From 8a0efa53e44919bcf5ccb1d3353618a82afdf8bc Mon Sep 17 00:00:00 2001 From: Christopher Faylor Date: Thu, 17 Feb 2000 19:39:52 +0000 Subject: import newlib-2000-02-17 snapshot --- newlib/libc/machine/i960/strcmp.S | 118 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 118 insertions(+) create mode 100644 newlib/libc/machine/i960/strcmp.S (limited to 'newlib/libc/machine/i960/strcmp.S') diff --git a/newlib/libc/machine/i960/strcmp.S b/newlib/libc/machine/i960/strcmp.S new file mode 100644 index 000000000..c0cd4bd6f --- /dev/null +++ b/newlib/libc/machine/i960/strcmp.S @@ -0,0 +1,118 @@ +/******************************************************************************* + * + * 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 "strcmp.s" +#ifdef __PIC + .pic +#endif +#ifdef __PID + .pid +#endif +/* + * (c) copyright 1988,1993 Intel Corp., all rights reserved + */ +/* + procedure strcmp (optimized assembler version for the 80960K Series) + + result = strcmp (src1_addr, src2_addr) + + compare the null terminated string pointed to by src1_addr to + the string pointed to by src2_addr. Return 0 iff the strings + are equal, -1 if src1_addr is lexicographically less than src2_addr, + and 1 if it is lexicographically greater. + + Undefined behavior will occur if the end of either source string + (i.e. the terminating null byte) is in the last two words of the + program's allocated memory space. This is so because strcmp fetches + ahead. Disallowing the fetch ahead would impose a severe performance + penalty. + + Strategy: + + Fetch the source strings by words and compare the words until either + differing words are found or the null byte is encountered. In either + case, move through the word until either the differing byte if found, + in which case return -1 or 1 appropriately; or the null byte is + encountered, in which case, return zero (equality). + + Tactics: + + 1) Do NOT try to fetch 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 many source + strings will be word aligned to begin with. +*/ + + .globl _strcmp + .globl __strcmp + .leafproc _strcmp,__strcmp + .align 2 + +_strcmp: +#ifndef __PIC + lda .Lrett,g14 +#else + lda .Lrett-(.+8)(ip),g14 +#endif +__strcmp: + ld (g0), g5 # fetch first word of source_1 + mov g14,g7 # preserve return address + ldconst 0,g14 # conform to register conventions + ldconst 0xff,g4 # byte extraction mask +.Lwloop: + addo 4,g0,g0 # post-increment source_1 byte ptr + ld (g1), g3 # fetch word of source_2 + scanbyte 0,g5 # does word have a null byte? + mov g5,g2 # save a copy of the source_1 word + be .Lcloop # branch if null byte encountered + cmpo g2,g3 # are the source words the same? + addo 4,g1,g1 # post-increment source_2 byte ptr + ld (g0), g5 # fetch ahead next word of source_1 + be .Lwloop # fall thru if words are unequal + +.Lcloop: and g4,g2,g5 # extract and compare individual bytes + and g4,g3,g6 + cmpobne g5,g6,.diff # if they differ, go return 1 or -1 + cmpo 0,g6 # they are the same. Are they null? + shlo 8,g4,g4 # position mask for next extraction + bne .Lcloop # loop if null not encountered + + mov 0,g0 # return equality + bx (g7) +.Lrett: + ret +.diff: bl .neg + mov 1,g0 + bx (g7) +.neg: subi 1,0,g0 +.Lexit: + bx (g7) -- cgit v1.2.3