C51 compiler type cast issues...

I am using Keil, C51 Compiler with Infineon XC886 8-bit micro....

I have a simple application that acquires rising and falling edges at P3.0 and then calculates the Period and Pulse Width in ticks of T12.

Then the program "based on these values" stretches the pulse using a 2D lookup table and generates a PWM output on P3.7 (it is inverted).

The lookup table returns a value from 0 to 1000.... a value of 300 means add 30% to the actual pulse width (NOT duty cycle which is %).

Everything seems to work except the output pulse width is incorrect.

I have (by process of elimintation) worked out the portion of code that is causing problems, but I think that it is actually the compiler.

The name of the function is "modifyDutyCycle"..

Step 1:
First I disabled all interrupts then cut and paste the contents of the function into main.
Since the calculation was quite involved I created a number of temporary variables to see the step by step results....

for (periodTemp = 3500; periodTemp < 31000; periodTemp += 200)
{
  for(pulseTemp = 150; pulseTemp < 4000; pulseTemp += 50)
  {
    //Checking the lookUpTable function here in the for loop.... works!
    //index1 = lookUpTable(periodTemp, pulseTemp);
    //delay(10);
    //Extended version of the calculation from the "modifyDutyCycle" function
    //adjustVal = (uword)(((ulong)dutyCycle[0])*((ulong)(lookUpTable(period[0], dutyCycle[0])))/1000);
    //index2 = (uword)(((ulong)pulseTemp)*((ulong)(lookUpTable(periodTemp, pulseTemp)))/1000);

    index2 = lookUpTable(periodTemp, pulseTemp);  //index2 = uword
    index3 = (ulong)index2;  //index3 = ulong
    index4 = (ulong)pulseTemp;  //index4 = ulong
    index5 = index3*index4;  //index5 = ulong
    index5 /= 1000;

    //Attempt #1
    //index6 = (uword)index5;   //index6 = uword
    //Attempt #2
    //blah = index5; //blah = uword
    //Attempt #3
    index6 = index5;

  }
}

Inititally "Attempt #1 failed to give the correct value"
Then I just added yet another variable "blah" - which generated the correct value.
Then I tried with no type cast with success

Step 2:
I returned to the original function and tried to get it to work - still using temporary variables.
When I simulate I get the following results...

1. There is no green/grey block on the side of the window (where you normally blace a breakpoint) at the "adjustVal = index4;" line

2. When I put the variable in the "watch" window however it seems to update the value of adjustVal

void modifyDutyCycle(void)
{
        //sam
        uword index1;
        ulong index2;
        ulong index3;
        ulong index4;
        uword adjustVal;
        //sam

        #ifdef debug
        programStatus = 0x40;
        #endif

        dutyCycleNew[3] = dutyCycleNew[2];
        dutyCycleNew[2] = dutyCycleNew[1];
        dutyCycleNew[1] = dutyCycleNew[0];

        //Calculate the extra number of timer ticks to be added to the output pulse
        //Stretch based on pulse width (off-time) not on total period

        //adjustVal = (uword)(((ulong)dutyCycle[0])*((ulong)(lookUpTable(period[0], dutyCycle[0])))/1000);

        index1 = lookUpTable(period[0], dutyCycle[0]);

        index2 = (ulong)index1;
        index3 = (ulong)dutyCycle[0];
        index4 = index2*index3;
        index4 /= 1000;

        //adjustVal = (uword)index4;      //typecast.. automatic??
        adjustVal = index4;
        //index1 = index4;

        //dutyCycleNew[0] = dutyCycle[0];

//      //Check that the new duty cycle is <100%
        if ((dutyCycle[0] + adjustVal) < (period[0] - 10))
        {
          //Return new updated duty cycle
          dutyCycleNew[0] =  dutyCycle[0] + adjustVal;
        }
        else //Error has occurred....
        {
          dutyCycleNew[0] = period[0] - 10;                     //Make the pulse width to approx. 100%
        }
}

3. When I try it on my hardware, I have a pulse output but the width is incorrect - which looks very similar to the first time I tried the funtion in main "Attempt #1"

My problem is something to do with a type cast or a memory addressing issue I think. But my results are inconsistent.

Any help on this oune would be much appreciated!!

Thanks, bye!!