old-MTGos-old/kernel/hal/x86/asm/snippets.S

.global loadGDT
//void _stdcall loadGDT(struct gdtp* ptr);
loadGDT:
	mov 0x4(%esp), %eax // Load argument
	lgdt (%eax)
	//GDT is loaded now
	mov $0x10, %ax
	mov %ax, %ds
	mov %ax, %es
	mov %ax, %fs
	mov %ax, %gs
	mov %ax, %ss
	ljmp $0x8, $.1
.1:
	ret
.global loadIDT
//void _stdcall loadIDT(struct idtp* ptr);
loadIDT:
	mov 0x4(%esp), %eax
	lidt (%eax)
	ret
.global enterPaging
//void _stdcall enterPaging(uint32** pd);
enterPaging:
  mov 0x4(%esp), %eax
  mov %eax, %cr3
  mov %cr4, %eax
  or $0x10, %eax
  mov %eax, %cr4
  mov %cr0, %eax
  or $0x80000000, %eax
  mov %eax, %cr0
  mov (%esp), %eax
  ret

//Handle interrupts
.macro intr_stub nr
.global intr_stub_\nr
.align 16
intr_stub_\nr:
	pushl $0
	pushl $\nr
	jmp intr_common_handler
.endm
.macro intr_stub_error_code nr
.global intr_stub_\nr
.align 16
intr_stub_\nr:
	pushl $\nr
	jmp intr_common_handler
.endm
intr_stub 0
intr_stub 1
intr_stub 2
intr_stub 3
intr_stub 4
intr_stub 5
intr_stub 6
intr_stub 7
intr_stub_error_code 8
intr_stub 9
intr_stub_error_code 10
intr_stub_error_code 11
intr_stub_error_code 12
intr_stub_error_code 13
intr_stub_error_code 14
intr_stub 15
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intr_stub_error_code 17
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//This should cover everything.
.extern handleINT
intr_common_handler:
  cli
	push %ebp
	push %edi
	push %esi
	push %edx
	push %ecx
	push %ebx
	push %eax
	//Load kernel datasegs
	mov $0x10, %ax
	mov %ax, %ds
	mov %ax, %es
	mov $8, %ecx
	mov $fld_hi, %ebx
	mov $fld_lo, %edx
.storeloop:
	fstpl (%edx)
	mov (%edx), %eax
	push %eax
	mov (%ebx), %eax
	push %eax
	loop .storeloop

	push %esp
	call handleINT
	mov %eax, %esp
	mov $8, %ecx
	mov $fld_hi, %ebx
	mov $fld_lo, %edx
.loadloop:
	pop %eax
	mov %eax, (%ebx)
	pop %eax
	mov %eax, (%edx)
	fldl (%ebx)
	loop .loadloop

	//Load user datasegs
	mov $0x23, %ax
	mov %ax, %ds
	mov %ax, %es
	pop %eax
	pop %ebx
	pop %ecx
	pop %edx
	pop %esi
	pop %edi
	pop %ebp
	// Take error code and interrupt number from stack
	add $8, %esp
	// Exit interrupt
	iret

.section .data
fld_lo:
.space 4
fld_hi:
.space 4