| /******************************************************************************* |
| * |
| * 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 "strncmp.s" |
| #ifdef __PIC |
| .pic |
| #endif |
| #ifdef __PID |
| .pid |
| #endif |
| /* |
| * (c) copyright 1988,1993 Intel Corp., all rights reserved |
| */ |
| /* |
| procedure strncmp (optimized assembler version for the 80960K Series) |
| |
| result = strncmp (src1_addr, src2_addr, max_bytes) |
| |
| 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. Do not compare more than |
| max_bytes bytes. |
| |
| 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 strncmp |
| will fetch ahead. Disallowing the fetch ahead would impose |
| a severe performance penalty. |
| |
| Strategy: |
| |
| Fetch and compare the strings by words and go to a character |
| comparison loop as soon as a pair of words differ. If the |
| words are equal up through either the exhaustion of max_bytes |
| or the presence of the null byte, return 0 (equality). Otherwise, |
| the character comparator will return -1 or 1 for inequality, or |
| 0 if the differing byte is after the null byte or after the |
| exhaustion of max_bytes. |
| |
| 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. |
| */ |
| |
| .globl _strncmp |
| .globl __strncmp |
| .leafproc _strncmp,__strncmp |
| .align 2 |
| |
| _strncmp: |
| #ifndef __PIC |
| lda .Lrett,g14 |
| #else |
| lda .Lrett-(.+8)(ip),g14 |
| #endif |
| __strncmp: |
| mov g14,g13 |
| ldconst 0,g14 |
| cmpibge 0,g2,Lequal_exit # Lexit early if max_bytes <= 0 |
| addo g2,g0,g2 |
| .Lwloop: |
| cmpo g0,g2 # are max_bytes exhausted? |
| ld (g0), g5 # fetch word of source_1 |
| bge Lequal_exit # Lexit (equality) if max_bytes exhausted |
| ld (g1), g3 # fetch word of source_2 |
| addo 4,g0,g0 # post-increment source_1 ptr |
| scanbyte 0,g5 # is a null byte present? |
| addo 4,g1,g1 # post-increment source_1 ptr |
| be .Lcloop.a # perform char comparator if null byte found |
| cmpobe g5,g3,.Lwloop # perform char comparator if words are unequal |
| |
| .Lcloop.a: subo 4,g0,g0 # adjust max_byte counter |
| ldconst 0xff,g4 # byte extraction mask |
| |
| .Lcloop: and g4,g5,g7 # compare individual bytes |
| and g4,g3,g6 |
| cmpobne g7,g6,.diff # if different, return -1 or 1 |
| cmpo 0,g6 # they are equal. are they null? |
| shlo 8,g4,g4 # position mask to extract next byte |
| be Lequal_exit # if they are null, Lexit (equality) |
| addo 1,g0,g0 # is max_bytes exhausted? |
| cmpobl g0,g2,.Lcloop # if not, loop. if so, Lexit (equality) |
| |
| Lequal_exit: |
| mov 0,g0 |
| bx (g13) |
| .Lrett: |
| ret |
| .diff: bl .neg |
| mov 1,g0 |
| bx (g13) |
| |
| .neg: subi 1,0,g0 |
| .Lexit: |
| bx (g13) |
| |
| /* end of strncmp */ |