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author | Richard Henderson <richard.henderson@linaro.org> | 2023-01-10 18:01:02 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-02-06 16:19:35 -0300 |
commit | c62b1c29c2100f6d0bb8fe6d5e35811bd8ab49d9 (patch) | |
tree | 0512bf2d4e936afdad81efd54c85a43260ce1073 /sysdeps/hppa/string-fzb.h | |
parent | be836d9153eb6c1203c6659befb38427514eb349 (diff) | |
download | glibc-c62b1c29c2100f6d0bb8fe6d5e35811bd8ab49d9.tar.gz glibc-c62b1c29c2100f6d0bb8fe6d5e35811bd8ab49d9.tar.xz glibc-c62b1c29c2100f6d0bb8fe6d5e35811bd8ab49d9.zip |
hppa: Add string-fza.h, string-fzc.h, and string-fzi.h
Use UXOR,SBZ to test for a zero byte within a word. While we can get semi-decent code out of asm-goto, we would do slightly better with a compiler builtin. For index_zero et al, sequential testing of bytes is less expensive than any tricks that involve a count-leading-zeros insn that we don't have. Checked on hppa-linux-gnu. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/hppa/string-fzb.h')
-rw-r--r-- | sysdeps/hppa/string-fzb.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/sysdeps/hppa/string-fzb.h b/sysdeps/hppa/string-fzb.h new file mode 100644 index 0000000000..d6b234a271 --- /dev/null +++ b/sysdeps/hppa/string-fzb.h @@ -0,0 +1,63 @@ +/* Zero byte detection, boolean. HPPA 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_FZB_H +#define _STRING_FZB_H 1 + +#include <sys/cdefs.h> +#include <string-optype.h> + +_Static_assert (sizeof (op_t) == 4, "64-bit not supported"); + +/* Determine if any byte within X is zero. This is a pure boolean test. */ +static __always_inline _Bool +has_zero (op_t x) +{ + /* It's more useful to expose a control transfer to the compiler + than to expose a proper boolean result. */ + asm goto ("uxor,sbz %%r0,%0,%%r0\n\t" + "b,n %l1" : : "r"(x) : : nbz); + return 1; + nbz: + return 0; +} + +/* Likewise, but for byte equality between X1 and X2. */ +static __always_inline _Bool +has_eq (op_t x1, op_t x2) +{ + asm goto ("uxor,sbz %0,%1,%%r0\n\t" + "b,n %l2" : : "r"(x1), "r"(x2) : : nbz); + return 1; + nbz: + return 0; +} + +/* Likewise, but for zeros in X1 and equal bytes between X1 and X2. */ +static __always_inline _Bool +has_zero_eq (op_t x1, op_t x2) +{ + asm goto ("uxor,sbz %%r0,%0,%%r0\n\t" + "uxor,nbz %0,%1,%%r0\n\t" + "b,n %l2" : : "r"(x1), "r"(x2) : : sbz); + return 0; + sbz: + return 1; +} + +#endif /* _STRING_FZB_H */ |