116 lines
3.9 KiB
C
116 lines
3.9 KiB
C
/*
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(C) Copyright 2001,2006,
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International Business Machines Corporation,
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Sony Computer Entertainment, Incorporated,
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Toshiba Corporation,
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the names of the copyright holders nor the names of their
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contributors may be used to endorse or promote products derived from this
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software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <spu_intrinsics.h>
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#include <stddef.h>
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#include "vec_literal.h"
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/* Scans the string pointed to by s for the character c and
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* returns a pointer to the last occurance of c. If
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* c is not found, then NULL is returned.
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*/
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char * strrchr(const char *s, int c)
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{
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int nskip;
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vec_uchar16 *ptr, data, vc;
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vec_uint4 cmp_c, cmp_0, cmp;
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vec_uint4 res_ptr, res_cmp;
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vec_uint4 mask, result;
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vec_uint4 one = spu_splats(0xffffU);
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/* Scan memory array a quadword at a time. Skip leading
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* mis-aligned bytes.
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*/
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ptr = (vec_uchar16 *)s;
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nskip = -((unsigned int)(ptr) & 15);
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mask = spu_rlmask(one, nskip);
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vc = spu_splats((unsigned char)(c));
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data = *ptr++;
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ptr = (vec_uchar16 *)((unsigned int)ptr & ~15);
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cmp_c = spu_and(spu_gather(spu_cmpeq(data, vc)), mask);
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cmp_0 = spu_and(spu_gather(spu_cmpeq(data, 0)), mask);
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res_ptr = spu_splats(0U);
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res_cmp = spu_splats(0U);
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while (spu_extract(cmp_0, 0) == 0) {
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cmp = spu_cmpeq(cmp_c, 0);
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res_ptr = spu_sel(spu_promote((unsigned int)(ptr), 0), res_ptr, cmp);
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res_cmp = spu_sel(cmp_c, res_cmp, cmp);
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data = *ptr++;
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cmp_c = spu_gather(spu_cmpeq(data, vc));
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cmp_0 = spu_gather(spu_cmpeq(data, 0));
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cmp = spu_cmpeq(cmp_c, 0);
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}
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/* Compute the location of the last character before termination
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* character.
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*
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* First mask off compare results following the first termination character.
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*/
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mask = spu_sl(one, 31 - spu_extract(spu_cntlz(cmp_0), 0));
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cmp_c = spu_and(cmp_c, mask);
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/* Conditionally update res_ptr and res_cmd if a match was found in the last
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* quadword.
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*/
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cmp = spu_cmpeq(cmp_c, 0);
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res_ptr = spu_sel(spu_promote((unsigned int)(ptr), 0), res_ptr, cmp);
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res_cmp = spu_sel(cmp_c, res_cmp, cmp);
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/* Bit reserve res_cmp for locating last occurance.
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*/
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mask = spu_cmpeq(res_cmp, 0);
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res_cmp = (vec_uint4)spu_maskb(spu_extract(res_cmp, 0));
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res_cmp = spu_gather((vec_uchar16)spu_shuffle(res_cmp, res_cmp,
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VEC_LITERAL(vec_uchar16,
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15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0)));
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/* Compute the location (ptr) of the last occurance of c. If no
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* occurance was found (ie, element 0 of res_cmp == 0, then return
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* NULL.
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*/
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result = spu_sub(spu_add(res_ptr, 15), spu_cntlz(res_cmp));
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result = spu_andc(result, mask);
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return ((char *)spu_extract(result, 0));
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}
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