MSP430FR2355: register won't update with value???

#include <msp430.h>
#include "stdlib.h"
#include "string.h"
#include "stdio.h"

    float f, b;
    int d;
    struct confComm
    {
        char clkFrq[9];
        char baudRate[6];
    };

void main()
{
    struct confComm const s = {"16000000", "115200"};
    f = (float)atol(s.clkFrq);
    b = (float)atol(s.baudRate);
    d = (int)(((f/b/16) - (int)(f/b/16)) * 16);
    UCA0CTLW0 = UCSWRST;
    UCA0BRW = (int)(f/b/16);
    UCA0MCTLW = d;
    UCA0CTLW0 &= ~UCSWRST;
}

Can someone please explain to me why UCA0MCTLW will NOT update to the value d?  if I look at the expression for d it is correct.

Thanks