floor(3m) — RISC
Name
floor, ffloor, fabs, ceil, ceil, trunc, ftrunc, fmod, rint − floor, absolute value, ceiling, truncation, floating point remainder and round-to-nearest functions
Syntax
#include <math.h>
double floor(x)
double x;
float ffloor(x)
float x;
double ceil(x)
double x;
float fceil(x)
float x;
double trunc(x)
double x;
float ftrunc(x)
float x;
double fabs(x)
double x;
double fmod (x, y)
double x, y;
double rint(x)
double x;
Description
The floor and ffloor routines return the largest integer which is not greater than x for double and float data types, respectively.
The ceil and fceil routines return the smallest integer which is not less than x for double and float data types, respectively.
The trunc and ftrunc routines return the integer (represented as a floating-point number) of x with the fractional bits truncated for double and float data types respectively.
The fabs routine returns the absolute value |x|.
The fmod routine returns the floating point remainder of the division of x by y: zero if y is zero or if x/y would overflow; otherwise the number f with the same sign as x, such that x = iy + f for some integer i, and |f| < |y|.
The rint routine returns the integer (represented as a double precision number) nearest x in the direction of the prevailing rounding mode.
In the default rounding mode, to nearest, rint(x) is the integer nearest x with the additional stipulation that if |rint(x)−x|=1/2 then rint(x) is even. Other rounding modes can make rint act like floor or ceil, or round towards zero.
Another way to obtain an integer near x is to declare (in C)
double x; int k; k = x;
The C compiler rounds x towards 0 to get the integer k. Also note that, if x is larger than k can accommodate, the value of k and the presence or absence of an integer overflow are hard to predict.
The fabs routine is in libc.a rather than libm.a.