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Diffstat (limited to 'newlib/libc/machine/i960/memcpy.S')
| -rw-r--r-- | newlib/libc/machine/i960/memcpy.S | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/newlib/libc/machine/i960/memcpy.S b/newlib/libc/machine/i960/memcpy.S new file mode 100644 index 00000000000..8465e474ba5 --- /dev/null +++ b/newlib/libc/machine/i960/memcpy.S @@ -0,0 +1,160 @@ +/******************************************************************************* + * + * 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 */ |