llvm-project/compiler-rt/lib/builtins/lshrdi3.c

39 lines
1.2 KiB
C

//===-- lshrdi3.c - Implement __lshrdi3 -----------------------------------===//
//
// 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 __lshrdi3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// Returns: logical a >> b
// Precondition: 0 <= b < bits_in_dword
COMPILER_RT_ABI di_int __lshrdi3(di_int a, int b) {
const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
udwords input;
udwords result;
input.all = a;
if (b & bits_in_word) /* bits_in_word <= b < bits_in_dword */ {
result.s.high = 0;
result.s.low = input.s.high >> (b - bits_in_word);
} else /* 0 <= b < bits_in_word */ {
if (b == 0)
return a;
result.s.high = input.s.high >> b;
result.s.low = (input.s.high << (bits_in_word - b)) | (input.s.low >> b);
}
return result.all;
}
#if defined(__ARM_EABI__)
COMPILER_RT_ALIAS(__lshrdi3, __aeabi_llsr)
#endif