#define ASM_SOURCE 1
#include "segment.h"
.file "irq_wrappers.S"
.text

.extern exception_handler_wrap
.globl exception_handler_wrapper_array

/** Update the kernel TSS in case we are switching to a thread in user
	mode in order to come back into the correct kernel stack */
.extern cpu_context_update_kernel_tss

/* The address of the function to call to set back the user thread's
   MMU configuration upon return to user context */
.extern threadPrepareExceptionSwitchBack

.altmacro


.macro exception_mac id
    exception_wrapper_\id:
    .type exception_wrapper_\id,@function
        /* INTERRUPT FRAME START */
        /* ALREADY PUSHED TO US BY THE PROCESSOR UPON ENTRY TO THIS INTERRUPT */
        /* uint32_t flags */
        /* uint32_t cs; */
        /* uint32_t ip */
        /* Pushes the other reg to save same and look like a struct cpu_state*/
        /* Fake error code */
        pushl $0

        /* Backup the actual context */
        pushl %ebp
        movl %esp, %ebp

        pushl %eax
        pushl %ecx
        pushl %edx
        pushl %ebx
        pushl %esi
        pushl %edi
        subl  $2,%esp
        pushw %ss
        pushw %ds
        pushw %es
        pushw %fs
        pushw %gs

        /* Set correct kernel segment descriptors' value */
        movw $BUILD_SEGMENT_REG_VALUE(0, 0, SEG_KDATA), %di
        pushw %di ; popw %ds
        pushw %di ; popw %es
        pushw %di ; popw %fs
        pushw %di ; popw %gs

        push %esp
        pushl $\id
        call exception_handler_wrap
        addl $8, %esp

        /* Reconfigure the MMU if needed */
        pushl %esp /* cpu_ctxt */
        call threadPrepareExceptionSwitchBack
        addl  $4, %esp /* Unallocate the stack */

        /* Prepare kernel TSS in case we are switching to a
           user thread: we make sure that we will come back
           into the kernel at a correct stack location */
        pushl %esp /* Pass the location of the context we are
                      restoring to the function */
        call cpu_context_update_kernel_tss
        addl $4, %esp

        /* Restore the context */
        popw  %gs
        popw  %fs
        popw  %es
        popw  %ds
        popw  %ss
        addl  $2,%esp
        popl %edi
        popl %esi
        popl %ebx
        popl %edx
        popl %ecx
        popl %eax
        popl %ebp
        /* Remove fake error code */
        addl  $4, %esp

        iret
.endm

.macro exception_mac_with_errcode id
    exception_wrapper_\id:
    .type exception_wrapper_\id,@function
        /* INTERRUPT FRAME START */
        /* ALREADY PUSHED TO US BY THE PROCESSOR UPON ENTRY TO THIS INTERRUPT */
        /* uint32_t flags */
        /* uint32_t cs; */
        /* uint32_t ip */
        /* uint32_t errcode */
        /* Pushes the other reg to save same and look like a struct cpu_state*/

        /* Backup the actual context */
        pushl %ebp
        movl %esp, %ebp

        pushl %eax
        pushl %ecx
        pushl %edx
        pushl %ebx
        pushl %esi
        pushl %edi
        subl  $2,%esp
        pushw %ss
        pushw %ds
        pushw %es
        pushw %fs
        pushw %gs

        /* Set correct kernel segment descriptors' value */
        movw $BUILD_SEGMENT_REG_VALUE(0, 0, SEG_KDATA), %di
        pushw %di ; popw %ds
        pushw %di ; popw %es
        pushw %di ; popw %fs
        pushw %di ; popw %gs

        push %esp
        pushl $\id
        call exception_handler_wrap
        addl $8, %esp

        /* Reconfigure the MMU if needed */
        pushl %esp /* cpu_ctxt */
        call threadPrepareExceptionSwitchBack
        addl  $4, %esp /* Unallocate the stack */

        /* Prepare kernel TSS in case we are switching to a
           user thread: we make sure that we will come back
           into the kernel at a correct stack location */
        pushl %esp /* Pass the location of the context we are
                      restoring to the function */
        call cpu_context_update_kernel_tss
        addl $4, %esp

		/* Restore the context */
        popw  %gs
        popw  %fs
        popw  %es
        popw  %ds
        popw  %ss
        addl  $2,%esp
        popl %edi
        popl %esi
        popl %ebx
        popl %edx
        popl %ecx
        popl %eax
        popl %ebp

        /* Error code isn't compatible with iretd */
        addl $4, %esp

        iret
.endm

/* List of exception w or w/o err code https://wiki.osdev.org/Exceptions */
.irp exception_id, 8, 10, 11, 12, 13, 14, 17, 30
    exception_mac_with_errcode exception_id
.endr

.irp exception_id, 0, 1, 2, 3, 4, 5, 6, 7, 9, 15, 16, 18, 19, 20 21, 22, 23, 24, 25, 26, 27, 28, 29, 31
    exception_mac exception_id
.endr

.macro ref_exception_wrapper id
    .long exception_wrapper_\id
.endm

.section ".rodata"
.p2align 5, 0x0
exception_handler_wrapper_array:
.set i, 0x0
.rept 0x20
    ref_exception_wrapper %i
    .set i, i+1
.endr