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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2023-09-29 19:16:26 +0200 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2023-11-21 13:25:37 +0100 |
commit | 42c9cdf35f6aa27f41d20b9b170d6e4e83a76913 (patch) | |
tree | e31b61a39959d2cf2a201bbd7318e4fb7003ce9d /cpukit/compiler-rt/lib/builtins/clzdi2.c | |
parent | 31043fa6acdd31a41cf04f8f67f433c784b6000e (diff) |
compiler-rt/lib/builtins: Newqual-98
Diffstat (limited to 'cpukit/compiler-rt/lib/builtins/clzdi2.c')
-rw-r--r-- | cpukit/compiler-rt/lib/builtins/clzdi2.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/cpukit/compiler-rt/lib/builtins/clzdi2.c b/cpukit/compiler-rt/lib/builtins/clzdi2.c new file mode 100644 index 0000000000..12c17982a5 --- /dev/null +++ b/cpukit/compiler-rt/lib/builtins/clzdi2.c @@ -0,0 +1,35 @@ +//===-- clzdi2.c - Implement __clzdi2 -------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements __clzdi2 for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#include "int_lib.h" + +// Returns: the number of leading 0-bits + +#if !defined(__clang__) && \ + ((defined(__sparc__) && defined(__arch64__)) || defined(__mips64) || \ + (defined(__riscv) && __SIZEOF_POINTER__ >= 8)) +// On 64-bit architectures with neither a native clz instruction nor a native +// ctz instruction, gcc resolves __builtin_clz to __clzdi2 rather than +// __clzsi2, leading to infinite recursion. +#define __builtin_clz(a) __clzsi2(a) +extern int __clzsi2(si_int); +#endif + +// Precondition: a != 0 + +COMPILER_RT_ABI int __clzdi2(di_int a) { + dwords x; + x.all = a; + const si_int f = -(x.s.high == 0); + return clzsi((x.s.high & ~f) | (x.s.low & f)) + + (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); +} |