1/******************************************************************************* 2 * 3 * Copyright (c) 1993 Intel Corporation 4 * 5 * Intel hereby grants you permission to copy, modify, and distribute this 6 * software and its documentation. Intel grants this permission provided 7 * that the above copyright notice appears in all copies and that both the 8 * copyright notice and this permission notice appear in supporting 9 * documentation. In addition, Intel grants this permission provided that 10 * you prominently mark as "not part of the original" any modifications 11 * made to this software or documentation, and that the name of Intel 12 * Corporation not be used in advertising or publicity pertaining to 13 * distribution of the software or the documentation without specific, 14 * written prior permission. 15 * 16 * Intel Corporation provides this AS IS, WITHOUT ANY WARRANTY, EXPRESS OR 17 * IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY 18 * OR FITNESS FOR A PARTICULAR PURPOSE. Intel makes no guarantee or 19 * representations regarding the use of, or the results of the use of, 20 * the software and documentation in terms of correctness, accuracy, 21 * reliability, currentness, or otherwise; and you rely on the software, 22 * documentation and results solely at your own risk. 23 * 24 * IN NO EVENT SHALL INTEL BE LIABLE FOR ANY LOSS OF USE, LOSS OF BUSINESS, 25 * LOSS OF PROFITS, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES 26 * OF ANY KIND. IN NO EVENT SHALL INTEL'S TOTAL LIABILITY EXCEED THE SUM 27 * PAID TO INTEL FOR THE PRODUCT LICENSED HEREUNDER. 28 * 29 ******************************************************************************/ 30 31 .file "memcpy.s" 32#ifdef __PIC 33 .pic 34#endif 35#ifdef __PID 36 .pid 37#endif 38/* 39 * (c) copyright 1988,1993 Intel Corp., all rights reserved 40 */ 41/* 42 procedure memmove (optimized assembler version for the 80960K series) 43 procedure memcpy (optimized assembler version for the 80960K series) 44 45 dest_addr = memmove (dest_addr, src_addr, len) 46 dest_addr = memcpy (dest_addr, src_addr, len) 47 48 copy len bytes pointed to by src_addr to the space pointed to by 49 dest_addr. Return the original dest_addr. 50 51 These routines will work even if the arrays overlap. The standard 52 requires this of memmove, but memcpy is allowed to fail if overlap 53 is present. Nevertheless, it is implemented the same as memmove 54 because the overhead is trifling. 55 56 Undefined behavior will occur if the end of the source array is in 57 the last two words of the program's allocated memory space. This 58 is so because the routine fetches ahead. Disallowing the fetch 59 ahead would impose a severe performance penalty. 60 61 Strategy: 62 63 Fetch the source array by words and store them by words to the 64 destination array, until there are fewer than three bytes left 65 to copy. Then, using the last word of the source (the one that 66 contains the remaining 0, 1, 2, or 3 bytes to be copied), store 67 a byte at a time until Ldone. 68 69 Tactics: 70 71 1) Do NOT try to fetch and store the words in a word aligned manner 72 because, in my judgement, the performance degradation experienced due 73 to non-aligned accesses does NOT outweigh the time and complexity added 74 by the preamble and convoluted body that would be necessary to assure 75 alignment. This is supported by the intuition that most source and 76 destination arrays (even more true of most big source arrays) will 77 be word aligned to begin with. 78 79 2) For non-overlapping arrays, rather than decrementing len to zero, 80 I calculate the address of the byte after the last byte of the 81 destination array, and quit when the destination byte pointer passes 82 that. 83 84 3) For overlapping arrays where the source starts at a lower address 85 than the destination the move is performed in reverse order. 86 87 4) Overlapping arrays where the source starts at a higher address 88 are treated like non-overlapping case. Where the two arrays exactly 89 coincide, the routine is short-circuited; no move is Ldone at all. 90 This costs only one cycle. 91*/ 92 93 .globl _memcpy, _memmove 94 .globl __memcpy, __memmove 95 .leafproc _memmove, __memmove 96 .leafproc _memcpy, __memcpy 97 .align 2 98_memmove: 99_memcpy: 100#ifndef __PIC 101 lda Lrett,g14 102#else 103 lda Lrett-(.+8)(ip),g14 104#endif 105__memmove: 106__memcpy: 107 mov g14, g13 # preserve return address 108 cmpibge 0,g2,Lexit # exit if number of bytes to move is <= zero. 109 cmpo g0,g1 # does start of dest overlap end of src? 110 addo g2,g1,g3 111 be Lexit # no move necessary if src and dest are same 112 concmpo g3,g0 113 addo g2, g0, g6 114 bg Lbackwards # if overlap, then do move backwards 115 116 ld (g1), g7 # fetch first word of source 117 mov g0, g5 118 b Lwloop_b 119 120Lwloop_a: 121 ld (g1), g7 # fetch ahead next word of source 122 st g4, (g5) # store word to dest 123 addo 4, g5, g5 # post-increment dest pointer 124Lwloop_b: # word copying loop 125 addo 4, g1, g1 # pre-increment src pointer 126 cmpo g3, g1 # is len <= 3 ? 127 mov g7, g4 # keep a copy of the current word 128 bge Lwloop_a # loop if more than 3 bytes to move 129 cmpobe g6, g5, Lexit # quit if no more bytes to move 130 131Lcloop_a: # character copying loop (len < 3) 132 stob g4, (g5) # store a byte 133 shro 8, g4, g4 # position next byte for storing 134 addo 1, g5, g5 135 cmpobne g6, g5, Lcloop_a # quit if no more bytes to move 136 137Lexit: 138 mov 0, g14 139 bx (g13) # g0 = dest array address; g14 = 0 140Lrett: 141 ret 142 143Lwloop.a: 144 subo 4, g6, g6 # pre-decrement dest pointer 145 st g7, (g6) # store word to dest 146Lbackwards: # word copying loop 147 subo 4, g3, g3 # pre-decrement src pointer 148 cmpo g1, g3 # is len <= 3? 149 ld (g3), g7 # fetch ahead next word of source 150 ble Lwloop.a # loop if more than 3 bytes to move 151 cmpobe g6, g0, Lexit # quit if no more bytes to move 152 153Lcloop.a: 154 subo 1, g6, g6 155 rotate 8, g7, g7 # position byte for storing 156 stob g7, (g6) # store byte 157 cmpobne g6, g0, Lcloop.a # quit if no more bytes to move 158 b Lexit 159 160/* end of memmove */ 161
