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math_vec2.c
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math_vec2.c
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/*
The MIT License (MIT)
Copyright (c) 2015 Lachlan Tychsen-Smith ([email protected])
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include "math_neon.h"
//vec2 scalar product
float
dot2_c(float v0[2], float v1[2])
{
float r;
r = v0[0]*v1[0];
r += v0[1]*v1[1];
return r;
}
void
normalize2_c(float v[2], float d[2])
{
float b, c, x;
union {
float f;
int i;
} a;
x = v[0]*v[0];
x += v[1]*v[1];
//fast invsqrt approx
a.f = x;
a.i = 0x5F3759DF - (a.i >> 1); //VRSQRTE
c = x * a.f;
b = (3.0f - c * a.f) * 0.5; //VRSQRTS
a.f = a.f * b;
c = x * a.f;
b = (3.0f - c * a.f) * 0.5;
a.f = a.f * b;
d[0] = v[0]*a.f;
d[1] = v[1]*a.f;
}
float
dot2_neon_hfp(float v0[2], float v1[2])
{
#ifdef __MATH_NEON
asm volatile (
"vld1.32 {d2}, [%0] \n\t" //d2={x0,y0}
"vld1.32 {d4}, [%1] \n\t" //d4={x1,y1}
"vmul.f32 d0, d2, d4 \n\t" //d0 = d2*d4
"vpadd.f32 d0, d0, d0 \n\t" //d0 = d[0] + d[1]
:: "r"(v0), "r"(v1)
:
);
#endif
}
float
dot2_neon_sfp(float v0[2], float v1[2])
{
#ifdef __MATH_NEON
dot2_neon_hfp(v0, v1);
asm volatile ("vmov.f32 r0, s0 \n\t");
#else
return dot2_c(v0, v1);
#endif
};
void
normalize2_neon(float v[2], float d[2])
{
#ifdef __MATH_NEON
asm volatile (
"vld1.32 d4, [%0] \n\t" //d4 = {x0,y0}
"vmul.f32 d0, d4, d4 \n\t" //d0 = d2*d2
"vpadd.f32 d0, d0 \n\t" //d0 = d[0] + d[1]
"vmov.f32 d1, d0 \n\t" //d1 = d0
"vrsqrte.f32 d0, d0 \n\t" //d0 = ~ 1.0 / sqrt(d0)
"vmul.f32 d2, d0, d1 \n\t" //d2 = d0 * d1
"vrsqrts.f32 d3, d2, d0 \n\t" //d3 = (3 - d0 * d2) / 2
"vmul.f32 d0, d0, d3 \n\t" //d0 = d0 * d3
"vmul.f32 d2, d0, d1 \n\t" //d2 = d0 * d1
"vrsqrts.f32 d3, d2, d0 \n\t" //d3 = (3 - d0 * d2) / 2
"vmul.f32 d0, d0, d3 \n\t" //d0 = d0 * d3
"vmul.f32 d4, d4, d0[0] \n\t" //d4 = d4*d0[0]
"vst1.32 d4, [%1] \n\t" //
:: "r"(v), "r"(d)
: "d0", "d1", "d2", "d3", "d4", "memory"
);
#else
normalize2_c(v, d);
#endif
}