[PATCH] optimized SPU specific code for str[n]cpy and str[n]cat

[Patrick Mansfield <patmans at us dot ibm dot com>]

Jeff - can you please apply?

Optimized SPU specific code for str[n]cpy and str[n]cat.

These decrease (for simple performance tests) execution times compared to
current SPU code for these functions by 20 to 50 percent.

Generally, code size increases, with a worst case increase of 680 bytes.

newlib/ChangeLog:

2008-02-11 Patrick Mansfield <patmans@us.ibm.com>

	* libc/machine/spu/straddr.h: New file, supplies _straddr.
	* libc/machine/spu/strcat.c: Use _straddr and _strcpy.
	* libc/machine/spu/strcpy.c: Use _strcpy.
	* libc/machine/spu/strcpy.h: Supply _strcpy for optimized SPU
	  str[n]cpy and str[n]cat.
	* libc/machine/spu/strncat.c: Use _straddr and _strcpy.
	* libc/machine/spu/strncpy.c: Use _strcpy.

Index: quilt/newlib/libc/machine/spu/strcat.c
===================================================================
--- quilt.orig/newlib/libc/machine/spu/strcat.c
+++ quilt/newlib/libc/machine/spu/strcat.c
@@ -1,9 +1,6 @@
 /*
-  (C) Copyright 2001,2006,
+  (C) Copyright 2008
   International Business Machines Corporation,
-  Sony Computer Entertainment, Incorporated,
-  Toshiba Corporation,
-
   All rights reserved.
 
   Redistribution and use in source and binary forms, with or without
@@ -30,26 +27,19 @@
   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 <stddef.h>
 #include <string.h>
+#include "straddr.h"
+#include "strcpy.h"
 
-/* Appends the string pointed to by src (up to and including the /0
- * character) to the array pointed to by dest (overwriting the
+/*
+ * Appends the string pointed to by src (up to and including the /0
+ * character) to the array pointed to by dest overwriting the
  * /0 character at the end of dest. The strings may not overlap and
  * the dest string must have enough space for the result.
  */
-
 char *strcat(char * __restrict__ dest, const char * __restrict__ src)
 {
-  size_t d_len, s_len;
-
-  /* Determine the length of the src and dest input arrays.
-   */
-  d_len = strlen(dest);
-  s_len = strlen(src);
-
-  (void)memcpy((void *)(dest+d_len), (const void *)src, s_len + 1);
-
-  return ((char *)dest);
+  return _strncpy(_straddr(dest), src, 0, 0, 0);
 }
Index: quilt/newlib/libc/machine/spu/strcpy.h
===================================================================
--- /dev/null
+++ quilt/newlib/libc/machine/spu/strcpy.h
@@ -0,0 +1,180 @@
+/*
+  (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);
+}
Index: quilt/newlib/libc/machine/spu/strcpy.c
===================================================================
--- quilt.orig/newlib/libc/machine/spu/strcpy.c
+++ quilt/newlib/libc/machine/spu/strcpy.c
@@ -1,9 +1,6 @@
 /*
-  (C) Copyright 2001,2006,
+  (C) Copyright 2008
   International Business Machines Corporation,
-  Sony Computer Entertainment, Incorporated,
-  Toshiba Corporation,
-
   All rights reserved.
 
   Redistribution and use in source and binary forms, with or without
@@ -30,19 +27,15 @@
   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 <stddef.h>
+#include "strcpy.h"
 
-/* Copy the string pointed to by src (up to and including the /0
+/*
+ * Copy the string pointed to by src (up to and including the /0
  * character) into the array pointed to by dest. If copy between
  * two arrays that overlap, then behavior is undefined.
  */
-
 char * strcpy(char * __restrict__ dest, const char * __restrict__ src)
 {
-  /* Due to the need to support all alignment variances, this
-   * function can not easily be optimized. As a result, it is
-   * serviced using strlen and memcpy.
-   */
-  return ((char *)memcpy((void *)dest, (const void *)src, strlen(src)+1));
+  return _strncpy(dest, src, 0, 0, 0);
 }
Index: quilt/newlib/libc/machine/spu/strncat.c
===================================================================
--- quilt.orig/newlib/libc/machine/spu/strncat.c
+++ quilt/newlib/libc/machine/spu/strncat.c
@@ -1,9 +1,6 @@
 /*
-  (C) Copyright 2001,2006,
+  (C) Copyright 2008
   International Business Machines Corporation,
-  Sony Computer Entertainment, Incorporated,
-  Toshiba Corporation,
-
   All rights reserved.
 
   Redistribution and use in source and binary forms, with or without
@@ -30,68 +27,19 @@
   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 <stddef.h>
 #include <string.h>
+#include "straddr.h"
+#include "strcpy.h"
 
-/* Appends the string pointed to by src (up to and including the /0
+/*
+ * Appends the string pointed to by src (up to and including the /0
  * character) to the array pointed to by dest (overwriting the
  * /0 character at the end of dest. The strings may not overlap and
  * the dest string must have enough space for the result.
  */
-
-char * strncat(char * __restrict__ dest, const char * __restrict__ src, size_t n)
+char * strncat(char * __restrict__ dest, const char * __restrict__ src,
+               size_t n)
 {
-  unsigned int cmp, skip, mask, len;
-  vec_uchar16 *ptr, data;
-  vec_uint4 cnt, gt, N;
-  char *dst;
-
-  /* Determine the starting location to begin concatenation.
-   */
-  dst = dest + strlen(dest);
-
-  /* Copy the src image until either the src string terminates
-   * or n characters are copied.
-   */
-  N = spu_promote((unsigned int)n, 0);
-
-  /* Determine the string length, not including termination character,
-   * clamped to n characters.
-   */
-  ptr = (vec_uchar16 *)src;
-  skip = (unsigned int)(ptr) & 15;
-  mask = 0xFFFF >> skip;
-
-  data = *ptr++;
-  cmp = spu_extract(spu_gather(spu_cmpeq(data, 0)), 0);
-  cmp &= mask;
-
-  cnt = spu_cntlz(spu_promote(cmp, 0));
-  len = spu_extract(cnt, 0) - (skip + 16);
-
-  gt = spu_cmpgt(spu_promote(len, 0), N);
-
-  while (spu_extract(spu_andc(spu_cmpeq(cnt, 32), gt), 0)) {
-    data = *ptr++;
-    len -= 16;
-    cnt  = spu_cntlz(spu_gather(spu_cmpeq(data, 0)));
-    len += spu_extract(cnt, 0);
-
-    gt = spu_cmpgt(spu_promote(len, 0), N);
-  }
-
-  /* len = MIN(len, n)
-   */
-  len = spu_extract(spu_sel(spu_promote(len, 0), N, gt), 0);
-
-  /* Perform a memcpy of the resulting length
-   */
-  (void)memcpy((void *)dst, (const void *)src, len);
-
-  /* Terminate the resulting concetenated string.
-   */
-  dst[len] = '\0';
-
-  return (dest);
+  return _strncpy(_straddr(dest), src, n, 1, 1);
 }
Index: quilt/newlib/libc/machine/spu/strncpy.c
===================================================================
--- quilt.orig/newlib/libc/machine/spu/strncpy.c
+++ quilt/newlib/libc/machine/spu/strncpy.c
@@ -1,9 +1,6 @@
 /*
-  (C) Copyright 2001,2006,
+  (C) Copyright 2008
   International Business Machines Corporation,
-  Sony Computer Entertainment, Incorporated,
-  Toshiba Corporation,
-
   All rights reserved.
 
   Redistribution and use in source and binary forms, with or without
@@ -30,58 +27,16 @@
   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 <stddef.h>
 #include <string.h>
+#include "strcpy.h"
 
-/* Copy the string up to n character from memory area src to
- * memory area dest. The memory areas may not overlap. The
- * strncpy subroutine returns a pointer to dest.
+/*
+ * Copy the string up to n character from memory area src to memory area
+ * dest. The memory areas may not overlap. The strncpy subroutine returns
+ * a pointer to dest.
  */
 char * strncpy(char * __restrict__ dest, const char * __restrict__ src, size_t n)
 {
-  unsigned int len;
-  unsigned int cmp, skip, mask;
-  vec_uchar16 *ptr, data;
-  vec_uint4 cnt, gt, N;
-
-  N = spu_promote((unsigned int)n, 0);
-
-  /* Determine the string length, including termination character,
-   * clamped to n characters.
-   */
-  ptr = (vec_uchar16 *)src;
-  skip = (unsigned int)(ptr) & 15;
-  mask = 0xFFFF >> skip;
-
-  data = *ptr++;
-  cmp = spu_extract(spu_gather(spu_cmpeq(data, 0)), 0);
-  cmp &= mask;
-
-  cnt = spu_cntlz(spu_promote(cmp, 0));
-  len = spu_extract(cnt, 0) - (skip + 15);
-
-  gt = spu_cmpgt(spu_promote(len, 0), N);
-
-  while (spu_extract(spu_andc(spu_cmpeq(cnt, 32), gt), 0)) {
-    data = *ptr++;
-    len -= 16;
-    cnt  = spu_cntlz(spu_gather(spu_cmpeq(data, 0)));
-    len += spu_extract(cnt, 0);
-
-    gt = spu_cmpgt(spu_promote(len, 0), N);
-  }
-
-  /* len = MIN(len, n)
-   */
-  len = spu_extract(spu_sel(spu_promote((unsigned int)len, 0), N, gt), 0);
-
-  /* Padding
-   */
-  if (len != n) {
-    memset(dest + len, 0, n - len);
-  }
-  /* Perform a memcpy of the resulting length
-   */
-  return ((char *)memcpy((void *)dest, (const void *)src, len));
+  return _strncpy(dest, src, n, 1, 0);
 }
Index: quilt/newlib/libc/machine/spu/straddr.h
===================================================================
--- /dev/null
+++ quilt/newlib/libc/machine/spu/straddr.h
@@ -0,0 +1,75 @@
+/*
+  (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 the inline _straddr for use by strncpy and strncat.
+*
+* _straddr: search the string s, and return the address of the first byte
+* containing zero.
+*/
+static inline char *_straddr(const char *s)
+{
+  unsigned int cnt, cmp, skip, mask;
+  vec_uchar16 *ptr, data;
+
+  /*
+   * Compensate for unaligned strings.
+   */
+  ptr = (vec_uchar16 *)s; /* implicit (s & ~0xf) */
+  skip = (unsigned int)(ptr) & 0xf;
+  /*
+   * skip the first skip bytes starting at (s & ~0xf).
+   */
+  mask = 0xFFFF >> skip;
+
+  data = *ptr;
+  cmp = spu_extract(spu_gather(spu_cmpeq(data, 0)), 0);
+  cmp &= mask;
+
+  cnt = spu_extract(spu_cntlz(spu_promote(cmp, 0)), 0);
+
+  while (cnt == 32) {
+    data = *++ptr;
+    cnt = spu_extract(spu_cntlz(spu_gather(spu_cmpeq(data, 0))), 0);
+    /*
+     * The first 16 bits for gather on a byte vector are zero, so if cnt
+     * is 32, none of the 16 bytes in data was zero. And, there are (cnt -
+     * 16) non-zero bytes in data.
+     */
+  }
+  /*
+   * The first non-zero byte is at ptr aligned down plus the number of
+   * non-zero bytes seen.
+   */
+  return ((char*) (((int) ptr & ~0xf) + (cnt - 16)));
+}