2024-01-07 22:33:27 -06:00
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global PROC_SWITCH
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PROC_SWITCH: dw 0
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2022-09-14 21:54:59 -05:00
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2023-02-10 01:06:42 -06:00
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global TIMERVAL
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2024-01-07 22:33:27 -06:00
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global TIMERVAL_FRAC
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2023-02-01 20:42:05 -06:00
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TIMERVAL: dd 0
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2024-01-07 22:33:27 -06:00
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TIMERVAL_FRAC: dd 0
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2022-09-14 21:54:59 -05:00
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global timerHandler
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timerHandler:
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push eax
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push ds
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mov ax, 0x10
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mov ds, ax
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2024-01-07 22:33:27 -06:00
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; Value from PITPgrm
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add dword [TIMERVAL_FRAC], 0xfffdb8d0
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adc dword [TIMERVAL], 0
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2022-09-14 21:54:59 -05:00
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mov al, 0x20
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out 0x20, al
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2024-01-07 22:33:27 -06:00
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; Check task switch
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movzx eax, word [PROC_SWITCH]
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test eax, eax
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jnz task_switch
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2022-09-14 21:54:59 -05:00
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pop ds
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pop eax
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iret
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2024-01-07 22:33:27 -06:00
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extern save_current_task_int
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task_switch:
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mov word [PROC_SWITCH], 0
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pop ds
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pop eax
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call save_current_task_int
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iret
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2022-09-14 21:54:59 -05:00
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global picInit
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picInit:
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mov al, 0x11 ; initialization sequence
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out 0x20, al ; send to 8259A-1
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jmp $+2
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jmp $+2
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out 0xA0, al ; and to 8259A-2
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jmp $+2
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jmp $+2
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mov al, 0x20 ; start of hardware ints (0x20)
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out 0x21, al
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jmp $+2
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jmp $+2
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mov al, 0x28 ; start of hardware ints 2 (0x28)
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out 0xA1, al
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jmp $+2
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jmp $+2
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mov al, 0x04 ; 8259-1 is master
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out 0x21, al
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jmp $+2
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jmp $+2
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mov al, 0x02 ; 8259-2 is slave
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out 0xA1, al
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jmp $+2
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jmp $+2
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mov al, 0x01 ; 8086 mode for both
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out 0x21, al
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jmp $+2
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jmp $+2
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out 0xA1, al
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jmp $+2
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jmp $+2
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mov al, 0xFF ; all interrupts off for now
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out 0x21, al
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jmp $+2
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jmp $+2
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out 0xA1, al
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ret
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