279 lines
5.2 KiB
NASM
Executable file
279 lines
5.2 KiB
NASM
Executable file
; This is the exception de-multiplexer code.
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; All low-level exception handling routines do the following:
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; 1. disable interrupts
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; 2. push error code on the stack (if the exception did not already
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; do so! (Some exceptions automatically push the error code onto the
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; stack.)
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; 3. push the number of the exception onto the stack.
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; 4. call the common interrupt service routine function, which then
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; branches back out based on the exception number on the stack.
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; (We do this because we don't want to replicate again and again the code
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; to save the processor state.)
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;
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; Here come the interrupt service routines for the 32 exceptions.
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global _isr0
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global _isr1
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global _isr2
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global _isr3
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global _isr4
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global _isr5
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global _isr6
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global _isr7
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global _isr8
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global _isr9
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global _isr10
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global _isr11
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global _isr12
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global _isr13
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global _isr14
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global _isr15
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global _isr16
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global _isr17
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global _isr18
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global _isr19
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global _isr20
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global _isr21
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global _isr22
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global _isr23
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global _isr24
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global _isr25
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global _isr26
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global _isr27
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global _isr28
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global _isr29
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global _isr30
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global _isr31
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extern _promptA
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extern _promptB
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extern _promptC
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; 0: Divide By Zero Exception
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_isr0:
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push byte 0
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push byte 0
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jmp isr_common_stub
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; 1: Debug Exception
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_isr1:
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push byte 0
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push byte 1
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jmp isr_common_stub
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; 2: Non Maskable Interrupt Exception
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_isr2:
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push byte 0
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push byte 2
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jmp isr_common_stub
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; 3: Int 3 Exception
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_isr3:
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push byte 0
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push byte 3
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jmp isr_common_stub
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; 4: INTO Exception
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_isr4:
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push byte 0
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push byte 4
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jmp isr_common_stub
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; 5: Out of Bounds Exception
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_isr5:
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push byte 0
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push byte 5
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jmp isr_common_stub
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; 6: Invalid Opcode Exception
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_isr6:
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push byte 0
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push byte 6
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jmp isr_common_stub
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; 7: Coprocessor Not Available Exception
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_isr7:
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push byte 0
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push byte 7
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jmp isr_common_stub
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; 8: Double Fault Exception (With Error Code!)
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_isr8:
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push byte 8
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jmp isr_common_stub
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; 9: Coprocessor Segment Overrun Exception
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_isr9:
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push byte 0
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push byte 9
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jmp isr_common_stub
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; 10: Bad TSS Exception (With Error Code!)
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_isr10:
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push byte 10
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jmp isr_common_stub
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; 11: Segment Not Present Exception (With Error Code!)
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_isr11:
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push byte 11
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jmp isr_common_stub
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; 12: Stack Fault Exception (With Error Code!)
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_isr12:
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push byte 12
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jmp isr_common_stub
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; 13: General Protection Fault Exception (With Error Code!)
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_isr13:
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push byte 13
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jmp isr_common_stub
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; 14: Page Fault Exception (With Error Code!)
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_isr14:
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push byte 14
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jmp isr_common_stub
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; 15: Reserved Exception
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_isr15:
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push byte 0
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push byte 15
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jmp isr_common_stub
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; 16: Floating Point Exception
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_isr16:
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push byte 0
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push byte 16
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jmp isr_common_stub
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; 17: Alignment Check Exception
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_isr17:
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push byte 0
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push byte 17
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jmp isr_common_stub
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; 18: Machine Check Exception
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_isr18:
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push byte 0
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push byte 18
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jmp isr_common_stub
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; 19: Reserved
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_isr19:
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push byte 0
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push byte 19
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jmp isr_common_stub
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; 20: Reserved
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_isr20:
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push byte 0
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push byte 20
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jmp isr_common_stub
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; 21: Reserved
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_isr21:
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push byte 0
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push byte 21
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jmp isr_common_stub
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; 22: Reserved
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_isr22:
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push byte 0
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push byte 22
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jmp isr_common_stub
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; 23: Reserved
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_isr23:
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push byte 0
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push byte 23
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jmp isr_common_stub
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; 24: Reserved
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_isr24:
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push byte 0
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push byte 24
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jmp isr_common_stub
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; 25: Reserved
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_isr25:
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push byte 0
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push byte 25
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jmp isr_common_stub
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; 26: Reserved
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_isr26:
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push byte 0
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push byte 26
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jmp isr_common_stub
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; 27: Reserved
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_isr27:
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push byte 0
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push byte 27
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jmp isr_common_stub
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; 28: Reserved
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_isr28:
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push byte 0
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push byte 28
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jmp isr_common_stub
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; 29: Reserved
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_isr29:
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push byte 0
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push byte 29
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jmp isr_common_stub
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; 30: Reserved
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_isr30:
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push byte 0
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push byte 30
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jmp isr_common_stub
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; 31: Reserved
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_isr31:
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push byte 0
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push byte 31
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jmp isr_common_stub
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; The common stub below will pun out into C. Let the
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; assembler know that the function is defined in 'exceptions.C'.
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extern _lowlevel_dispatch_exception
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; This is the common low-level stub for the exception handler.
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; It saves the processor state, sets up for kernel mode
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; segments, calls the C-level exception handler,
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; and finally restores the stack frame.
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isr_common_stub:
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pusha
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push ds
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push es
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push fs
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push gs
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mov eax, esp ; Push us the stack
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push eax
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mov eax, _lowlevel_dispatch_exception
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call eax ; A special call, preserves the 'eip' register
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pop eax
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pop gs
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pop fs
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pop es
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pop ds
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popa
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add esp, 8 ; Ceans up the pushed error code and pushed ISR number
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iret ; pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP1
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; load the IDT defined in '_idtp' into the processor.
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; This is declared in C as 'extern void _idt_load();'
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; In turn, the variable '_idtp' is defined in file 'idt.C'.
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global _idt_load
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extern _idtp
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_idt_load:
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lidt [_idtp]
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ret
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