mpx386.s

MINIX2.0操作系统源码 MINIX2.0操作系统源码

!*===========================================================================*
! Note this is a macro, it looks like a subroutine.
#define hwint_slave(irq)	\
	call	save			/* save interrupted process state */;\
	inb	INT2_CTLMASK						    ;\
	orb	al, [1<<[irq-8]]					    ;\
	outb	INT2_CTLMASK		/* disable the irq		  */;\
	movb	al, ENABLE						    ;\
	outb	INT_CTL			/* reenable master 8259		  */;\
	jmp	.+2			/* delay			  */;\
	outb	INT2_CTL		/* reenable slave 8259		  */;\
	sti				/* enable interrupts		  */;\
	push	irq			/* irq				  */;\
	call	(_irq_table + 4*irq)	/* eax = (*irq_table[irq])(irq)   */;\
	pop	ecx							    ;\
	cli				/* disable interrupts		  */;\
	test	eax, eax		/* need to reenable irq?	  */;\
	jz	0f							    ;\
	inb	INT2_CTLMASK						    ;\
	andb	al, ~[1<<[irq-8]]					    ;\
	outb	INT2_CTLMASK		/* enable the irq		  */;\
0:	ret				/* restart (another) process      */

! Each of these entry points is an expansion of the hwint_slave macro
	.align	16
_hwint08:		! Interrupt routine for irq 8 (realtime clock)
	hwint_slave(8)

	.align	16
_hwint09:		! Interrupt routine for irq 9 (irq 2 redirected)
	hwint_slave(9)

	.align	16
_hwint10:		! Interrupt routine for irq 10
	hwint_slave(10)

	.align	16
_hwint11:		! Interrupt routine for irq 11
	hwint_slave(11)

	.align	16
_hwint12:		! Interrupt routine for irq 12
	hwint_slave(12)

	.align	16
_hwint13:		! Interrupt routine for irq 13 (FPU exception)
	hwint_slave(13)

	.align	16
_hwint14:		! Interrupt routine for irq 14 (AT winchester)
	hwint_slave(14)

	.align	16
_hwint15:		! Interrupt routine for irq 15
	hwint_slave(15)

!*===========================================================================*
!*				save					     *
!*===========================================================================*
! Save for protected mode.
! This is much simpler than for 8086 mode, because the stack already points
! into the process table, or has already been switched to the kernel stack.

	.align	16
save:
	cld			! set direction flag to a known value
	pushad			! save "general" registers
    o16	push	ds		! save ds
    o16	push	es		! save es
    o16	push	fs		! save fs
    o16	push	gs		! save gs
	mov	dx, ss		! ss is kernel data segment
	mov	ds, dx		! load rest of kernel segments
	mov	es, dx		! kernel does not use fs, gs
	mov	eax, esp	! prepare to return
	incb	(_k_reenter)	! from -1 if not reentering
	jnz	set_restart1	! stack is already kernel stack
	mov	esp, k_stktop
	push	_restart	! build return address for int handler
	xor	ebp, ebp	! for stacktrace
	jmp	RETADR-P_STACKBASE(eax)

	.align	4
set_restart1:
	push	restart1
	jmp	RETADR-P_STACKBASE(eax)

!*===========================================================================*
!*				_s_call					     *
!*===========================================================================*
	.align	16
_s_call:
_p_s_call:
	cld			! set direction flag to a known value
	sub	esp, 6*4	! skip RETADR, eax, ecx, edx, ebx, est
	push	ebp		! stack already points into proc table
	push	esi
	push	edi
    o16	push	ds
    o16	push	es
    o16	push	fs
    o16	push	gs
	mov	dx, ss
	mov	ds, dx
	mov	es, dx
	incb	(_k_reenter)
	mov	esi, esp	! assumes P_STACKBASE == 0
	mov	esp, k_stktop
	xor	ebp, ebp	! for stacktrace
				! end of inline save
	sti			! allow SWITCHER to be interrupted
				! now set up parameters for sys_call()
	push	ebx		! pointer to user message
	push	eax		! src/dest
	push	ecx		! SEND/RECEIVE/BOTH
	call	_sys_call	! sys_call(function, src_dest, m_ptr)
				! caller is now explicitly in proc_ptr
	mov	AXREG(esi), eax	! sys_call MUST PRESERVE si
	cli			! disable interrupts 

! Fall into code to restart proc/task running.

!*===========================================================================*
!*				restart					     *
!*===========================================================================*
_restart:

! Flush any held-up interrupts.
! This reenables interrupts, so the current interrupt handler may reenter.
! This does not matter, because the current handler is about to exit and no
! other handlers can reenter since flushing is only done when k_reenter == 0.

	cmp	(_held_head), 0	! do fast test to usually avoid function call
	jz	over_call_unhold
	call	_unhold		! this is rare so overhead acceptable
over_call_unhold:
	mov	esp, (_proc_ptr)	! will assume P_STACKBASE == 0
	lldt	P_LDT_SEL(esp)		! enable segment descriptors for task
	lea	eax, P_STACKTOP(esp)	! arrange for next interrupt
	mov	(_tss+TSS3_S_SP0), eax	! to save state in process table
restart1:
	decb	(_k_reenter)
    o16	pop	gs
    o16	pop	fs
    o16	pop	es
    o16	pop	ds
	popad
	add	esp, 4		! skip return adr
	iretd			! continue process

!*===========================================================================*
!*				exception handlers			     *
!*===========================================================================*
_divide_error:
	push	DIVIDE_VECTOR
	jmp	exception

_single_step_exception:
	push	DEBUG_VECTOR
	jmp	exception

_nmi:
	push	NMI_VECTOR
	jmp	exception

_breakpoint_exception:
	push	BREAKPOINT_VECTOR
	jmp	exception

_overflow:
	push	OVERFLOW_VECTOR
	jmp	exception

_bounds_check:
	push	BOUNDS_VECTOR
	jmp	exception

_inval_opcode:
	push	INVAL_OP_VECTOR
	jmp	exception

_copr_not_available:
	push	COPROC_NOT_VECTOR
	jmp	exception

_double_fault:
	push	DOUBLE_FAULT_VECTOR
	jmp	errexception

_copr_seg_overrun:
	push	COPROC_SEG_VECTOR
	jmp	exception

_inval_tss:
	push	INVAL_TSS_VECTOR
	jmp	errexception

_segment_not_present:
	push	SEG_NOT_VECTOR
	jmp	errexception

_stack_exception:
	push	STACK_FAULT_VECTOR
	jmp	errexception

_general_protection:
	push	PROTECTION_VECTOR
	jmp	errexception

_page_fault:
	push	PAGE_FAULT_VECTOR
	jmp	errexception

_copr_error:
	push	COPROC_ERR_VECTOR
	jmp	exception

!*===========================================================================*
!*				exception				     *
!*===========================================================================*
! This is called for all exceptions which do not push an error code.

	.align	16
exception:
 sseg	mov	(trap_errno), 0		! clear trap_errno
 sseg	pop	(ex_number)
	jmp	exception1

!*===========================================================================*
!*				errexception				     *
!*===========================================================================*
! This is called for all exceptions which push an error code.

	.align	16
errexception:
 sseg	pop	(ex_number)
 sseg	pop	(trap_errno)
exception1:				! Common for all exceptions.
	push	eax			! eax is scratch register
	mov	eax, 0+4(esp)		! old eip
 sseg	mov	(old_eip), eax
	movzx	eax, 4+4(esp)		! old cs
 sseg	mov	(old_cs), eax
	mov	eax, 8+4(esp)		! old eflags
 sseg	mov	(old_eflags), eax
	pop	eax
	call	save
	push	(old_eflags)
	push	(old_cs)
	push	(old_eip)
	push	(trap_errno)
	push	(ex_number)
	call	_exception		! (ex_number, trap_errno, old_eip,
					!	old_cs, old_eflags)
	add	esp, 5*4
	cli
	ret

!*===========================================================================*
!*				level0_call				     *
!*===========================================================================*
_level0_call:
	call	save
	jmp	(_level0_func)

!*===========================================================================*
!*				idle_task				     *
!*===========================================================================*
_idle_task:			! executed when there is no work
	jmp	_idle_task	! a "hlt" before this fails in protected mode

!*===========================================================================*
!*				data					     *
!*===========================================================================*
! These declarations assure that storage will be allocated at the very 
! beginning of the kernel data section, so the boot monitor can be easily 
! told how to patch these locations. Note that the magic number is put
! here by the compiler, but will be read by, and then overwritten by,
! the boot monitor. When the kernel starts the sizes array will be
! found here, as if it had been initialized by the compiler.

.sect .rom	! Before the string table please
_sizes:				! sizes of kernel, mm, fs filled in by boot
	.data2	0x526F		! this must be the first data entry (magic #)
	.space	16*2*2-2	! monitor uses previous word and this space
				! extra space allows for additional servers
.sect .bss
k_stack:
	.space	K_STACK_BYTES	! kernel stack
k_stktop:			! top of kernel stack
	.comm	ex_number, 4
	.comm	trap_errno, 4
	.comm	old_eip, 4
	.comm	old_cs, 4
	.comm	old_eflags, 4