xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/subvdi3.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 //===-- subvdi3.c - Implement __subvdi3 -----------------------------------===//
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 __subvdi3 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 di_int __subvdi3(di_int a, di_int b) {
20   di_int s = (du_int)a - (du_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 }
30