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Diffstat (limited to 'lib/lshrti3.c')
-rw-r--r-- | lib/lshrti3.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/lshrti3.c b/lib/lshrti3.c new file mode 100644 index 000000000..99258cee1 --- /dev/null +++ b/lib/lshrti3.c @@ -0,0 +1,44 @@ +//===-- lshrti3.c - Implement __lshrti3 -----------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements __lshrti3 for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#if __x86_64 + +#include "int_lib.h" + +// Returns: logical a >> b + +// Precondition: 0 <= b < bits_in_tword + +ti_int +__lshrti3(ti_int a, si_int b) +{ + const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT); + utwords input; + utwords result; + input.all = a; + if (b & bits_in_dword) // bits_in_dword <= b < bits_in_tword + { + result.high = 0; + result.low = input.high >> (b - bits_in_dword); + } + else // 0 <= b < bits_in_dword + { + if (b == 0) + return a; + result.high = input.high >> b; + result.low = (input.high << (bits_in_dword - b)) | (input.low >> b); + } + return result.all; +} + +#endif |