--- /dev/null
+/*
+ (C) Copyright 2008
+ International Business Machines Corporation,
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+ this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ * Neither the names of the copyright holders nor the names of their
+ contributors may be used to endorse or promote products derived from
+ this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <spu_intrinsics.h>
+#include "vec_literal.h"
+
+/*
+ * Supply an inline _strncpy for strcpy/cat and strncpy/cat. Relies on
+ * checklen and lastzero code being optimized out when they are constant
+ * zero values.
+ */
+static inline void * _strncpy(char * __restrict__ dest, const char *
+ __restrict__ src, size_t maxlen, int
+ checklen, int lastzero)
+{
+ int adjust, offset, soffset, doffset, shift;
+ vec_uchar16 *vsrc, *vdest;
+ vec_uchar16 sdata1, sdata2, sdata, shuffle;
+ vec_uchar16 mask1, maskzero, cmp0;
+ vec_uint4 nonzeroes, gathered_cmp, vtmp, vtmp2;
+ vec_uint4 curlen; /* assumes size_t is 4 bytes */
+ const vec_uint4 val31 = { 31, 31, 31, 31 };
+ const vec_uint4 val_0123 = { 0x00010203, 0x04050607, 0x08090A0B, 0x0C0D0E0F };
+ const vec_uchar16 all_ones = { 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff,
+ 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff };
+
+ vsrc = (vec_uchar16 *) src;
+ vdest = (vec_uchar16 *) dest;
+ soffset = (int) src & 15;
+ doffset = (int) dest & 15;
+
+ if (checklen) {
+ /*
+ * Set curlen so it is the number of bytes we would copy if starting
+ * from vdest & ~0xf.
+ *
+ * curlen could probably be replaced by comparing vdest plus some
+ * offset to dest + maxlen, that would help mainly in the while loop
+ * but would lose only one instruction (the curlen -= 16).
+ */
+ curlen = spu_splats((unsigned int) (maxlen + doffset));
+ }
+
+ /*
+ * Setup a shuffle pattern to align the source string with the
+ * alignment of the destination string.
+ */
+ vtmp = spu_cmpgt(spu_promote(doffset, 0), spu_promote(soffset, 0));
+ adjust = spu_extract(vtmp, 0);
+ offset = soffset - doffset;
+ offset += adjust & 16;
+ shuffle = spu_splats((unsigned char) offset);
+ shuffle = (vec_uchar16) spu_add((vec_uint4) shuffle, val_0123);
+
+ vsrc += adjust;
+ sdata1 = *vsrc++;
+ sdata2 = *vsrc++;
+ sdata = spu_shuffle(sdata1, sdata2, shuffle);
+
+ /*
+ * mask out leading bytes
+ */
+ mask1 = spu_rlmaskqwbyte(all_ones, -doffset);
+
+ cmp0 = spu_and(mask1, spu_cmpeq(sdata, 0));
+ nonzeroes = spu_cntlz(spu_gather(cmp0));
+ /*
+ * First element of nonzeroes - 15 is the number of leading non-zero
+ * bytes plus 1 for the zero byte.
+ */
+ if (checklen) {
+ vtmp = spu_add(curlen, 15);
+ vtmp2 = spu_cmpgt(nonzeroes, vtmp);
+ nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2);
+ }
+
+ vtmp = spu_cmpgt(nonzeroes, val31);
+ /*
+ * Note: using immediate (constant 31) vs a vector value (val31) does
+ * not give different results, and we have to have a vector val31 for
+ * the spu_sel below, so use val31 everywhere.
+ */
+ vtmp = spu_sel(nonzeroes, val31, vtmp);
+ /*
+ * So vtmp is now min(nonzeroes, 31), the number of bytes + 16 that we
+ * want to copy from the first 16 bytes of the source.
+ */
+ if (checklen) {
+ curlen = spu_sub(vtmp, curlen);
+ curlen = spu_sub(15, curlen);
+ }
+
+ /*
+ * We want a right shift 0xff with fill by ones of (vtmp - 15) bytes, but
+ * that doesn't exist so use spu_slqwbyte and vtmp all ones left by
+ * (31 - vtmp). Note: this can also use spu_rlqwbytebc with spu_rlqw.
+ */
+ shift = spu_extract(spu_sub(val31, vtmp), 0);
+ maskzero = spu_slqwbyte(all_ones, shift);
+ maskzero = spu_and(mask1, maskzero);
+ *vdest = spu_sel(*vdest, sdata, maskzero);
+
+ vtmp = spu_cmpgt(nonzeroes, val31);
+ if (checklen) {
+ vtmp2 = spu_cmpgt(curlen, 0);
+ vtmp = spu_and(vtmp, vtmp2);
+ }
+ if (spu_extract(vtmp, 0)) {
+ sdata1 = sdata2;
+ sdata2 = *vsrc++;
+ sdata = spu_shuffle(sdata1, sdata2, shuffle);
+ cmp0 = spu_cmpeq(sdata, 0);
+ gathered_cmp = spu_gather(cmp0);
+ /*
+ * Copy 16 bytes at a time.
+ */
+ while ((spu_extract(gathered_cmp, 0) == 0) &&
+ (!checklen || (spu_extract(curlen, 0) > 15))) {
+ if (checklen)
+ curlen = spu_add(curlen, -16);
+ *++vdest = sdata;
+ sdata1 = sdata2;
+ sdata2 = *vsrc++;
+ sdata = spu_shuffle(sdata1, sdata2, shuffle);
+ cmp0 = spu_cmpeq(sdata, 0);
+ gathered_cmp = spu_gather(cmp0);
+ }
+ /*
+ * Copy 0 to 15 trailing bytes, either up to the smaller of curlen or
+ * the number of non-zero bytes.
+ */
+ nonzeroes = spu_cntlz(gathered_cmp);
+ if (checklen) {
+ vtmp = spu_add(curlen, 15);
+ vtmp2 = spu_cmpgt(nonzeroes, vtmp);
+ nonzeroes = spu_sel(nonzeroes, vtmp, vtmp2);
+ curlen = spu_sub(nonzeroes, curlen);
+ curlen = spu_sub(15, curlen);
+ }
+ shift = spu_extract(spu_sub(val31, nonzeroes), 0);
+ maskzero = spu_slqwbyte(all_ones, shift);
+ ++vdest;
+ *vdest = spu_sel(*vdest, sdata, maskzero);
+ }
+
+ if (checklen && lastzero) {
+ /*
+ * For strncat.
+ */
+ dest[maxlen - spu_extract(curlen, 0)] = '\0';
+ }
+ return (dest);
+}
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