[352] | 1 | /* origin: FreeBSD /usr/src/lib/msun/src/e_atan2l.c */
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| 2 | /*
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| 3 | * ====================================================
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| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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| 5 | *
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| 6 | * Developed at SunSoft, a Sun Microsystems, Inc. business.
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| 7 | * Permission to use, copy, modify, and distribute this
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| 8 | * software is freely granted, provided that this notice
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| 9 | * is preserved.
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| 10 | * ====================================================
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| 11 | *
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| 12 | */
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| 13 | /*
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| 14 | * See comments in atan2.c.
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| 15 | * Converted to long double by David Schultz <das@FreeBSD.ORG>.
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| 16 | */
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| 17 |
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| 18 | #include "libm.h"
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| 19 |
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| 20 | #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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| 21 | long double atan2l(long double y, long double x)
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| 22 | {
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| 23 | return atan2(y, x);
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| 24 | }
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| 25 | #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
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| 26 | #include "__invtrigl.h"
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| 27 |
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| 28 | long double atan2l(long double y, long double x)
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| 29 | {
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| 30 | union ldshape ux, uy;
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| 31 | long double z;
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| 32 | int m, ex, ey;
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| 33 |
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| 34 | if (isnan(x) || isnan(y))
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| 35 | return x+y;
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| 36 | if (x == 1)
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| 37 | return atanl(y);
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| 38 | ux.f = x;
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| 39 | uy.f = y;
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| 40 | ex = ux.i.se & 0x7fff;
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| 41 | ey = uy.i.se & 0x7fff;
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| 42 | m = 2*(ux.i.se>>15) | uy.i.se>>15;
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| 43 | if (y == 0) {
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| 44 | switch(m) {
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| 45 | case 0:
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| 46 | case 1: return y; /* atan(+-0,+anything)=+-0 */
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| 47 | case 2: return 2*pio2_hi; /* atan(+0,-anything) = pi */
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| 48 | case 3: return -2*pio2_hi; /* atan(-0,-anything) =-pi */
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| 49 | }
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| 50 | }
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| 51 | if (x == 0)
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| 52 | return m&1 ? -pio2_hi : pio2_hi;
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| 53 | if (ex == 0x7fff) {
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| 54 | if (ey == 0x7fff) {
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| 55 | switch(m) {
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| 56 | case 0: return pio2_hi/2; /* atan(+INF,+INF) */
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| 57 | case 1: return -pio2_hi/2; /* atan(-INF,+INF) */
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| 58 | case 2: return 1.5*pio2_hi; /* atan(+INF,-INF) */
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| 59 | case 3: return -1.5*pio2_hi; /* atan(-INF,-INF) */
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| 60 | }
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| 61 | } else {
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| 62 | switch(m) {
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| 63 | case 0: return 0.0; /* atan(+...,+INF) */
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| 64 | case 1: return -0.0; /* atan(-...,+INF) */
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| 65 | case 2: return 2*pio2_hi; /* atan(+...,-INF) */
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| 66 | case 3: return -2*pio2_hi; /* atan(-...,-INF) */
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| 67 | }
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| 68 | }
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| 69 | }
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| 70 | if (ex+120 < ey || ey == 0x7fff)
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| 71 | return m&1 ? -pio2_hi : pio2_hi;
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| 72 | /* z = atan(|y/x|) without spurious underflow */
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| 73 | if ((m&2) && ey+120 < ex) /* |y/x| < 0x1p-120, x<0 */
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| 74 | z = 0.0;
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| 75 | else
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| 76 | z = atanl(fabsl(y/x));
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| 77 | switch (m) {
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| 78 | case 0: return z; /* atan(+,+) */
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| 79 | case 1: return -z; /* atan(-,+) */
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| 80 | case 2: return 2*pio2_hi-(z-2*pio2_lo); /* atan(+,-) */
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| 81 | default: /* case 3 */
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| 82 | return (z-2*pio2_lo)-2*pio2_hi; /* atan(-,-) */
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| 83 | }
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| 84 | }
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| 85 | #endif
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