ctxsw.s,v

来自「TCP-IP红宝书源代码」· S,V 代码 · 共 73 行

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date	97.09.21.19.29.30;	author dls;	state Dist;
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1.1
date	94.05.06.03.12.23;	author dls;	state Works;
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@pre-3e code
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@/* ctxsw.s - ctxsw */

		.text
		.globl	_ctxsw
newmask:	.word	0

/*------------------------------------------------------------------------
 * ctxsw -  call is ctxsw(&oldsp, &oldmask, &newsp, &newmask)
 *------------------------------------------------------------------------
 */
_ctxsw:
		pushl	%ebp
		movl	%esp,%ebp

		pushl	12(%ebp)
		call	_disable
		movl	20(%ebp),%eax
		movw	(%eax),%dx
		movw	%dx,newmask
		pushfl			/* save flags */
		pushal			/* save general regs */
		/* save segment registers here, if multiple allowed */
		movl	8(%ebp),%eax
		movl	%esp,(%eax)	/* save old SP */

		movl	16(%ebp),%eax
		movl	(%eax),%esp	/* restore new SP */
		/* restore new segment registers here, if multiple allowed */
		popal			/* restore general registers */
		popfl			/* restore flags */
		pushl	$newmask
		call	_restore
		leave
		ret

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@Initial revision
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