142078Sbostic/*- 2*61222Sbostic * Copyright (c) 1990, 1993 3*61222Sbostic * The Regents of the University of California. All rights reserved. 442078Sbostic * 542078Sbostic * %sccs.include.redist.c% 642078Sbostic */ 742078Sbostic 842078Sbostic#if defined(LIBC_SCCS) && !defined(lint) 9*61222Sbostic .asciz "@(#)memmove.s 8.1 (Berkeley) 06/04/93" 1042078Sbostic#endif /* LIBC_SCCS and not lint */ 1142078Sbostic 1242078Sbostic/* 1342078Sbostic * void *memmove(dst, src, size) 1442078Sbostic * returns dst 1542078Sbostic * 1642078Sbostic * This optimises the usual case (count < 65536) at the expense 1742078Sbostic * of some extra memory references and branches when count >= 65536. 1842078Sbostic */ 1942078Sbostic 2042078Sbostic#include "DEFS.h" 2142078Sbostic 2242078SbosticENTRY(memmove, 0) 2342078Sbostic movzwl $65535,r0 /* r0 = 64K (needed below) */ 2442078Sbostic movq 8(ap),r1 /* r1 = src, r2 = length */ 2542078Sbostic movl 4(ap),r3 /* r3 = dst */ 2642078Sbostic cmpl r1,r3 2742078Sbostic bgtru 1f /* normal forward case */ 2842078Sbostic beql 2f /* equal, nothing to do */ 2942078Sbostic addl2 r2,r1 /* overlaps iff src<dst but src+len>dst */ 3042078Sbostic cmpl r1,r3 3142078Sbostic bgtru 4f /* overlapping, must move backwards */ 3242078Sbostic subl2 r2,r1 3342078Sbostic 3442078Sbostic1: /* move forward */ 3542078Sbostic cmpl r2,r0 3642078Sbostic bgtru 3f /* stupid movc3 limitation */ 3742078Sbostic movc3 r2,(r1),(r3) /* move it all */ 3842078Sbostic2: 3942078Sbostic movl 4(ap),r0 /* return original dst */ 4042078Sbostic ret 4142078Sbostic3: 4242078Sbostic subl2 r0,12(ap) /* adjust length by 64K */ 4342078Sbostic movc3 r0,(r1),(r3) /* move 64K */ 4442078Sbostic movl 12(ap),r2 4542078Sbostic decw r0 /* from 0 to 65535 */ 4642078Sbostic brb 1b /* retry */ 4742078Sbostic 4842078Sbostic4: /* move backward */ 4942078Sbostic addl2 r2,r3 5042078Sbostic5: 5142078Sbostic cmpl r2,r0 5242078Sbostic bgtru 6f /* stupid movc3 limitation */ 5342078Sbostic subl2 r2,r1 5442078Sbostic subl2 r2,r3 5542078Sbostic movc3 r2,(r1),(r3) /* move it all */ 5642078Sbostic movl 4(ap),r0 /* return original dst */ 5742078Sbostic ret 5842078Sbostic6: 5942078Sbostic subl2 r0,12(ap) /* adjust length by 64K */ 6042078Sbostic subl2 r0,r1 6142078Sbostic subl2 r0,r3 6242078Sbostic movc3 r0,(r1),(r3) /* move 64K */ 6342078Sbostic movl 12(ap),r2 6442078Sbostic decw r0 6542078Sbostic subl2 r0,r1 6642078Sbostic subl2 r0,r3 6742078Sbostic brb 5b 68