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Diffstat (limited to 'sysdeps/vax/memmove.s')
| -rw-r--r-- | sysdeps/vax/memmove.s | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/sysdeps/vax/memmove.s b/sysdeps/vax/memmove.s new file mode 100644 index 0000000000..8f897fa3f4 --- /dev/null +++ b/sysdeps/vax/memmove.s @@ -0,0 +1,93 @@ +/*- + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) + .asciz "@(#)memmove.s 5.1 (Berkeley) 5/15/90" +#endif /* LIBC_SCCS and not lint */ + +/* + * void *memmove(dst, src, size) + * returns dst + * + * This optimises the usual case (count < 65536) at the expense + * of some extra memory references and branches when count >= 65536. + */ + +#include "DEFS.h" + +ENTRY(memmove, 0) + movzwl $65535,r0 /* r0 = 64K (needed below) */ + movq 8(ap),r1 /* r1 = src, r2 = length */ + movl 4(ap),r3 /* r3 = dst */ + cmpl r1,r3 + bgtru 1f /* normal forward case */ + beql 2f /* equal, nothing to do */ + addl2 r2,r1 /* overlaps iff src<dst but src+len>dst */ + cmpl r1,r3 + bgtru 4f /* overlapping, must move backwards */ + subl2 r2,r1 + +1: /* move forward */ + cmpl r2,r0 + bgtru 3f /* stupid movc3 limitation */ + movc3 r2,(r1),(r3) /* move it all */ +2: + movl 4(ap),r0 /* return original dst */ + ret +3: + subl2 r0,12(ap) /* adjust length by 64K */ + movc3 r0,(r1),(r3) /* move 64K */ + movl 12(ap),r2 + decw r0 /* from 0 to 65535 */ + brb 1b /* retry */ + +4: /* move backward */ + addl2 r2,r3 +5: + cmpl r2,r0 + bgtru 6f /* stupid movc3 limitation */ + subl2 r2,r1 + subl2 r2,r3 + movc3 r2,(r1),(r3) /* move it all */ + movl 4(ap),r0 /* return original dst */ + ret +6: + subl2 r0,12(ap) /* adjust length by 64K */ + subl2 r0,r1 + subl2 r0,r3 + movc3 r0,(r1),(r3) /* move 64K */ + movl 12(ap),r2 + decw r0 + subl2 r0,r1 + subl2 r0,r3 + brb 5b |