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vr_idle.S revision 1.12 
      1 /*	$NetBSD: vr_idle.S,v 1.12 2007/05/11 12:56:01 tsutsui Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Digital Equipment Corporation and Ralph Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  * Copyright (C) 1989 Digital Equipment Corporation.
     35  * Permission to use, copy, modify, and distribute this software and
     36  * its documentation for any purpose and without fee is hereby granted,
     37  * provided that the above copyright notice appears in all copies.
     38  * Digital Equipment Corporation makes no representations about the
     39  * suitability of this software for any purpose.  It is provided "as is"
     40  * without express or implied warranty.
     41  *
     42  */
     43 
     44 #include <mips/asm.h>
     45 #include <mips/cpuregs.h>
     46 #include <hpcmips/vr/vr_asm.h>
     47 
     48 #include "opt_lockdebug.h"
     49 
     50 #include "assym.h"
     51 
     52 	.set	noreorder
     53 
     54 /*
     55  * When no processes are on the runq, cpu_switch branches to idle
     56  * to wait for something to come ready.
     57  * Note: this is really a part of cpu_switch() but defined here for kernel
     58  * profiling.
     59  */
     60 LEAF(vr_idle)
     61 	sw	zero, _C_LABEL(curlwp)		# set curlwp NULL for stats
     62 	jal	_C_LABEL(sched_unlock_idle)	# release sched_lock
     63 	nop
     64 	li	t0, (MIPS_INT_MASK | MIPS_SR_INT_IE)
     65 	mtc0	t0, MIPS_COP_0_STATUS		# enable all interrupts
     66 	nop
     67 
     68 	/* Try to zero some free pages. */
     69 	lbu	t0, _C_LABEL(uvm) + UVM_PAGE_IDLE_ZERO
     70 	nop
     71 	beq	t0, zero, 1f
     72 	nop
     73 	jal	_C_LABEL(uvm_pageidlezero)
     74 	nop
     75 1:
     76 	lw	t0, _C_LABEL(sched_whichqs)	# look for non-empty queue
     77 	bne	t0, zero, 1f
     78 	nop
     79 	.word	VR_OPCODE_STANDBY
     80 	nop
     81 	nop
     82 	nop
     83 	nop
     84 	beq	t0, zero, 1b
     85 	nop
     86 1:
     87 	mtc0	zero, MIPS_COP_0_STATUS		# disable all interrupts
     88 	nop
     89 	nop
     90 	nop
     91 	nop
     92 	jal	_C_LABEL(sched_lock_idle)	# acquire sched_lock
     93 	nop
     94 	la	ra, cpu_switch_queuescan	# rathole to cpu_switch()
     95 	j	ra
     96 	nop
     97 END(vr_idle)
     98