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

41 lines
1.1 KiB
C

//===-- ashldi3.c - Implement __ashldi3 -----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __ashldi3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// Returns: a << b
// Precondition: 0 <= b < bits_in_dword
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.low = 0;
result.high = input.low << (b - bits_in_word);
}
else // 0 <= b < bits_in_word
{
if (b == 0)
return a;
result.low = input.low << b;
result.high = (input.high << b) | (input.low >> (bits_in_word - b));
}
return result.all;
}