2 * Copyright 2000 Brian S. Dean <bsd@bsdhome.com>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY BRIAN S. DEAN ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BRIAN S. DEAN BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
21 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
22 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
23 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
31 * $FreeBSD: src/lib/libc/i386/sys/i386_set_watch.c,v 1.1.2.1 2000/10/21 01:33:34 bsd Exp $
32 * $DragonFly: src/lib/libc/i386/sys/i386_set_watch.c,v 1.2 2003/06/17 04:26:43 dillon Exp $
36 #include <machine/reg.h>
37 #include <machine/sysarch.h>
41 i386_set_watch(int watchnum, unsigned int watchaddr, int size,
42 int access, struct dbreg * d)
48 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
49 if ((d->dr7 & mask) == 0)
59 size = 1; /* size must be 1 for an execution breakpoint */
61 case DBREG_DR7_WRONLY:
64 default : return -1; break;
68 * we can watch a 1, 2, or 4 byte sized location
71 case 1 : mask = 0x00; break;
72 case 2 : mask = 0x01 << 2; break;
73 case 4 : mask = 0x03 << 2; break;
74 default : return -1; break;
79 /* clear the bits we are about to affect */
80 d->dr7 &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
82 /* set drN register to the address, N=watchnum */
83 DBREG_DRX(d,watchnum) = watchaddr;
85 /* enable the watchpoint */
86 d->dr7 |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16));