compiler-rt/lib/subvsi3.c

//===-- subvsi3.c - Implement __subvsi3 -----------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __subvsi3 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//

#include "int_lib.h"
#include <stdlib.h>

// Returns: a - b

// Effects: aborts if a - b overflows

si_int
__subvsi3(si_int a, si_int b)
{
    si_int s = a - b;
    if (b >= 0)
    {
        if (s > a)
            abort();
    }
    else
    {
        if (s <= a)
            abort();
    }
    return s;
}