projects / apple / xnu.git / blame
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|---|---|---|
| 1c79356b A |
1 | /* |
| 2 | * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 2d21ac55 | 4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
| 1c79356b | 5 | * |
| 2d21ac55 A |
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. | |
| 8f6c56a5 | 14 | * |
| 2d21ac55 A |
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 | |
| 8f6c56a5 A |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 2d21ac55 A |
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. | |
| 8f6c56a5 | 25 | * |
| 2d21ac55 | 26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
| 1c79356b A |
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 | ||
| 42 | ENTRY(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 | ||
| 59 | ENTRY(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 | ||
| 80 | ENTRY(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 | ||
| 104 | ENTRY2(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 |