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1 /* go-cdiv.c -- complex division routines
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2
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3 Copyright 2013 The Go Authors. All rights reserved.
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4 Use of this source code is governed by a BSD-style
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5 license that can be found in the LICENSE file. */
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6
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7 #include <complex.h>
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8 #include <math.h>
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9
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10 /* Calls to these functions are generated by the Go frontend for
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11 division of complex64 or complex128. We use these because Go's
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12 complex division expects slightly different results from the GCC
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13 default. When dividing NaN+1.0i / 0+0i, Go expects NaN+NaNi but
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14 GCC generates NaN+Infi. NaN+Infi seems wrong seems the rules of
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15 C99 Annex G specify that if either side of a complex number is Inf,
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16 the the whole number is Inf, but an operation involving NaN ought
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17 to result in NaN, not Inf. */
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18
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19 complex float
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20 __go_complex64_div (complex float a, complex float b)
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21 {
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22 if (__builtin_expect (b == 0, 0))
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23 {
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24 if (!isinf (crealf (a))
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25 && !isinf (cimagf (a))
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26 && (isnan (crealf (a)) || isnan (cimagf (a))))
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27 {
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28 /* Pass "1" to nanf to match math/bits.go. */
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29 return nanf("1") + nanf("1")*I;
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30 }
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31 }
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32 return a / b;
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33 }
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34
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35 complex double
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36 __go_complex128_div (complex double a, complex double b)
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37 {
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38 if (__builtin_expect (b == 0, 0))
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39 {
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40 if (!isinf (creal (a))
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41 && !isinf (cimag (a))
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42 && (isnan (creal (a)) || isnan (cimag (a))))
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43 {
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44 /* Pass "1" to nan to match math/bits.go. */
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45 return nan("1") + nan("1")*I;
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46 }
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47 }
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48 return a / b;
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49 }
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