[PATCH] remove unneeded len variable from SPU strlen code

[Jeff Johnston]

Patch applied.

-- Jeff J.

Patrick Mansfield wrote:
> Jeff -
>
> Can you please apply?
>
> Get rid of len variable in strlen code.
>
> This does not change the size or speed of the code for -O2 (it does for
> -O1), but makes the source a bit simpler to read.
>
> newlib/ChangeLog:
>
> 2008-02-11 Patrick Mansfield <patmans@us.ibm.com>
>
> 	* libc/machine/spu/strlen.c: Remove the len variable and unneeded
> 	  calculation of its value.
>
> Index: src/newlib/libc/machine/spu/strlen.c
> ===================================================================
> --- src.orig/newlib/libc/machine/spu/strlen.c
> +++ src/newlib/libc/machine/spu/strlen.c
> @@ -33,34 +33,36 @@
>  #include <spu_intrinsics.h>
>  #include <stddef.h>
>  
> -/* Calculates  the  length  of  the string s, not including the terminating
> +/*
> + * Calculates the length of the string s, not including the terminating
>   * \0 character.
>   */
>  size_t strlen(const char *s)
>  {
> -  size_t len;
>    unsigned int cnt, cmp, skip, mask;
>    vec_uchar16 *ptr, data;
>  
> -  /* Compensate for initial mis-aligned string.
> +  /*
> +   * Compensate for initial mis-aligned string.
>     */
> -  ptr = (vec_uchar16 *)s;
> +  ptr = (vec_uchar16 *)s; /* implicit 16 byte alignment when dereferenced */
>    skip = (unsigned int)(ptr) & 15;
>    mask = 0xFFFF >> skip;
>  
> -  data = *ptr++;
> +  data = *ptr;
>    cmp = spu_extract(spu_gather(spu_cmpeq(data, 0)), 0);
>    cmp &= mask;
>  
>    cnt = spu_extract(spu_cntlz(spu_promote(cmp, 0)), 0);
> -  len = cnt - (skip + 16);
>  
>    while (cnt == 32) {
> -    data = *ptr++;
> -    len -= 16;
> +    data = *++ptr;
>      cnt = spu_extract(spu_cntlz(spu_gather(spu_cmpeq(data, 0))), 0);
> -    len += cnt;
>    }
>  
> -  return (len);
> +  /*
> +   * The length is ptr aligned down to a 16 byte boundary, plus the offset
> +   * to the zero byte, minus the starting address s.
> +   */
> +  return ((((int) ptr & ~0xf) + (cnt - 16)) - (int) s);
>  }
>