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Diffstat (limited to 'newlib/libc/machine/i960/memccpy.S')
| -rw-r--r-- | newlib/libc/machine/i960/memccpy.S | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/newlib/libc/machine/i960/memccpy.S b/newlib/libc/machine/i960/memccpy.S new file mode 100644 index 00000000000..df1947228b8 --- /dev/null +++ b/newlib/libc/machine/i960/memccpy.S @@ -0,0 +1,143 @@ +/******************************************************************************* + * + * 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 "memccpy.s" +#ifdef __PIC + .pic +#endif +#ifdef __PID + .pid +#endif +/* + * (c) copyright 1989,1993 Intel Corp., all rights reserved + */ +/* + procedure memccpy (optimized assembler version for the 80960K series) + + dest_addr = memccpy (dest_addr, src_addr, char, len) + + copy len bytes pointed to by src_addr to the space pointed to by + dest_addr, stopping if char is copied. If char is copied, + return address of byte after char in dest string; else null. + + + 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. + + Undefined behavior will also occur if the source and destination + strings overlap. + + 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) 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. + +*/ + + .globl _memccpy + .leafproc _memccpy, __memccpy + .align 2 +_memccpy: +#ifndef __PIC + lda Lrett,g14 +#else + lda Lrett-(.+8)(ip),g14 +#endif +__memccpy: + mov g14, g13 # preserve return address + cmpibge 0,g3,Lexit_char_not_found + + addo g3,g1,g3 # compute beyond end of src + ld (g1), g7 # fetch first word of source + lda 0xff,g5 # mask for char + and g5,g2,g2 # extract only char + shlo 8,g2,g6 + or g2,g6,g6 + shlo 16,g6,g4 + or g6,g4,g6 # word of char + b Lwloop_b + +Lwloop_a: + ld (g1), g7 # fetch ahead next word of source + st g4, (g0) # store word to dest + addo 4, g0, g0 # 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 + bl Lcloop_setup # quit word loop if less than 4 bytes + scanbyte g6, g7 # check for char + bno Lwloop_a # continue word loop if char not found. + +Lcloop_setup: + subo 4, g1, g1 # back down src pointer + cmpobe g1, g3, Lexit_char_not_found + +Lcloop_a: # character copying loop (len < 3) + and g5,g4,g7 # check the byte against char + cmpo g7,g2 + stob g7,(g0) # store the byte + addo 1, g0, g0 + be Lexit_char_found + addo 1,g1,g1 + cmpo g1,g3 + shro 8,g4,g4 # position next byte + bne Lcloop_a + +Lexit_char_not_found: + mov 0, g0 +Lexit_char_found: + lda 0,g14 + bx (g13) # g0 = dest array address; g14 = 0 +Lrett: + ret + + +/* end of memccpy */ |