32 bit seconds math (how do I include the upper 16 bits?)

[HenrikOlsson]

Hi Dwight,
No, that sort of info is not in the manual. I don't remember from where I got it but I'd be surprised if it wasn't from one of Darrels post.

Anyway, yes, normally what you do is multiply two 16bit number which results in a 32bit result then, imediately after, you execute the DIV32 which will divide that 32bit result by the 16bit divisor. The trick is to know that when you do the 16*16bit multiplication the result of that ends up in system variables R0 and R2. Once you know that there's nothing stopping you from manually loading those registers, the DIV32 function will not know the difference.

If you have a total of 1,125,000 seconds in your ABCD variable, looking at that in hex: 0011 2A88 what goes in R0 is 11h (17) and what goes on R2 is 2A88 (10888).
17*65536+10888=1,125,000.

I think there might be a possible issue with the code as posted. When the number of seconds passed is less than 86400 (one day) then owDays will be 0 and the FOR-NEXT loop subtracting 86400 seconds per day will execute 65535 times. I think the result will still be correct since it'll just wrap around but it may take a fair bit of time..... You might want to enclose that FOR/NEXT loop in an IF/THEN block checking if owDays > 0.

/Henrik.