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61 lines
1.6 KiB
NASM
61 lines
1.6 KiB
NASM
[org 0x7000]
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start:
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mov [bootdev], dl
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mov ah, 06h ; Scroll up function
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xor al, al ; Clear entire screen
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xor cx, cx ; Upper left corner CH=row, CL=column
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mov dx, 184FH ; lower right corner DH=row, DL=column
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mov bh, 4Fh ; YellowOnBlue
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int 10H ; execute interrupt
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mov al, 182 ; meaning that we're about to load
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out 43h, al ; prepare speaker for output
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mov ax, 2153 ; frequency countdown value is stored in ax. It is calculated by
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out 42h, al ; Output low byte.
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mov al, ah ; Output high byte.
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out 42h, al
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in al, 61h
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or al, 00000011b
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out 61h, al ; Send the new value
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; mov bx, 200 ; Pause for duration of note.
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mov al, 0
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mov ah, 86h
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mov cx, 1
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mov dx, 200
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int 15h
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;.pause1:
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; mov cx, 65535
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;.pause2:
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; dec cx
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; jne .pause2
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; dec bx
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; jne .pause1
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in al, 61h ; Turn off note (get value from
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; port 61h).
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and al, 11111100b ; Reset bits 1 and 0.
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out 61h, al ; Send new value.
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waitforkey:
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mov ah, 0x00
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int 0x16
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cmp ah, 01h
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je exit
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jmp waitforkey
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exit:
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in al, 61h ; Turn off note (get value from
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; port 61h).
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and al, 11111100b ; Reset bits 1 and 0.
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out 61h, al ; Send new value.
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mov dl, [bootdev]
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jmp 0x0:0x1000
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bootdev db 0x80 ; Boot device number
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