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// These unions are necessary to put the constants in .rodata rather than .data.
//! @todo is it possible to remove them somehow?
typedef union {
/* 0x0 */ double d;
/* 0x0 */ struct {
/* 0x0 */ unsigned int hi;
/* 0x4 */ unsigned int lo;
} word;
} du;
typedef union {
/* 0x0 */ float f;
/* 0x0 */ unsigned int i;
} fu;
static const du P[5] = {
{ 1.0 }, { -0.16666659550427756 }, { 0.008333066246082155 }, { -1.980960290193795E-4 }, { 2.605780637968037E-6 }
};
static const du rpi = { 0.3183098861837907 };
static const du pihi = { 3.1415926218032837 };
static const du pilo = { 3.178650954705639E-8 };
static const fu zero = { 0.0 };
extern const fu NAN;
float sinf(float x) {
double dx; // double x
double xsq; // x squared
double poly;
double dn;
int n;
double result;
int ix; // int x
int xpt;
ix = *(int*) &x;
xpt = (ix >> 22) & 0x1FF;
if (xpt < 255) {
dx = x;
if (xpt >= 230) {
xsq = dx * dx;
poly = (((((P[4].d * xsq) + P[3].d) * xsq) + P[2].d) * xsq) + P[1].d;
result = ((dx * xsq) * poly) + dx;
return result;
} else {
return x;
}
}
if (xpt < 310) {
dx = x;
dn = dx * rpi.d;
if (dn >= 0) {
n = dn + 0.5;
} else {
n = dn - 0.5;
}
dn = n;
dx -= dn * pihi.d;
dx -= dn * pilo.d;
xsq = dx * dx;
poly = (((((P[4].d * xsq) + P[3].d) * xsq) + P[2].d) * xsq) + P[1].d;
result = ((dx * xsq) * poly) + dx;
if ((n & 0x1) == 0) {
return result;
} else {
return -(float) result;
}
}
if (x != x) {
return NAN.f;
}
return zero.f;
}
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