[PATCH 2/3] newlib: riscv: Optimize memchr() and memrchr()

[Kito Cheng]

> diff --git a/newlib/libc/machine/riscv/memchr.c b/newlib/libc/machine/riscv/memchr.c
> index 5c08c12813fe..4202c704e2f3 100644
> --- a/newlib/libc/machine/riscv/memchr.c
> +++ b/newlib/libc/machine/riscv/memchr.c
> @@ -29,10 +29,15 @@ QUICKREF
>         memchr ansi pure
>  */
>
> -#include <_ansi.h>
> -#include <string.h>
> -#include <limits.h>
> -#include "../../string/local.h"
> +#include <sys/asm.h>
> +#include <stddef.h>
> +#include "rv_string.h"
> +
> +#if __riscv_zilsd
> +#undef  SZREG
> +#define SZREG           8

Could you define a MOVE_UNIT rather than SZREG here? It's kinda confusing.

>
> -      src = (unsigned char *) asrc;
> +  if (src < end_addr)
> +    {
> +      uintxlen_t mask = __libc_splat_byte(d);
> +      uintlslen_t val;
> +
> +      do
> +        {
> +#if __riscv_zilsd
> +          asm volatile ("ld %0, 0(%1)"
> +                        : "=R" (val)
> +                        : "r" (src)
> +          );

I strongly prefer not to use inline asm here, let the compiler do
that, although I know upstream GCC doesn't implement that yet...

> diff --git a/newlib/libc/machine/riscv/memrchr.c b/newlib/libc/machine/riscv/memrchr.c
> index 8d15ccb780ec..a67c2fefe124 100644
> --- a/newlib/libc/machine/riscv/memrchr.c
> +++ b/newlib/libc/machine/riscv/memrchr.c
> @@ -29,61 +29,141 @@ QUICKREF
>         memrchr
>  */
>
> -#include <_ansi.h>
> -#include <string.h>
> -#include <limits.h>
> -#include "../../string/local.h"
> +#include <sys/asm.h>
> +#include <stddef.h>
> +#include "rv_string.h"
> +
> +#if __riscv_zilsd
> +#undef  SZREG
> +#define SZREG           8

Same here