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#include "ultra64.h"
#include "z_math.h" // TODO: libultra should not have access to game-side headers
static const du P[] = {
{ 0x3FF00000, 0x00000000 }, { 0xBFC55554, 0xBC83656D }, { 0x3F8110ED, 0x3804C2A0 },
{ 0xBF29F6FF, 0xEEA56814 }, { 0x3EC5DBDF, 0x0E314BFE },
};
static const du rpi = { 0x3FD45F30, 0x6DC9C883 };
static const du pihi = { 0x400921FB, 0x50000000 };
static const du pilo = { 0x3E6110B4, 0x611A6263 };
static const fu zero = { 0x00000000 };
/**
* @param angle radians
* @return cos(angle)
*/
f32 cosf(f32 angle) {
f32 absx;
f64 dx;
f64 xSq;
f64 polyApprox;
f64 dn;
s32 n;
f64 result;
s32 ix = *(s32*)∠
s32 xpt = (ix >> 22);
xpt &= 0x1FF;
if (xpt < 0x136) {
absx = (angle > 0) ? angle : -angle;
dx = absx;
dn = dx * rpi.d + 0.5;
n = ROUND(dn);
dn = n;
dn -= 0.5;
dx -= dn * pihi.d;
dx -= dn * pilo.d;
xSq = SQ(dx);
polyApprox = ((P[4].d * xSq + P[3].d) * xSq + P[2].d) * xSq + P[1].d;
result = dx + (dx * xSq) * polyApprox;
if (!(n & 1)) {
return (f32)result;
}
return -(f32)result;
}
if (angle != angle) {
return __libm_qnan_f;
}
return zero.f;
}
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