variable delay (in micro seconds) in Mikro C

i want to give a variable delay in micro seconds to my servo depending on the angle i need
my program is working with delay_us(const value) function
but i need a program where i can give input to the function as a variable like what is done in vdelay_ms
when i tried giving 0.6 or 1.5 ms values to the vdelay_ms function it gave erroneous results.

can someone please help me out?!? i'm using micKro C compiler software