diff options
author | Theo de Raadt <deraadt@cvs.openbsd.org> | 1995-10-18 08:53:40 +0000 |
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committer | Theo de Raadt <deraadt@cvs.openbsd.org> | 1995-10-18 08:53:40 +0000 |
commit | d6583bb2a13f329cf0332ef2570eb8bb8fc0e39c (patch) | |
tree | ece253b876159b39c620e62b6c9b1174642e070e /lib/libc/arch/sparc/string/bzero.S |
initial import of NetBSD tree
Diffstat (limited to 'lib/libc/arch/sparc/string/bzero.S')
-rw-r--r-- | lib/libc/arch/sparc/string/bzero.S | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/lib/libc/arch/sparc/string/bzero.S b/lib/libc/arch/sparc/string/bzero.S new file mode 100644 index 00000000000..b9a5528cfc0 --- /dev/null +++ b/lib/libc/arch/sparc/string/bzero.S @@ -0,0 +1,146 @@ +/* + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This software was developed by the Computer Systems Engineering group + * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and + * contributed to Berkeley. + * + * 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. + * + * from: Header: bzero.s,v 1.1 92/06/25 12:52:46 torek Exp + * $Id: bzero.S,v 1.1 1995/10/18 08:41:41 deraadt Exp $ + */ + +#if defined(LIBC_SCCS) && !defined(lint) + .asciz "@(#)bzero.s 8.1 (Berkeley) 6/4/93" +#endif /* LIBC_SCCS and not lint */ + +#include "DEFS.h" + +/* + * bzero(addr, len) + * + * We should unroll the loop, but at the moment this would + * gain nothing since the `std' instructions are what limits us. + */ +ENTRY(bzero) + ! %o0 = addr, %o1 = len + + ! Optimize a common case: addr and len are both multiples of 8. + or %o0, %o1, %o2 + btst 7, %o2 ! ((addr | len) & 7) != 0? + bnz 1f ! if so, cannot optimize + clr %g1 ! in any case, we want g1=0 + + /* `Good' operands, can just store doubles. */ +0: + deccc 8, %o1 ! while ((len -= 8) >= 0) + bge,a 0b + std %g0, [%o0 + %o1] ! *(quad *)(addr + len) = 0; + retl + nop + + /* + * Either the address is unaligned, or the count is not a + * multiple of 8, or both. We will have to align the address + * in order to use anything `better' than stb. + */ +1: + cmp %o1, 15 ! len >= 15? + bge,a Lstd ! yes, use std + btst 1, %o0 ! (but first check alignment) + + ! not enough to bother: do byte-at-a-time loop. +2: + deccc %o1 ! while (--len >= 0) + bge,a 2b + stb %g0, [%o0 + %o1] ! addr[len] = 0; + retl + nop + +Lstd: + /* + * There are at least 15 bytes to zero. + * We may have to zero some initial stuff to align + * the address. + */ + bz,a 1f ! if (addr & 1) { + btst 2, %o0 + stb %g0, [%o0] ! *addr = 0; + inc %o0 ! addr++; + dec %o1 ! len--; + btst 2, %o0 ! } +1: + bz,a 1f ! if (addr & 2) { + btst 4, %o0 + sth %g0, [%o0] ! *(short *)addr = 0; + inc 2, %o0 ! addr += 2; + dec 2, %o1 ! len -= 2; + btst 4, %o0 ! } +1: + bz 1f ! if (addr & 4) { + dec 8, %o1 + st %g0, [%o0] ! *(int *)addr = 0; + inc 4, %o0 ! addr += 4; + dec 4, %o1 ! len -= 4; + ! } + /* + * Address is double word aligned; len is 8 less than + * the number of bytes remaining (i.e., len is 0 if + * the remaining count is 8, 1 if it is 9, etc.). + */ +1: + std %g0, [%o0] ! do { +2: ! *(quad *)addr = 0; + inc 8, %o0 ! addr += 8; + deccc 8, %o1 ! } while ((len -= 8) >= 0); + bge,a 2b + std %g0, [%o0] + + /* + * Len is in [-8..-1] where -8 => done, -7 => 1 byte to zero, + * -6 => two bytes, etc. Mop up this remainder, if any. + */ + btst 4, %o1 + bz 1f ! if (len & 4) { + btst 2, %o1 + st %g0, [%o0] ! *(int *)addr = 0; + inc 4, %o0 ! addr += 4; +1: + bz 1f ! if (len & 2) { + btst 1, %o1 + sth %g0, [%o0] ! *(short *)addr = 0; + inc 2, %o0 ! addr += 2; +1: + bnz,a 1f ! if (len & 1) + stb %g0, [%o0] ! *addr = 0; +1: + retl + nop |