ape/libm: add back fmod, remove modf

We removed the wrong file. Put it back.
This commit is contained in:
Ori Bernstein 2021-01-23 20:03:07 -08:00
parent 988bdd05a3
commit f76e28cb71
3 changed files with 28 additions and 53 deletions

View file

@ -0,0 +1,27 @@
/* floating-point mod function without infinity or NaN checking */
#include <math.h>
double
fmod (double x, double y)
{
int sign = 0, yexp;
double r, yfr;
if (y == 0)
return 0;
if (y < 0)
y = -y;
yfr = frexp (y, &yexp);
if (x < 0) {
sign = 1;
r = -x;
} else
r = x;
while (r >= y) {
int rexp;
double rfr = frexp (r, &rexp);
r -= ldexp (y, rexp - yexp - (rfr < yfr));
}
if (sign)
r = -r;
return r;
}

View file

@ -10,6 +10,7 @@ OFILES=\
fabs.$O\ fabs.$O\
floor.$O\ floor.$O\
fmin.$O\ fmin.$O\
fmod.$O\
gamma.$O\ gamma.$O\
hypot.$O\ hypot.$O\
j0.$O\ j0.$O\

View file

@ -1,53 +0,0 @@
#include <math.h>
#include <errno.h>
/* modf suitable for IEEE double-precision */
#define MASK 0x7ffL
#define SIGN 0x80000000
#define SHIFT 20
#define BIAS 1022L
typedef union
{
double d;
struct
{
long ms;
long ls;
} i;
} Cheat;
double
modf(double d, double *ip)
{
Cheat x;
int e;
if(-1 < d && d < 1) {
*ip = 0;
return d;
}
x.d = d;
x.i.ms &= ~SIGN;
e = (x.i.ms >> SHIFT) & MASK;
if(e == MASK || e == 0){
errno = EDOM;
*ip = (d > 0)? HUGE_VAL : -HUGE_VAL;
return 0;
}
e -= BIAS;
if(e <= SHIFT+1) {
x.i.ms &= ~(0x1fffffL >> e);
x.i.ls = 0;
} else
if(e <= SHIFT+33)
x.i.ls &= ~(0x7fffffffL >> (e-SHIFT-2));
if(d > 0){
*ip = x.d;
return d - x.d;
}else{
*ip = -x.d;
return d + x.d;
}
}