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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Kernel debug stuff to use the Watch registers.
 * Useful to find stack overflows, dangling pointers etc.
 *
 * Copyright (C) 1995, 1996, 1999 by Ralf Baechle
 */
#include <asm/asm.h>
#include <asm/mipsregs.h>
#include <asm/regdef.h>

                .set    noreorder
/*
 * Parameter: a0 - logic address to watch
 *                 Currently only KSEG0 addresses are allowed!
 *            a1 - set bit #1 to trap on load references
 *                     bit #0 to trap on store references
 * Results  : none
 */
                LEAF(__watch_set)
                li      t0,0x80000000
                subu    a0,t0
                ori     a0,7
                xori    a0,7
                or      a0,a1
                mtc0    a0,CP0_WATCHLO
                sw      a0,watch_savelo

                jr      ra
                 mtc0   zero,CP0_WATCHHI
                END(__watch_set)

/*
 * Parameter: none
 * Results  : none
 */
                LEAF(__watch_clear)
                jr      ra
                 mtc0   zero,CP0_WATCHLO
                END(__watch_clear)

/*
 * Parameter: none
 * Results  : none
 */
                LEAF(__watch_reenable)
                lw      t0,watch_savelo
                jr      ra
                 mtc0   t0,CP0_WATCHLO
                END(__watch_reenable)

/*
 * Saved value of the c0_watchlo register for watch_reenable()
 */
                .data
watch_savelo:   .word   0
                .text