[16/17] powerpc: Add string-fza.h
Commit Message
From: Richard Henderson <rth@twiddle.net>
While ppc has the more important string functions in assembly,
there are still a few generic routines used.
Use the Power 6 CMPB insn for testing of zeros.
Checked on powerpc64le-linux-gnu.
---
sysdeps/powerpc/string-fza.h | 70 ++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)
create mode 100644 sysdeps/powerpc/string-fza.h
Comments
On 9/2/22 3:39 PM, Adhemerval Zanella via Libc-alpha wrote:
> From: Richard Henderson <rth@twiddle.net>
>
> While ppc has the more important string functions in assembly,
> there are still a few generic routines used.
>
> Use the Power 6 CMPB insn for testing of zeros.
>
> Checked on powerpc64le-linux-gnu.
> ---
> sysdeps/powerpc/string-fza.h | 70 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 70 insertions(+)
> create mode 100644 sysdeps/powerpc/string-fza.h
>
> diff --git a/sysdeps/powerpc/string-fza.h b/sysdeps/powerpc/string-fza.h
> new file mode 100644
> index 0000000000..5f7e9c5cbe
> --- /dev/null
> +++ b/sysdeps/powerpc/string-fza.h
> @@ -0,0 +1,70 @@
> +/* Zero byte detection; basics. PowerPC version.
> + Copyright (C) 2022 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 POWERPC_STRING_FZA_H
> +#define POWERPC_STRING_FZA_H 1
> +
> +/* PowerISA 2.03 (POWER6) provides cmpb instruction. */
Should this read "PowerISA 2.05"? cmpb is listed as implemented from
v2.05 in ISA 3.1.
> +#ifdef _ARCH_PWR6
> +# include <string-optype.h>
> +
> +/* This function returns 0xff for each byte that is
> + equal between X1 and X2. */
> +
> +static inline op_t
> +find_eq_all (op_t x1, op_t x2)
> +{
> + op_t ret;
> + asm ("cmpb %0,%1,%2" : "=r"(ret) : "r"(x1), "r"(x2));
Is it possible to use the gcc builtin __builtin_cmpb?
Otherwise, LGTM.
> + return ret;
> +}
> +
> +/* This function returns 0xff for each byte that is zero in X. */
> +
> +static inline op_t
> +find_zero_all (op_t x)
> +{
> + return find_eq_all (x, 0);
> +}
> +
> +/* Identify zero bytes in X1 or equality between X1 and X2. */
> +
> +static inline op_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 inline op_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 /* _ARCH_PWR6 */
> +
> +#endif /* STRING_FZA_H *
On 06/09/22 11:48, Paul E Murphy wrote:
>
>
> On 9/2/22 3:39 PM, Adhemerval Zanella via Libc-alpha wrote:
>> From: Richard Henderson <rth@twiddle.net>
>>
>> While ppc has the more important string functions in assembly,
>> there are still a few generic routines used.
>>
>> Use the Power 6 CMPB insn for testing of zeros.
>>
>> Checked on powerpc64le-linux-gnu.
>> ---
>> sysdeps/powerpc/string-fza.h | 70 ++++++++++++++++++++++++++++++++++++
>> 1 file changed, 70 insertions(+)
>> create mode 100644 sysdeps/powerpc/string-fza.h
>>
>> diff --git a/sysdeps/powerpc/string-fza.h b/sysdeps/powerpc/string-fza.h
>> new file mode 100644
>> index 0000000000..5f7e9c5cbe
>> --- /dev/null
>> +++ b/sysdeps/powerpc/string-fza.h
>> @@ -0,0 +1,70 @@
>> +/* Zero byte detection; basics. PowerPC version.
>> + Copyright (C) 2022 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 POWERPC_STRING_FZA_H
>> +#define POWERPC_STRING_FZA_H 1
>> +
>> +/* PowerISA 2.03 (POWER6) provides cmpb instruction. */
>
> Should this read "PowerISA 2.05"? cmpb is listed as implemented from v2.05 in ISA 3.1.
Yes, it should be 2.05 indeed.
>
>> +#ifdef _ARCH_PWR6
>> +# include <string-optype.h>
>> +
>> +/* This function returns 0xff for each byte that is
>> + equal between X1 and X2. */
>> +
>> +static inline op_t
>> +find_eq_all (op_t x1, op_t x2)
>> +{
>> + op_t ret;
>> + asm ("cmpb %0,%1,%2" : "=r"(ret) : "r"(x1), "r"(x2));
>
> Is it possible to use the gcc builtin __builtin_cmpb?
Unfortunately __builtin_cmpb is only supported on GCC 8+.
>
> Otherwise, LGTM.
>
new file mode 100644
@@ -0,0 +1,70 @@
+/* Zero byte detection; basics. PowerPC version.
+ Copyright (C) 2022 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 POWERPC_STRING_FZA_H
+#define POWERPC_STRING_FZA_H 1
+
+/* PowerISA 2.03 (POWER6) provides cmpb instruction. */
+#ifdef _ARCH_PWR6
+# include <string-optype.h>
+
+/* This function returns 0xff for each byte that is
+ equal between X1 and X2. */
+
+static inline op_t
+find_eq_all (op_t x1, op_t x2)
+{
+ op_t ret;
+ asm ("cmpb %0,%1,%2" : "=r"(ret) : "r"(x1), "r"(x2));
+ return ret;
+}
+
+/* This function returns 0xff for each byte that is zero in X. */
+
+static inline op_t
+find_zero_all (op_t x)
+{
+ return find_eq_all (x, 0);
+}
+
+/* Identify zero bytes in X1 or equality between X1 and X2. */
+
+static inline op_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 inline op_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 /* _ARCH_PWR6 */
+
+#endif /* STRING_FZA_H */