asmstartup.s

嵌入式操作系统T-Kernel 完整代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel
 *
 *    Copyright (C) 2004 by Ken Sakamura. All rights reserved.
 *    T-Kernel is distributed under the T-License.
 *----------------------------------------------------------------------
 *
 *    Version:   1.01.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2004/6/28.
 *
 *----------------------------------------------------------------------
 */

/*
 *	@(#)asmstartup.S (crttk)
 *
 *	Driver/manager startup 
 */

#include <machine.h>
#include <tk/asm.h>

	.text
	.balign	4
	.globl	Csym(_C_startup)
	.type	Csym(_C_startup), %function
Csym(_C_startup):
	bltz	$a0, l_noinit		// Initialization sequence is performed only when ac >= 0

	lui	$t0, %hi(__data_org)	// When data area does not need to be moved,
	addiu	$t0, $t0, %lo(__data_org)
	lui	$t1, %hi(__data_start)	// OS loads
	addiu	$t1, $t1, %lo(__data_start)
	beq	$t0, $t1, l_noinit

	lui	$t2, %hi(_edata)	// initialize data area
	addiu	$t2, $t2, %lo(_edata)
	dsubu	$t3, $t2, $t1
	blez	$t3, nocopy_data
  copy_data:
	lw	$t4, 0($t0)
	daddu	$t0, $t0, 4
	sw	$t4, 0($t1)
	daddu	$t1, $t1, 4
	dsubu	$t3, $t2, $t1
	bgtz	$t3, copy_data
  nocopy_data:
	lui	$t0, %hi(__bss_start)	// clear bss area
	addiu	$t0, $t0, %lo(__bss_start)
	lui	$t1, %hi(_end)
	addiu	$t1, $t1, %lo(_end)
	dsubu	$t2, $t1, $t0
	blez	$t3, nobss
  clrbss:
	sw	$zero, 0($t0)
	daddu	$t0, $t0, 4
	bne	$t0, $t1, clrbss
  nobss:

  l_noinit:
	j	Csym(_P_startup)