1/*
2 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * @OSF_COPYRIGHT@
30 *
31 */
32
33#include <ppc/asm.h>
34#include <ppc/proc_reg.h>
35
36#
37# void setbit(int bitno, int *s)
38#
39# Set indicated bit in bit string.
40#     Note:	being big-endian, bit 0 is 0x80000000.
41
42ENTRY(setbit,TAG_NO_FRAME_USED)
43
44	rlwinm		r8,r3,29,3,31		/* Get byte displacement */
45	rlwinm		r9,r3,0,29,31		/* Get bit within byte */
46	li			r6,0x80				/* Start with bit 0 */
47	lbzx		r5,r4,r8			/* Grab target byte */
48	srw			r6,r6,r9			/* Get the right bit (fits right into the load cycle) */
49	or			r5,r5,r6			/* Turn on the right bit */
50	stbx		r5,r4,r8			/* Save the byte back */
51	blr
52
53#
54# void clrbit(int bitno, int *s)
55#
56# Clear indicated bit in bit string.
57#     Note:	being big-endian, bit 0 is 0x80000000.
58
59ENTRY(clrbit,TAG_NO_FRAME_USED)
60
61	rlwinm		r8,r3,29,3,31		/* Get byte displacement */
62	rlwinm		r9,r3,0,29,31		/* Get bit within byte */
63	li			r6,0x80				/* Start with bit 0 */
64	lbzx		r5,r4,r8			/* Grab target byte */
65	srw			r6,r6,r9			/* Get the right bit (fits right into the load cycle) */
66	andc		r5,r5,r6			/* Turn off the right bit */
67	stbx		r5,r4,r8			/* Save the byte back */
68	blr
69
70
71# /*
72#  * Find first bit set in bit string.
73#  */
74# int
75# ffsbit(int *s)
76#
77# Returns the bit index of the first bit set (starting from 0)
78# Assumes pointer is word-aligned
79
80ENTRY(ffsbit, TAG_NO_FRAME_USED)
81	lwz	r0,	0(ARG0)
82		mr	ARG1,	ARG0	/* Free up ARG0 for result */
83
84	cmpwi	r0,	0		/* Check against zero... */
85		cntlzw	ARG0,	r0	/* Free inst... find the set bit... */
86	bnelr+				/* Return if bit in first word */
87
88.L_ffsbit_lp:
89	lwz	r0,	4(ARG1)
90	addi	ARG1,	ARG1,	4
91	cmpwi	r0,	0		/* Check against zero... */
92		cntlzw	r12,	r0
93		add	ARG0,	ARG0,	r12	/* ARG0 keeps bit count */
94	beq+	.L_ffsbit_lp
95	blr
96
97/*
98 * int tstbit(int bitno, int *s)
99 *
100 * Test indicated bit in bit string.
101 *	Note:	 being big-endian, bit 0 is 0x80000000.
102 */
103
104ENTRY2(tstbit, testbit, TAG_NO_FRAME_USED)
105
106	rlwinm		r8,r3,29,3,31		/* Get byte displacement */
107	rlwinm		r9,r3,0,29,31		/* Get bit within byte */
108	lbzx		r5,r4,r8			/* Grab target byte */
109	addi		r9,r9,25			/* Get actual shift value */
110	rlwnm		r3,r5,r9,31,31		/* Pass the bit back */
111	blr
112