1 /* ===-- divdc3.c - Implement __divdc3 -------------------------------------===
3 * The LLVM Compiler Infrastructure
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
8 * ===----------------------------------------------------------------------===
10 * This file implements __divdc3 for the compiler_rt library.
12 * ===----------------------------------------------------------------------===
15 #define DOUBLE_PRECISION
20 /* Returns: the quotient of (a + ib) / (c + id) */
22 COMPILER_RT_ABI Dcomplex
23 __divdc3(double __a, double __b, double __c, double __d)
26 double __logbw = __compiler_rt_logb(crt_fmax(crt_fabs(__c), crt_fabs(__d)));
27 if (crt_isfinite(__logbw))
29 __ilogbw = (int)__logbw;
30 __c = crt_scalbn(__c, -__ilogbw);
31 __d = crt_scalbn(__d, -__ilogbw);
33 double __denom = __c * __c + __d * __d;
35 COMPLEX_REAL(z) = crt_scalbn((__a * __c + __b * __d) / __denom, -__ilogbw);
36 COMPLEX_IMAGINARY(z) = crt_scalbn((__b * __c - __a * __d) / __denom, -__ilogbw);
37 if (crt_isnan(COMPLEX_REAL(z)) && crt_isnan(COMPLEX_IMAGINARY(z)))
39 if ((__denom == 0.0) && (!crt_isnan(__a) || !crt_isnan(__b)))
41 COMPLEX_REAL(z) = crt_copysign(CRT_INFINITY, __c) * __a;
42 COMPLEX_IMAGINARY(z) = crt_copysign(CRT_INFINITY, __c) * __b;
44 else if ((crt_isinf(__a) || crt_isinf(__b)) &&
45 crt_isfinite(__c) && crt_isfinite(__d))
47 __a = crt_copysign(crt_isinf(__a) ? 1.0 : 0.0, __a);
48 __b = crt_copysign(crt_isinf(__b) ? 1.0 : 0.0, __b);
49 COMPLEX_REAL(z) = CRT_INFINITY * (__a * __c + __b * __d);
50 COMPLEX_IMAGINARY(z) = CRT_INFINITY * (__b * __c - __a * __d);
52 else if (crt_isinf(__logbw) && __logbw > 0.0 &&
53 crt_isfinite(__a) && crt_isfinite(__b))
55 __c = crt_copysign(crt_isinf(__c) ? 1.0 : 0.0, __c);
56 __d = crt_copysign(crt_isinf(__d) ? 1.0 : 0.0, __d);
57 COMPLEX_REAL(z) = 0.0 * (__a * __c + __b * __d);
58 COMPLEX_IMAGINARY(z) = 0.0 * (__b * __c - __a * __d);