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https://github.com/Relintai/sdl2_frt.git
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24c86b5501
since the window system doesn't do it for us like other platforms. This prevents sticky keys and missed keys when going in and out of focus, for example Alt would appear to stick if switching away from an SDL app with Alt-Tab and had to be pressed again. CR: Sam
80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
/* @(#)s_scalbn.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#if defined(LIBM_SCCS) && !defined(lint)
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static const char rcsid[] =
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"$NetBSD: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
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#endif
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/*
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* scalbn (double x, int n)
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* scalbn(x,n) returns x* 2**n computed by exponent
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* manipulation rather than by actually performing an
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* exponentiation or a multiplication.
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*/
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#include "math_libm.h"
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#include "math_private.h"
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libm_hidden_proto(copysign)
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#ifdef __STDC__
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static const double
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#else
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static double
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#endif
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two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
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twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
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huge_val = 1.0e+300, tiny = 1.0e-300;
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libm_hidden_proto(scalbn)
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#ifdef __STDC__
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double scalbn(double x, int n)
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#else
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double scalbn(x, n)
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double x;
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int n;
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#endif
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{
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int32_t k, hx, lx;
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EXTRACT_WORDS(hx, lx, x);
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k = (hx & 0x7ff00000) >> 20; /* extract exponent */
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if (k == 0) { /* 0 or subnormal x */
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if ((lx | (hx & 0x7fffffff)) == 0)
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return x; /* +-0 */
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x *= two54;
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GET_HIGH_WORD(hx, x);
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k = ((hx & 0x7ff00000) >> 20) - 54;
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if (n < -50000)
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return tiny * x; /* underflow */
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}
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if (k == 0x7ff)
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return x + x; /* NaN or Inf */
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k = k + n;
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if (k > 0x7fe)
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return huge_val * copysign(huge_val, x); /* overflow */
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if (k > 0) { /* normal result */
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SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
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return x;
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}
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if (k <= -54) {
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if (n > 50000) /* in case integer overflow in n+k */
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return huge_val * copysign(huge_val, x); /* overflow */
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else
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return tiny * copysign(tiny, x); /* underflow */
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}
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k += 54; /* subnormal result */
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SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
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return x * twom54;
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}
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libm_hidden_def(scalbn)
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