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https://github.com/libretro/RetroArch
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101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/*
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The MIT License (MIT)
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Copyright (c) 2015 Lachlan Tychsen-Smith (lachlan.ts@gmail.com)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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/*
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Assumes the floating point value |x / y| < 2,147,483,648
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*/
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#include "math_neon.h"
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float fmodf_c(float x, float y)
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{
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int n;
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union {
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float f;
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int i;
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} yinv;
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float a;
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//fast reciporical approximation (4x Newton)
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yinv.f = y;
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n = 0x3F800000 - (yinv.i & 0x7F800000);
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yinv.i = yinv.i + n;
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yinv.f = 1.41176471f - 0.47058824f * yinv.f;
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yinv.i = yinv.i + n;
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a = 2.0 - yinv.f * y;
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yinv.f = yinv.f * a;
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a = 2.0 - yinv.f * y;
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yinv.f = yinv.f * a;
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a = 2.0 - yinv.f * y;
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yinv.f = yinv.f * a;
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a = 2.0 - yinv.f * y;
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yinv.f = yinv.f * a;
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n = (int)(x * yinv.f);
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x = x - ((float)n) * y;
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return x;
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}
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float fmodf_neon_hfp(float x, float y)
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{
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#ifdef __MATH_NEON
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asm volatile (
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"vdup.f32 d1, d0[1] \n\t" //d1[0] = y
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"vdup.f32 d0, d0[0] \n\t" //d1[0] = y
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//fast reciporical approximation
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"vrecpe.f32 d2, d1 \n\t" //d2 = ~1.0 / d1
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"vrecps.f32 d3, d2, d1 \n\t" //d3 = 2.0 - d2 * d1;
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"vmul.f32 d2, d2, d3 \n\t" //d2 = d2 * d3;
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"vrecps.f32 d3, d2, d1 \n\t" //d3 = 2.0 - d2 * d1;
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"vmul.f32 d2, d2, d3 \n\t" //d2 = d2 * d3;
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"vrecps.f32 d3, d2, d1 \n\t" //d3 = 2.0 - d2 * d1;
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"vmul.f32 d2, d2, d3 \n\t" //d2 = d2 * d3;
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"vrecps.f32 d3, d2, d1 \n\t" //d3 = 2.0 - d2 * d1;
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"vmul.f32 d2, d2, d3 \n\t" //d2 = d2 * d3;
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"vmul.f32 d2, d2, d0 \n\t" //d2 = d2 * d0;
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"vcvt.s32.f32 d2, d2 \n\t" //d2 = (int) d2;
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"vcvt.f32.s32 d2, d2 \n\t" //d2 = (float) d2;
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"vmls.f32 d0, d1, d2 \n\t" //d0 = d0 - d1 * d2;
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::: "d0", "d1", "d2", "d3"
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);
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#endif
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}
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float fmodf_neon_sfp(float x, float y)
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{
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#ifdef __MATH_NEON
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asm volatile ("vmov.f32 s0, r0 \n\t");
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asm volatile ("vmov.f32 s1, r1 \n\t");
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fmodf_neon_hfp(x, y);
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asm volatile ("vmov.f32 r0, s0 \n\t");
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#else
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return fmodf_c(x,y);
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#endif
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};
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