projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 4a161432 | 1 | /*- |
| 1ddae302 KB |
2 | * Copyright (c) 1991, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. | |
| 4a161432 KB |
4 | * |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * Ralph Campbell. | |
| 7 | * | |
| c0567266 KB |
8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions | |
| 10 | * are met: | |
| 11 | * 1. Redistributions of source code must retain the above copyright | |
| 12 | * notice, this list of conditions and the following disclaimer. | |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright | |
| 14 | * notice, this list of conditions and the following disclaimer in the | |
| 15 | * documentation and/or other materials provided with the distribution. | |
| 16 | * 3. All advertising materials mentioning features or use of this software | |
| 17 | * must display the following acknowledgement: | |
| 18 | * This product includes software developed by the University of | |
| 19 | * California, Berkeley and its contributors. | |
| 20 | * 4. Neither the name of the University nor the names of its contributors | |
| 21 | * may be used to endorse or promote products derived from this software | |
| 22 | * without specific prior written permission. | |
| 23 | * | |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 34 | * SUCH DAMAGE. | |
| 4a161432 KB |
35 | */ |
| 36 | ||
| ad4c803f | 37 | #include <machine/machAsmDefs.h> |
| 3e6938a3 | 38 | |
| 4a161432 | 39 | #if defined(LIBC_SCCS) && !defined(lint) |
| ad787160 | 40 | ASMSTR("@(#)bzero.s 8.1 (Berkeley) 6/4/93") |
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41 | #endif /* LIBC_SCCS and not lint */ |
| 42 | ||
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43 | /* bzero(s1, n) */ |
| 44 | ||
| 45 | LEAF(bzero) | |
| 46 | .set noreorder | |
| 47 | blt a1, 12, smallclr # small amount to clear? | |
| 48 | subu a3, zero, a0 # compute # bytes to word align address | |
| 49 | and a3, a3, 3 | |
| 50 | beq a3, zero, 1f # skip if word aligned | |
| 51 | subu a1, a1, a3 # subtract from remaining count | |
| 52 | swr zero, 0(a0) # clear 1, 2, or 3 bytes to align | |
| 53 | addu a0, a0, a3 | |
| 54 | 1: | |
| 55 | and v0, a1, 3 # compute number of words left | |
| 56 | subu a3, a1, v0 | |
| 57 | move a1, v0 | |
| 58 | addu a3, a3, a0 # compute ending address | |
| 59 | 2: | |
| 60 | addu a0, a0, 4 # clear words | |
| d3f8a1f6 RC |
61 | bne a0, a3, 2b # unrolling loop doesnt help |
| 62 | sw zero, -4(a0) # since we are limited by memory speed | |
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63 | smallclr: |
| 64 | ble a1, zero, 2f | |
| 65 | addu a3, a1, a0 # compute ending address | |
| 66 | 1: | |
| 67 | addu a0, a0, 1 # clear bytes | |
| 68 | bne a0, a3, 1b | |
| 69 | sb zero, -1(a0) | |
| 70 | 2: | |
| 71 | j ra | |
| 72 | nop | |
| 73 | END(bzero) |