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* [glibc] riscv: Add string-fza.h and string-fzi.h
@ 2023-02-06 20:14 Adhemerval Zanella
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From: Adhemerval Zanella @ 2023-02-06 20:14 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=25788431c0f5264c4830415de0cdd4d9926cbad9
commit 25788431c0f5264c4830415de0cdd4d9926cbad9
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed Feb 1 12:44:17 2023 -0300
riscv: Add string-fza.h and string-fzi.h
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>
Diff:
---
sysdeps/riscv/string-fza.h | 69 +++++++++++++++++++++++++++++++++++++++++
sysdeps/riscv/string-fzi.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 146 insertions(+)
diff --git a/sysdeps/riscv/string-fza.h b/sysdeps/riscv/string-fza.h
new file mode 100644
index 0000000000..4429653a00
--- /dev/null
+++ b/sysdeps/riscv/string-fza.h
@@ -0,0 +1,69 @@
+/* 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
+#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..8f56c378ff
--- /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 */
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