1 //===-- Implementation of the tan function for x86_64 ---------------------===//
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 #include "src/math/tan.h"
10 #include "src/__support/common.h"
11 
12 namespace __llvm_libc {
13 
14 LLVM_LIBC_FUNCTION(double, tan, (double x)) {
15   double result;
16   double one;
17   // The fptan instruction pushes the number 1 on to the FP stack after
18   // computing tan. So, we read out the one before popping the actual result.
19   __asm__ __volatile__("fptan" : "=t"(one) : "f"(x));
20   __asm__ __volatile__("fstpl %0" : "=m"(result));
21   return result;
22 }
23 
24 } // namespace __llvm_libc
25