dquakeplus/source/libpspmath/vfpu_atanf.c
2022-02-08 16:49:56 -05:00

57 lines
1.1 KiB
C

#include "pspmath.h"
float vfpu_atanf(float x) {
float result;
// result = asinf(x/sqrt(x*x+1))
__asm__ volatile (
"mtv %1, S000\n"
"vmul.s S001, S000, S000\n"
"vadd.s S001, S001, S001[1]\n"
"vrsq.s S001, S001\n"
"vmul.s S000, S000, S001\n"
"vasin.s S000, S000\n"
"vcst.s S001, VFPU_PI_2\n"
"vmul.s S000, S000, S001\n"
"mfv %0, S000\n"
: "=r"(result) : "r"(x));
return result;
}
#define PI 3.14159265358979f
#define PI_2 1.57079632679489f
inline static float fabsf(float x) {
float r;
__asm__ volatile( "abs.s %0, %1" : "=f"(r) :"f"(x):"memory");
return r;
}
/* double a;
if (fabs(x) >= fabs(y)) {
a = atan(y/x) ;
if (x < 0.0) {
if (y >= 0.0) a += _pi ;
else a -= _pi ;
}
}
else {
a = -atan(x/y) ;
if (y < 0.0) a -= _halfpi ;
else a += _halfpi ;
}
return a ;*/
float vfpu_atan2f(float y, float x) {
float r;
if (fabsf(x) >= fabsf(y)) {
r = vfpu_atanf(y/x);
if (x < 0.0f) r += (y>=0.0f ? PI : -PI);
} else {
r = -vfpu_atanf(x/y);
r += (y < 0.0f ? -PI_2 : PI_2);
}
return r;
}