formatting data from Scrath Pad RAM

Jon Loldrup

Hi

After loading some position-data from my GPS into SPRAM, I am wondering how to convert it to integers?
I can easily put it into the register:

myVariable VAR Byte
GET 0, myVariable

but when I want to convert it to integer:

myOtherVariable VAR Byte
myOtherVariable = DEC myVariable

I am not allowed [noparse]:([/noparse]
How can i EVER do calculations on a digit stored as ASCII-code? Poor me

(by the way, if I manage to convert it, and I want to substract two latitudes from each other, I will still have to implement the substraction-algorithm myself, looping through individual bytes containing the individual digits of the position, as a word cannot contain the whole position. Is there no easier way?)


/jon

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/jon

Mike Green

You have to do the ASCII digits to integer conversion yourself. A simple loop will do:

theDigit var byte
theValue var byte
position var byte
convert:
theValue = 0
position = 0
loop:
get position,theDigit
position = position + 1
if (theDigit < "0") or (theDigit > "9") then exit
theValue = theValue * 10 - (theDigit - "0")
goto loop
exit:

Note that you can also use DO ... LOOP and other neater constructs.
This stops at the first non-digit and leaves position at the address of
the next character after the delimiter. If you need a word value, just
define theValue as a word instead of a byte.

Chris Savage

Hello,

A complete article describing this can be found at the following link. Take care.

http://www.parallax.com/dl/docs/cols/nv/vol4/col/nv103.pdf

also

http://www.parallax.com/dl/docs/cols/nv/vol3/col/nv83.pdf

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Chris Savage
Parallax Tech Support

Phil Pilgrim (PhiPi)

Jon,

Your query relates directly to some PBASIC enhancements I've begun lobbying for: http://forums.parallax.com/showthread.php?p=652397. As BASIC Stamps are used more and more to deal with serial protocols, it would be helpful if the language supported buffer transfers/encoding/decoding in a more I/O-like fashion. Mike's technique will certainly work, but with enhanced language features it wouldn't be necessary.

-Phil

Chris Savage

Please note also that Mike’s code will only run under 2.0 syntax on the BASIC Stamp Editor since reserved words under 2.5 were used. Take care.

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Chris Savage
Parallax Tech Support