llvm-project/compiler-rt/lib/builtins/ashldi3.c

39 lines
1.2 KiB
C

// ====-- ashldi3.c - Implement __ashldi3 ---------------------------------===//
//
// 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 __ashldi3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// Returns: a << b
// Precondition: 0 <= b < bits_in_dword
COMPILER_RT_ABI di_int __ashldi3(di_int a, si_int b) {
const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
dwords input;
dwords result;
input.all = a;
if (b & bits_in_word) /* bits_in_word <= b < bits_in_dword */ {
result.s.low = 0;
result.s.high = input.s.low << (b - bits_in_word);
} else /* 0 <= b < bits_in_word */ {
if (b == 0)
return a;
result.s.low = input.s.low << b;
result.s.high = (input.s.high << b) | (input.s.low >> (bits_in_word - b));
}
return result.all;
}
#if defined(__ARM_EABI__)
COMPILER_RT_ALIAS(__ashldi3, __aeabi_llsl)
#endif