%define IRQ0 32 %define IRQ1 33 %define IRQ2 34 %define IRQ3 35 %define IRQ4 36 %define IRQ5 37 %define IRQ6 38 %define IRQ7 39 %define IRQ8 40 %define IRQ9 41 %define IRQ10 42 %define IRQ11 43 %define IRQ12 44 %define IRQ13 45 %define IRQ14 46 %define IRQ15 47 %macro ISR_NOERRCODE 1 ; define a macro, taking one parameter ;[GLOBAL isr%1] ; %1 accesses the first parameter. isr%1: cli push byte 0 push byte %1 jmp isr_common_stub %endmacro %macro ISR_ERRCODE 1 ;[GLOBAL isr%1] isr%1: cli push byte %1 jmp isr_common_stub %endmacro ;idt_set_gate %macro SETUP_ISR_X 2 mov eax,%1 ;base isr mov [idt_temp], word ax ;lower 16 bits mov [idt_temp+2],word 0x08 ;kernel segment selector mov [idt_temp+4],byte 0x0 ;always 0 ; We must change 0x8E with 0xEE below when we get to using user-mode. ; It sets the interrupt gate's privilege level to 3. mov [idt_temp+5],byte 0x8E ;0x8E | 0x60 = 0xEE... we have to enable this later on shld edx,eax,16 mov [idt_temp+6],word dx ;store idt_temp in idt and repeat the process mov esi,idt_temp mov edi,idt+(%2*8) mov ecx,2 rep movsd ;verify this is working!!!!!!!!!! DO NOT LET IT AS IS WITHOUT CHECKING %endmacro ; This macro creates a stub for an IRQ - the first parameter is ; the IRQ number, the second is the ISR number it is remapped to. %macro IRQ 2 global irq%1 irq%1: cli push byte 0 push byte %2 jmp irq_common_stub %endmacro SECTION .data isr_notification: db 'Recieved Interrupt.',`\n`,0x0 ;;this is our IDT entry idt_ptr_struct: dw idt_end - idt - 1 ; size of the GDT dd idt ; linear address of GDT ;256 idt entries. each entry has 8 bytes. 256*8 =2048 SECTION .text extern prints global init_idt ;first we have to create the interrupt handlers ISR_NOERRCODE 0 ISR_NOERRCODE 1 ISR_NOERRCODE 2 ISR_NOERRCODE 3 ISR_NOERRCODE 4 ISR_NOERRCODE 5 ISR_NOERRCODE 6 ISR_NOERRCODE 7 ISR_ERRCODE 8 ISR_NOERRCODE 9 ISR_ERRCODE 10 ISR_ERRCODE 11 ISR_ERRCODE 12 ISR_ERRCODE 13 ISR_ERRCODE 14 ISR_NOERRCODE 15 ISR_NOERRCODE 16 ISR_NOERRCODE 17 ISR_NOERRCODE 18 ISR_NOERRCODE 19 ISR_NOERRCODE 20 ISR_NOERRCODE 21 ISR_NOERRCODE 22 ISR_NOERRCODE 23 ISR_NOERRCODE 24 ISR_NOERRCODE 25 ISR_NOERRCODE 26 ISR_NOERRCODE 27 ISR_NOERRCODE 28 ISR_NOERRCODE 29 ISR_NOERRCODE 30 ISR_NOERRCODE 31 IRQ 0, 32 IRQ 1, 33 IRQ 2, 34 IRQ 3, 35 IRQ 4, 36 IRQ 5, 37 IRQ 6, 38 IRQ 7, 39 IRQ 8, 40 IRQ 9, 41 IRQ 10, 42 IRQ 11, 43 IRQ 12, 44 IRQ 13, 45 IRQ 14, 46 IRQ 15, 47 init_idt: ;fill it with zero mov al,0x0 mov ecx,2048 mov edi,idt rep stosb ;;BREAKPOINT: verify it's doing this as it should ;xch bx,bx ;Remap the irq table. ;outb port, byte mov al, 0x11 out 0x20, al out 0xA0, al mov al,0x20 out 0x21, al mov al,0x28 out 0xA1, al mov al,0x04 out 0x21, al mov al,0x02 out 0xA1, al mov al,0x01 out 0x21, al out 0xA1, al xor al,al out 0x21, al out 0xA1, al ;set idt table: SETUP_ISR_X isr0,0 SETUP_ISR_X isr1,1 SETUP_ISR_X isr2,2 SETUP_ISR_X isr3,3 SETUP_ISR_X isr4,4 SETUP_ISR_X isr5,5 SETUP_ISR_X isr6,6 SETUP_ISR_X isr7,7 SETUP_ISR_X isr8,8 SETUP_ISR_X isr9,9 SETUP_ISR_X isr10,10 SETUP_ISR_X isr11,11 SETUP_ISR_X isr12,12 SETUP_ISR_X isr13,13 SETUP_ISR_X isr14,14 SETUP_ISR_X isr15,15 SETUP_ISR_X isr16,16 SETUP_ISR_X isr17,17 SETUP_ISR_X isr18,18 SETUP_ISR_X isr19,19 SETUP_ISR_X isr20,20 SETUP_ISR_X isr21,21 SETUP_ISR_X isr22,22 SETUP_ISR_X isr23,23 SETUP_ISR_X isr24,24 SETUP_ISR_X isr25,25 SETUP_ISR_X isr26,26 SETUP_ISR_X isr27,27 SETUP_ISR_X isr28,28 SETUP_ISR_X isr29,29 SETUP_ISR_X isr30,30 SETUP_ISR_X isr31,31 SETUP_ISR_X irq0,32 SETUP_ISR_X irq1,33 SETUP_ISR_X irq2,34 SETUP_ISR_X irq3,35 SETUP_ISR_X irq4,36 SETUP_ISR_X irq5,37 SETUP_ISR_X irq6,38 SETUP_ISR_X irq7,39 SETUP_ISR_X irq8,40 SETUP_ISR_X irq9,41 SETUP_ISR_X irq10,42 SETUP_ISR_X irq11,43 SETUP_ISR_X irq12,44 SETUP_ISR_X irq13,45 SETUP_ISR_X irq14,46 SETUP_ISR_X irq15,47 ;load new idt lidt [idt_ptr_struct] ret ;s is our common ISR stub. It saves the processor state, sets ; up for kernel mode segments, calls the C-level fault handler, ; and finally restores the stack frame. isr_common_stub: pusha ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax mov ax, ds ; Lower 16-bits of eax = ds. push eax ; save the data segment descriptor mov ax, 0x10 ; load the kernel data segment descriptor mov ds, ax mov es, ax mov fs, ax mov gs, ax call isr_handler pop eax ; reload the original data segment descriptor mov ds, ax mov es, ax mov fs, ax mov gs, ax popa ; Pops edi,esi,ebp... add esp, 8 ; Cleans up the pushed error code and pushed ISR number sti iret ; pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP isr_handler: mov esi,isr_notification call prints ret ; This is our common IRQ stub. It saves the processor state, sets ; up for kernel mode segments, calls the C-level fault handler, ; and finally restores the stack frame. irq_common_stub: pusha ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax mov ax, ds ; Lower 16-bits of eax = ds. push eax ; save the data segment descriptor mov ax, 0x10 ; load the kernel data segment descriptor mov ds, ax mov es, ax mov fs, ax mov gs, ax call irq_handler pop ebx ; reload the original data segment descriptor mov ds, bx mov es, bx mov fs, bx mov gs, bx popa ; Pops edi,esi,ebp... add esp, 8 ; Cleans up the pushed error code and pushed ISR number sti iret ; pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP irq_handler: mov esi,isr_notification call prints ret SECTION .bss idt: resb 2048 idt_end: idt_temp: resb 8