| /******************************************************************************* |
| * |
| * Copyright (c) 1993 Intel Corporation |
| * |
| * Intel hereby grants you permission to copy, modify, and distribute this |
| * software and its documentation. Intel grants this permission provided |
| * that the above copyright notice appears in all copies and that both the |
| * copyright notice and this permission notice appear in supporting |
| * documentation. In addition, Intel grants this permission provided that |
| * you prominently mark as "not part of the original" any modifications |
| * made to this software or documentation, and that the name of Intel |
| * Corporation not be used in advertising or publicity pertaining to |
| * distribution of the software or the documentation without specific, |
| * written prior permission. |
| * |
| * Intel Corporation provides this AS IS, WITHOUT ANY WARRANTY, EXPRESS OR |
| * IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY |
| * OR FITNESS FOR A PARTICULAR PURPOSE. Intel makes no guarantee or |
| * representations regarding the use of, or the results of the use of, |
| * the software and documentation in terms of correctness, accuracy, |
| * reliability, currentness, or otherwise; and you rely on the software, |
| * documentation and results solely at your own risk. |
| * |
| * IN NO EVENT SHALL INTEL BE LIABLE FOR ANY LOSS OF USE, LOSS OF BUSINESS, |
| * LOSS OF PROFITS, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES |
| * OF ANY KIND. IN NO EVENT SHALL INTEL'S TOTAL LIABILITY EXCEED THE SUM |
| * PAID TO INTEL FOR THE PRODUCT LICENSED HEREUNDER. |
| * |
| ******************************************************************************/ |
| |
| .file "memcpy.s" |
| #ifdef __PIC |
| .pic |
| #endif |
| #ifdef __PID |
| .pid |
| #endif |
| /* |
| * (c) copyright 1988,1993 Intel Corp., all rights reserved |
| */ |
| /* |
| procedure memmove (optimized assembler version for the 80960K series) |
| procedure memcpy (optimized assembler version for the 80960K series) |
| |
| dest_addr = memmove (dest_addr, src_addr, len) |
| dest_addr = memcpy (dest_addr, src_addr, len) |
| |
| copy len bytes pointed to by src_addr to the space pointed to by |
| dest_addr. Return the original dest_addr. |
| |
| These routines will work even if the arrays overlap. The standard |
| requires this of memmove, but memcpy is allowed to fail if overlap |
| is present. Nevertheless, it is implemented the same as memmove |
| because the overhead is trifling. |
| |
| Undefined behavior will occur if the end of the source array is in |
| the last two words of the program's allocated memory space. This |
| is so because the routine fetches ahead. Disallowing the fetch |
| ahead would impose a severe performance penalty. |
| |
| Strategy: |
| |
| Fetch the source array by words and store them by words to the |
| destination array, until there are fewer than three bytes left |
| to copy. Then, using the last word of the source (the one that |
| contains the remaining 0, 1, 2, or 3 bytes to be copied), store |
| a byte at a time until Ldone. |
| |
| Tactics: |
| |
| 1) Do NOT try to fetch and store the words in a word aligned manner |
| because, in my judgement, the performance degradation experienced due |
| to non-aligned accesses does NOT outweigh the time and complexity added |
| by the preamble and convoluted body that would be necessary to assure |
| alignment. This is supported by the intuition that most source and |
| destination arrays (even more true of most big source arrays) will |
| be word aligned to begin with. |
| |
| 2) For non-overlapping arrays, rather than decrementing len to zero, |
| I calculate the address of the byte after the last byte of the |
| destination array, and quit when the destination byte pointer passes |
| that. |
| |
| 3) For overlapping arrays where the source starts at a lower address |
| than the destination the move is performed in reverse order. |
| |
| 4) Overlapping arrays where the source starts at a higher address |
| are treated like non-overlapping case. Where the two arrays exactly |
| coincide, the routine is short-circuited; no move is Ldone at all. |
| This costs only one cycle. |
| */ |
| |
| .globl _memcpy, _memmove |
| .globl __memcpy, __memmove |
| .leafproc _memmove, __memmove |
| .leafproc _memcpy, __memcpy |
| .align 2 |
| _memmove: |
| _memcpy: |
| #ifndef __PIC |
| lda Lrett,g14 |
| #else |
| lda Lrett-(.+8)(ip),g14 |
| #endif |
| __memmove: |
| __memcpy: |
| mov g14, g13 # preserve return address |
| cmpibge 0,g2,Lexit # exit if number of bytes to move is <= zero. |
| cmpo g0,g1 # does start of dest overlap end of src? |
| addo g2,g1,g3 |
| be Lexit # no move necessary if src and dest are same |
| concmpo g3,g0 |
| addo g2, g0, g6 |
| bg Lbackwards # if overlap, then do move backwards |
| |
| ld (g1), g7 # fetch first word of source |
| mov g0, g5 |
| b Lwloop_b |
| |
| Lwloop_a: |
| ld (g1), g7 # fetch ahead next word of source |
| st g4, (g5) # store word to dest |
| addo 4, g5, g5 # post-increment dest pointer |
| Lwloop_b: # word copying loop |
| addo 4, g1, g1 # pre-increment src pointer |
| cmpo g3, g1 # is len <= 3 ? |
| mov g7, g4 # keep a copy of the current word |
| bge Lwloop_a # loop if more than 3 bytes to move |
| cmpobe g6, g5, Lexit # quit if no more bytes to move |
| |
| Lcloop_a: # character copying loop (len < 3) |
| stob g4, (g5) # store a byte |
| shro 8, g4, g4 # position next byte for storing |
| addo 1, g5, g5 |
| cmpobne g6, g5, Lcloop_a # quit if no more bytes to move |
| |
| Lexit: |
| mov 0, g14 |
| bx (g13) # g0 = dest array address; g14 = 0 |
| Lrett: |
| ret |
| |
| Lwloop.a: |
| subo 4, g6, g6 # pre-decrement dest pointer |
| st g7, (g6) # store word to dest |
| Lbackwards: # word copying loop |
| subo 4, g3, g3 # pre-decrement src pointer |
| cmpo g1, g3 # is len <= 3? |
| ld (g3), g7 # fetch ahead next word of source |
| ble Lwloop.a # loop if more than 3 bytes to move |
| cmpobe g6, g0, Lexit # quit if no more bytes to move |
| |
| Lcloop.a: |
| subo 1, g6, g6 |
| rotate 8, g7, g7 # position byte for storing |
| stob g7, (g6) # store byte |
| cmpobne g6, g0, Lcloop.a # quit if no more bytes to move |
| b Lexit |
| |
| /* end of memmove */ |