compiler-rt/lib/builtins/subvti3.c

   1 //===-- subvti3.c - Implement __subvti3 -----------------------------------===//
   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 __subvti3 for the compiler_rt library.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "int_lib.h"
  14
  15 #ifdef CRT_HAS_128BIT
  16
  17 // Returns: a - b
  18
  19 // Effects: aborts if a - b overflows
  20
  21 COMPILER_RT_ABI ti_int __subvti3(ti_int a, ti_int b) {
  22   ti_int s = (tu_int)a - (tu_int)b;
  23   if (b >= 0) {
  24     if (s > a)
  25       compilerrt_abort();
  26   } else {
  27     if (s <= a)
  28       compilerrt_abort();
  29   }
  30   return s;
  31 }
  32
  33 #endif // CRT_HAS_128BIT