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# define TGSOURCE "atan2.c"
#include <errno.h>
#include <math.h>
#include "_safety.h"
#include "_tgmath.h"
/** arc tangent **/
TYPE TGFN(atan2)(TYPE y, TYPE x)
{
SIGNAL_SAFE(0);
int classy = fpclassify(y);
int classx = fpclassify(x);
if (classy == FP_ZERO && classx == 0) {
if (signbit(x)) {
return copysign(M_PI, y);
} else {
return y;
}
}
if (classy == FP_ZERO) {
if (x < 0) {
return copysign(M_PI, y);
} else if (x > 0) {
return y;
}
}
if (classx == FP_ZERO) {
if (y < 0) {
return - M_PI_2;
} else if (y > 0) {
return M_PI_2;
}
}
if (classx == FP_INFINITE) {
if (classy == FP_INFINITE) {
if (signbit(x)) {
return copysign(3.0 * M_PI / 4.0, y);
} else {
return copysign(M_PI / 4.0, y);
}
} else if (y > 0) {
if (signbit(x)) {
return copysign(M_PI, y);
} else {
return copysign(0.0, y);
}
}
}
if (classy == FP_INFINITE && classx != FP_INFINITE) {
return copysign(M_PI_2, y);
}
if (y == 0 && x == 0) {
errno = EDOM; /* ARGUMENT(y) and ARGUMENT(x) are both LITERAL(0)) */
return TGHUGE;
}
if (0) {
errno = ERANGE; /* The result cannot be represented */
/* RETURN_FAILURE(CONSTANT(HUGE_VAL), A range error occurred); */
return TGHUGE;
}
TYPE ret = TGFN(tan)(y / x);
/* FIXME: quadrant */
/* RETURN_SUCCESS(a value in range `[-PI(), +PI()]'); */
return ret;
}
/***
functions compute the principal value of the arc tangent of
ARGUMENT(y)/ARGUMENT(x), using the signs of both to place the return value in
the correct quadrant.
***/
/*
IMPLEMENTATION(The value returned on a domain error, CONSTANT(HUGE_VAL))
LINK(m)
STDC(1)
*/
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