llvm-project/compiler-rt/lib/modti3.c

36 lines
1.0 KiB
C

//===-- modti3.c - Implement __modti3 -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __modti3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#if __x86_64
#include "int_lib.h"
tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
// Returns: a % b
ti_int
__modti3(ti_int a, ti_int b)
{
const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
ti_int s = b >> bits_in_tword_m1; // s = b < 0 ? -1 : 0
b = (b ^ s) - s; // negate if s == -1
s = a >> bits_in_tword_m1; // s = a < 0 ? -1 : 0
a = (a ^ s) - s; // negate if s == -1
ti_int r;
__udivmodti4(a, b, (tu_int*)&r);
return (r ^ s) - s; // negate if s == -1
}
#endif