[PATCH v12 21/31] riscv: Add string-fza.h and string-fzi.h

[Adhemerval Zanella Netto]

On 03/02/23 16:47, Noah Goldstein wrote:
> On Thu, Feb 2, 2023 at 12:12 PM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
>>
>> It uses the bitmanip extension to optimize index_fist and index_last
>> with clz/ctz (using generic implementation that routes to compiler
>> builtin) and orc.b to check null bytes.
>>
>> Checked the string test on riscv64 user mode.
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>  sysdeps/riscv/string-fza.h | 70 ++++++++++++++++++++++++++++++++++
>>  sysdeps/riscv/string-fzi.h | 77 ++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 147 insertions(+)
>>  create mode 100644 sysdeps/riscv/string-fza.h
>>  create mode 100644 sysdeps/riscv/string-fzi.h
>>
>> diff --git a/sysdeps/riscv/string-fza.h b/sysdeps/riscv/string-fza.h
>> new file mode 100644
>> index 0000000000..9c7a6efba2
>> --- /dev/null
>> +++ b/sysdeps/riscv/string-fza.h
>> @@ -0,0 +1,70 @@
>> +/* Zero byte detection; basics.  RISCV version.
>> +   Copyright (C) 2023 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _RISCV_STRING_FZA_H
>> +#define _RISCV_STRING_FZA_H 1
>> +
>> +#ifdef __riscv_zbb
>> +/* With bitmap extension we can use orc.b to find all zero bytes.  */
>> +# include <string-misc.h>
>> +# include <string-optype.h>
>> +
>> +/* The functions return a byte mask.  */
>> +typedef op_t find_t;
>> +
>> +/* This function returns 0xff for each byte that is zero in X.  */
>> +static __always_inline find_t
>> +find_zero_all (op_t x)
>> +{
>> +  find_t r;
>> +  asm ("orc.b %0, %1" : "=r" (r) : "r" (x));
>> +  return ~r;
>> +}
>> +
>> +/* This function returns 0xff for each byte that is equal between X1 and
>> +   X2.  */
>> +static __always_inline find_t
>> +find_eq_all (op_t x1, op_t x2)
>> +{
>> +  return find_zero_all (x1 ^ x2);
>> +}
>> +
>> +/* Identify zero bytes in X1 or equality between X1 and X2.  */
>> +static __always_inline find_t
>> +find_zero_eq_all (op_t x1, op_t x2)
>> +{
>> +  return find_zero_all (x1) | find_eq_all (x1, x2);
>> +}
>> +
>> +/* Identify zero bytes in X1 or inequality between X1 and X2.  */
>> +static __always_inline find_t
>> +find_zero_ne_all (op_t x1, op_t x2)
>> +{
>> +  return find_zero_all (x1) | ~find_eq_all (x1, x2);
>> +}
>> +
>> +/* Define the "inexact" versions in terms of the exact versions.  */
>> +# define find_zero_low         find_zero_all
>> +# define find_eq_low           find_eq_all
>> +# define find_zero_eq_low      find_zero_eq_all
>> +# define find_zero_ne_low      find_zero_ne_all
>> +#else
>> +#include <sysdeps/generic/string-fza.h>
>> +#endif
>> +
>> +#endif /* _RISCV_STRING_FZA_H  */
>> diff --git a/sysdeps/riscv/string-fzi.h b/sysdeps/riscv/string-fzi.h
>> new file mode 100644
>> index 0000000000..3cde113afb
>> --- /dev/null
>> +++ b/sysdeps/riscv/string-fzi.h
>> @@ -0,0 +1,77 @@
>> +/* Zero byte detection; indexes.  RISCV version.
>> +   Copyright (C) 2023 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _STRING_RISCV_FZI_H
>> +#define _STRING_RISCV_FZI_H 1
>> +
>> +#ifdef __riscv_zbb
>> +# include <sysdeps/generic/string-fzi.h>
>> +#else
>> +/* Without bitmap clz/ctz extensions, it is faster to direct test the bits
>> +   instead of calling compiler auxiliary functions.  */
>> +# include <string-optype.h>
>> +
>> +static __always_inline unsigned int
>> +index_first (find_t c)
>> +{
>> +  if (c & 0x80U)
>> +    return 0;
>> +  if (c & 0x8000U)
>> +    return 1;
>> +  if (c & 0x800000U)
>> +    return 2;
>> +
>> +  if (sizeof (op_t) == 4)
>> +    return 3;
>> +
>> +  if (c & 0x80000000U)
>> +    return 3;
>> +  if (c & 0x8000000000UL)
>> +    return 4;
>> +  if (c & 0x800000000000UL)
>> +    return 5;
>> +  if (c & 0x80000000000000UL)
>> +    return 6;
>> +  return 7;
>> +}
>> +
>> +static __always_inline unsigned int
>> +index_last (find_t c)
>> +{
>> +  if (sizeof (op_t) == 8)
>> +    {
>> +      if (c & 0x8000000000000000UL)
>> +       return 7;
>> +      if (c & 0x80000000000000UL)
>> +       return 6;
>> +      if (c & 0x800000000000UL)
>> +       return 5;
>> +      if (c & 0x8000000000UL)
>> +       return 4;
>> +    }
>> +  if (c & 0x80000000U)
>> +    return 3;
>> +  if (c & 0x800000U)
>> +    return 2;
>> +  if (c & 0x8000U)
>> +    return 1;
>> +  return 0;
>> +}
>> +#endif
>> +
>> +#endif /* STRING_FZI_H */
>> --
>> 2.34.1
>>
> 
> Has WS error:
> ```
> Applying: riscv: Add string-fza.h and string-fzi.h
> .git/rebase-apply/patch:115: trailing whitespace.
>    instead of calling compiler auxiliary functions.  */
> warning: 1 line adds whitespace errors.
> ```

Thanks, I will fix it before apply.