Rockbox mail archive

• Next message: Craig Luna: "Re: Re[2]: descramble"
• Previous message: Björn Stenberg: "Serial port 0"
• In reply to: Andy Choi: "RE: descramble"
• Next in thread: Andy Choi: "RE: descramble"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Andy Choi wrote:

> (sum of all unscrambed bytes,

Ahhh, I should have guessed it was something that simple... :-)

> plus a version-specific offset)

Actually, the version offset is not needed. It was just a little mistake:

> // compute checksum
> int cksum = 0;
          ^^^
You're using a 32-bit integer for the 16-bit checksum, that's why it doesn't
match.

Here's my simple checksum program in C, using a 16-bit integer:

#include <stdio.h>

int main (int argc, char** argv)
{
   unsigned short crc=0;
   int a;
   while ((a = getc(stdin)) >= 0)
      crc += a;
   printf("crc: %04x\n",crc);
   return 0;
}

I'll make a full "scramble.c" and put it on the web page.

Good job!

/Björn

• Next message: Craig Luna: "Re: Re[2]: descramble"
• Previous message: Björn Stenberg: "Serial port 0"
• In reply to: Andy Choi: "RE: descramble"
• Next in thread: Andy Choi: "RE: descramble"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]