diff options
Diffstat (limited to 'lib/libc/mips/string/bzero.S')
| -rw-r--r-- | lib/libc/mips/string/bzero.S | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/libc/mips/string/bzero.S b/lib/libc/mips/string/bzero.S new file mode 100644 index 0000000..cb5d258 --- /dev/null +++ b/lib/libc/mips/string/bzero.S @@ -0,0 +1,74 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Ralph Campbell. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <machine/asm.h> + +#if defined(LIBC_SCCS) + .text + .asciz "$OpenBSD$" +#endif /* LIBC_SCCS */ + +/* bzero(s1, n) */ + +LEAF(bzero) + .set noreorder + blt a1, 12, smallclr # small amount to clear? + subu a3, zero, a0 # compute # bytes to word align address + and a3, a3, 3 + beq a3, zero, 1f # skip if word aligned + subu a1, a1, a3 # subtract from remaining count + SWHI zero, 0(a0) # clear 1, 2, or 3 bytes to align + addu a0, a0, a3 +1: + and v0, a1, 3 # compute number of words left + subu a3, a1, v0 + move a1, v0 + addu a3, a3, a0 # compute ending address +2: + addu a0, a0, 4 # clear words + bne a0, a3, 2b # unrolling loop doesnt help + sw zero, -4(a0) # since we are limited by memory speed +smallclr: + ble a1, zero, 2f + addu a3, a1, a0 # compute ending address +1: + addu a0, a0, 1 # clear bytes + bne a0, a3, 1b + sb zero, -1(a0) +2: + j ra + nop +END(bzero) |
