compiler-rt/lib/builtins/subvsi3.c

   1 //===-- subvsi3.c - Implement __subvsi3 -----------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements __subvsi3 for the compiler_rt library.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "int_lib.h"
  14
  15 // Returns: a - b
  16
  17 // Effects: aborts if a - b overflows
  18
  19 COMPILER_RT_ABI si_int __subvsi3(si_int a, si_int b) {
  20   si_int s = (su_int)a - (su_int)b;
  21   if (b >= 0) {
  22     if (s > a)
  23       compilerrt_abort();
  24   } else {
  25     if (s <= a)
  26       compilerrt_abort();
  27   }
  28   return s;
  29 }