102 lines
1.9 KiB
NASM
102 lines
1.9 KiB
NASM
; Data table for interrupts
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; cs:word for service routine
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intr_table:
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dw iret ; 0 Divide by Zero
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dw iret ; 1 Single Step
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dw iret ; 2 Parity error routine (NMI)
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dw debug_reg_ir ; 3 Break
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dw iret ; 4 Overflow
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dw iret ; 5 Print Screen
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dw iret ; 6 Mouse button control
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dw iret ; 7 Reserved
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dw irq0 ; 8 System Clock interrupt
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dw irq1 ; 9 Keyboard interrupt
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dw irq2 ; 10 RTC interrupt
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dw irq3 ; 11 COMMS
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dw irq4 ; 12 COMMS
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dw irq5 ; 13 Hard Disk
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dw irq6 ; 14 Floppy Disk interrupt routine
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dw irq7 ; 15 Printer interrupt
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; LSB is IRQ0, MSB is IRQ16
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; A IRQ will set their bit to 1, so userspace may poll it via wait_irq
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intr_flip:
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dw 0
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intr_init:
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push ds
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push es
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; backup intr 0x0n to 0x4n
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xor ax, ax
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mov ds, ax ; read from IVT
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mov es, ax ; write to IVT
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mov si, ax ; read from start of IVT table
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mov di, 0x0100 ; write to offset of int 0x40 address
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mov cx, 0x0020 ; 0x10 vectors, segment:offset each
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repe movsw
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; now setup our own handlers
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mov ax, cs
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mov ds, ax ; read from local segment
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mov si, intr_table ; read from intr_table
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mov di, 0x0000 ; write to start of IVT table
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mov cx, 0x0010 ; 0x10 vectors, one offset each
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.loop:
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movsw ; read offset, write offset
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mov ax,cs
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stosw ; write segment
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loop .loop
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pop es
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pop ds
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ret
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irq0:
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int 0x48
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or byte [intr_flip], 0x01
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jmp irqret
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irq1:
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int 0x49
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or byte [intr_flip], 0x02
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push ax
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mov ax, [intr_flip]
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call kprint8
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mov word [intr_flip], 0x0000
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pop ax
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jmp irqret
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irq2:
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int 0x4A
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or byte [intr_flip], 0x04
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jmp irqret
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irq3:
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int 0x4B
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or byte [intr_flip], 0x08
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jmp irqret
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irq4:
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int 0x4C
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or byte [intr_flip], 0x10
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jmp irqret
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irq5:
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int 0x4D
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or byte [intr_flip], 0x20
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jmp irqret
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irq6:
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int 0x4E
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or byte [intr_flip], 0x40
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jmp irqret
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irq7:
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int 0x4F
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or byte [intr_flip], 0x80
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jmp irqret
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hwiret:
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mov al,20h
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out 20h,al
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irqret:
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iret:
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iret |