fixmul - Multiplies two fixed point values together. Allegro game programming
library.
#include <allegro.h>
fixed fixmul(fixed x, fixed y);
A fixed point value can be multiplied or divided by an integer with the normal
`*' and `/' operators. To multiply two fixed point values, though, you must
use this function.
If an overflow occurs, `errno' will be set and the maximum
possible value will be returned, but `errno' is not cleared if the operation
is successful. This means that if you are going to test for overflow you
should set `errno=0' before calling fixmul(). Example:
fixed result;
/* This will put 30000 into `result'. */
result = fixmul(itofix(10), itofix(3000));
/* But this overflows, and sets `errno'. */
result = fixmul(itofix(100), itofix(3000));
ASSERT(!errno);
Returns the clamped result of multiplying `x' by `y', setting `errno' to ERANGE
if there was an overflow.
fixadd(3), fixsub(3), fixdiv(3), ex3buf(3),
excustom(3), exfixed(3), exspline(3), exstars(3),
exupdate(3)