   r14,0x8000    ; stack
    movsi r14,0x9000    ; stack for int handlers
    movsi r10,0xF1000000
    movsi r1,0xF3000001
    mov   r10,0xF2000000
    mov   r1,1
    st8   r10,r1         ; switch to text mode
    mov   r1,1
    ireg  r1,handler     ; register irq1 handler
    mov   r5,242
    sti
q:  cmp   r5,242
    jmp.z q
    ud
handler:add   r5,1
    ld8   r2,r1           ; get key from buffer
    cmp   r2,32
    st8.ae  r10,r2      ; only print chars higher than 32
    add.ae  r10,1
    iret.ae
    cmp    r2,8
    sub.z  r10,1         ; backspace, return 2 before
    mov.z  r2,32
    st8.z  r10,r2
    iret.z
    mov    r11,r10
    sub    r11,0xF1000000
    mod    r11,80
    add    r10,80
    sub    r10,r11
    iret