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Length: 688 (0x2b0)
Types: TextFile
Notes: UNIX file
Names: »log10.c«
└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
└─⟦f4b8d8c84⟧ UNIX V7 Filesystem
└─ ⟦this⟧ »libm/log10.c«
/*
* Evaluate the logarithm (base 10) function.
* (Hart 2355, 19.74)
*/
#include <math.h>
static double logntab[] ={
-0.1042911213725266949744122e+02,
0.1344458152275036223645300e+02,
-0.4185596001312662063300000e+01,
0.1828759212091999337000000e+00
};
static double logmtab[] ={
-0.1200695907020063424342180e+02,
0.1948096618798093652415500e+02,
-0.8911109060902708565400000e+01,
0.1000000000000000000000000e+01
};
double
log10(x)
double x;
{
double r, z;
int n;
if (x <= 0.0) {
errno = EDOM;
return (0.0);
}
x = frexp(x, &n);
x *= SQRT2;
z = (x-1.0)/(x+1.0);
r = z*z;
r = z*(_pol(r, logntab, 4)/_pol(r, logmtab, 4));
r += (n-0.5)*LOG2B10;
return (r);
}