| 1 | //===-- Implementation of the tan function for x86_64 ---------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "src/math/tan.h" |
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| 10 | #include "src/__support/common.h" |
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| 11 | |
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| 12 | namespace LIBC_NAMESPACE { |
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| 13 | |
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| 14 | LLVM_LIBC_FUNCTION(double, tan, (double x)) { |
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| 15 | double result; |
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| 16 | // The fptan instruction pushes the number 1 on to the FP stack after |
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| 17 | // computing tan. So, we read out the one before popping the actual result. |
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| 18 | __asm__ __volatile__("fptan" : "+t" (x)); |
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| 19 | __asm__ __volatile__("fstpl %0" : "=m" (result)); |
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| 20 | return result; |
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| 21 | } |
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| 22 | |
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| 23 | } // namespace LIBC_NAMESPACE |
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| 24 | |
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