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gbeauche |
1.1 |
/* |
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* fpu/mathlib.cpp - Floating-point math support library |
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* |
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* Basilisk II (C) 1997-2001 Christian Bauer |
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* |
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* MC68881/68040 fpu emulation |
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* |
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* Original UAE FPU, copyright 1996 Herman ten Brugge |
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* Rewrite for x86, copyright 1999-2001 Lauri Pesonen |
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* New framework, copyright 2000-2001 Gwenole Beauchesne |
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* Adapted for JIT compilation (c) Bernd Meyer, 2000-2001 |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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/* NOTE: this file shall be included only from fpu/fpu_*.cpp */ |
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#undef PRIVATE |
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#define PRIVATE static |
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#undef PUBLIC |
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#define PUBLIC /**/ |
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#undef FFPU |
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#define FFPU /**/ |
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#undef FPU |
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#define FPU fpu. |
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gbeauche |
1.2 |
#if defined(FPU_IEEE) && defined(USE_X87_ASSEMBLY) |
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gbeauche |
1.1 |
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PRIVATE fpu_extended fp_do_pow(fpu_extended x, fpu_extended y) |
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{ |
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fpu_extended value, exponent; |
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uae_s64 p = (uae_s64)y; |
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if (x == 0.0) { |
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if (y > 0.0) |
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return (y == (double) p && (p & 1) != 0 ? x : 0.0); |
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else if (y < 0.0) |
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return (y == (double) p && (-p & 1) != 0 ? 1.0 / x : 1.0 / fp_fabs (x)); |
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} |
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if (y == (double) p) { |
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fpu_extended r = 1.0; |
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if (p == 0) |
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return 1.0; |
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if (p < 0) { |
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p = -p; |
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x = 1.0 / x; |
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} |
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while (1) { |
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if (p & 1) |
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r *= x; |
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p >>= 1; |
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if (p == 0) |
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return r; |
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x *= x; |
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} |
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} |
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__asm__ __volatile__("fyl2x" : "=t" (value) : "0" (x), "u" (1.0) : "st(1)"); |
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__asm__ __volatile__("fmul %%st(1) # y * log2(x)\n\t" |
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"fst %%st(1)\n\t" |
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"frndint # int(y * log2(x))\n\t" |
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"fxch\n\t" |
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"fsub %%st(1) # fract(y * log2(x))\n\t" |
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"f2xm1 # 2^(fract(y * log2(x))) - 1\n\t" |
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: "=t" (value), "=u" (exponent) : "0" (y), "1" (value)); |
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value += 1.0; |
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__asm__ __volatile__("fscale" : "=t" (value) : "0" (value), "u" (exponent)); |
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return value; |
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} |
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PRIVATE fpu_extended fp_do_log1p(fpu_extended x) |
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{ |
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// TODO: handle NaN and +inf/-inf |
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fpu_extended value; |
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// The fyl2xp1 can only be used for values in |
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// -1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2 |
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// 0.29 is a safe value. |
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if (fp_fabs(x) <= 0.29) |
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__asm__ __volatile__("fldln2; fxch; fyl2xp1" : "=t" (value) : "0" (x)); |
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else |
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__asm__ __volatile__("fldln2; fxch; fyl2x" : "=t" (value) : "0" (x + 1.0)); |
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return value; |
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} |
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#endif |
