Now I get 0.8E in place of 0.DB some improvement

required though is 0.85

 

Ok, this time multiply by 10 twice (ie. to multiply by 100)

and display only the hi-byte as result. Tell me what you get!

 

I did multiply by 100 too

I get 0.8C now

 

Ok, let's back up for a minute so I can understand your system.

Your hardware consists of two digits displaying hex after the decimal point?
When you call bcd how can you get 8E or 8C displayed?

If you pass 99d to call bcd what is displayed?
If you pass 130d to call bcd what is displayed?

 

bcd subroutine only converts to ASCII format

 

Please answer the questions.

Does your hardware consist of two digits displaying hex after the decimal point?

If you pass 99d to call bcd what is displayed?

If you pass 130d to call bcd what is displayed?

(If you no longer need help please tell me. I can always call it quits.)

 

yes I display two digits displaying hex after the decimal point
for d'99' I get 63

for d'130' I get 82

 

Now I get the picture.

Here is the algorithm:

Step 1
Multiply X_FracH by 10 (using 8 x 8 -> 16-bit result)
Save the hi-byte only as say D1 (make sure you are saving the hi-byte only)

Step2
Multiply X_FracH by 100
Save the hi-byte only as say D2

Step 3
Take D1 and multiply by 10 (only 8 x 8 -> 8-bit result required)
Save single lo-byte only as say D10

Step 4
Subtract D10 from D2 and save this byte as D0.

Step 5
Multiply D1 by 16 (simply shift left 4 bits - use single byte only)

Step 6
Add D0

Step 7
call bcd


over and out!

 

i will try this approach and let you know

Thanks for your opinion

 

Geez... This is not an opinion. This is the answer.
You take a few months to get nowhere and I give you the answer in 15 mins... such gratitude!

 

I tried by your method

It gives the answer 21.B5 and not 21.85

 

Well, I would suggest you check your code.