program f90_TIME
    implicit none
    real(4)::t1,t2,ttmax

    write(6,*) 'system_clock'
    t1=DIFT(ttmax)
    call work()
    t2=DIFT(ttmax)
    write(6,*) t1,ttmax
    write(6,*) t2,ttmax
    write(6,*) 'time=',t2-t1

    write(6,*) 'cpu_time'
    call cpu_time(t1)
    call work()
    call cpu_time(t2)
    write(6,*) t1
    write(6,*) t2
    write(6,*) 'time=',t2-t1



stop

contains

    real(4) function DIFT(ttmax)
        real(4),intent(out)::ttmax
        integer::count,count_rate,count_max
        call system_clock(count,count_rate,count_max)
        ttmax=real(count_max)/real(count_rate)
        DIFT=real(count)/real(count_rate)
    end function DIFT


    subroutine WORK()
        integer::i
        real(8)::s

        s=1.0D0
        do i=1,20000000
           s=s*sin(s)+cos(s)
        end do

    end subroutine WORK

end program f90_TIME