CRC 16-bit and 32-bit 
Author Message
 CRC 16-bit and 32-bit

I'm getting extremely frustrated with trying to find the 16-bit CRC used
in IEMSI sessions.   It is supposed to use a $1021 divisor, but I have
about 5 different CRC source codes now, all of them are "standard" and all
give different answers (none of which is correct).

Alls I have that actually works is some 6502 source code, and I'm having
a heck of a time translating it to anything useful.
Can someone translate the following into TP 7.0?   I was kinda confused
by the ROL as the only way I could think of doing it was with a string
representing the binary number and just using a lot of Copy's, but that
would be too slow...

chr = character to update crc16 with
tmp = temporary storage of the chr for manipulation
crc16 = the crc16 word used by IEMSI and X-Modem CRC.

        LDA chr
        LDX #$07
        STA tmp
nextbit ASL tmp
        ROL crc16
        ROL crc16+1
        BCC noxor
        LDA crc16+1
        EOR #$10
        STA crc16+1
        LDA crc16
        EOR #$21
        STA crc16
noxor   DEX
        BPL nextbit



Wed, 18 Jun 1902 08:00:00 GMT  
 CRC 16-bit and 32-bit


Wed, 18 Jun 1902 08:00:00 GMT  
 CRC 16-bit and 32-bit

Quote:

>Alls I have that actually works is some 6502 source code, and I'm having
>a heck of a time translating it to anything useful.
>Can someone translate the following into TP 7.0?   I was kinda confused
>by the ROL as the only way I could think of doing it was with a string
>representing the binary number and just using a lot of Copy's, but that
>would be too slow...

Here you go sir.  The assembly files are setup for Microsoft Assembler
6.x, but could easily be ported over to Tasm.
http://www.webworldinc.com/joejared/index.htm
ftp://webworldinc.com/pub/joejared/
--- Fidoknot v1.0



Wed, 18 Jun 1902 08:00:00 GMT  
 CRC 16-bit and 32-bit


Wed, 18 Jun 1902 08:00:00 GMT  
 CRC 16-bit and 32-bit
begin 644 crc.zip
<uuencoded_portion_removed>
74U!+!08`````!``$`-P````%$``````Y
`
end


Wed, 18 Jun 1902 08:00:00 GMT  
 
 [ 5 post ] 

 Relevant Pages 

1. Convert 32 bit component to 16 bit ??

2. BDE 32-bit & 16-bit

3. 16 bit ODBC drivers in the 32 bit environment

4. 32 bit bde with 16 bit odbc

5. Delphi/BDE 16 bit VS 32 bit

6. Upgrade 16-bit application to 32-bit

7. Upgrade 16-bit application to 32-bit

8. 16-bit to 32-bit

9. 16-bit Application and 32-bit ODBC

10. Sybase : slow using 32 bit - fast using 16 bit

11. 16 bit and 32 bit BDE with same table

12. 32 bit ops in 16 bit real mode TP

 

 
Powered by phpBB® Forum Software