gnupic: Re: [gnupic] program memory not used with addlw 0xFF (H'3FFF')
Subject:
Re: [gnupic] program memory not used with addlw 0xFF (H'3FFF')
From:
"Nestor A. Marchesini" ####@####.####
Date:
30 Jan 2007 05:44:51 +0000
Message-Id: <45BEDC6D.8040102@xinet.com.ar>
Oops, I correct myself:
FILL H'3FFF', H'800 - $
.page1 ORG H'800'
Néstor A. Marchesini
Chajari-Entre Rios-Argentina
ICQ # 50983752 colo
MSN ####@####.####
####@####.####
####@####.####
http://www.deselectronica.com.ar
Nestor A. Marchesini escribió:
> After giving them many turned to the matter and hours of simulation
> with gpsim-0.22.0 under linux Mandriva Free 2007 and MPALB 7.01 low
> winme with qemu .... eureka! I it have found the difference that
> almost me madman turns.
>
> The matter is that my program for one 16f873 has a routine that reads
> all the memory of program (4096) and is calculating two cheksums, the
> high byte and low byte, then they are compared with two values stored
> in the memory eeprom of data, if they coincide, the program continues
> your normal course, if they do not coincide (goto $) this requirement
> is of my client and serves to avoid future frauds for modifications of
> the code.
>
> I pass to explain:
>
> My program uses the page 0 (H'000' - H'7FF') and the page 1 (H'800' -
> H'FFF') but a small space stays without using, that goes from H '69D'
> up to H'7FF' I define the beginning of the page 1 with:
>
> .page1 ORG H'800'
>
> 00000680 : XXXXXXXXXXXXXXXX XXXXXXXXXXXXX--- ----------------
> ----------------
> 00000800 : XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXX
> XXXXXXXXXXXXXXXX
>
> The difference is that gpsim-0.22.0 puts the spaces not used as
> INVALID H '0000' and MPLAB like H '3FFF'
> (addlw H'FF') and this concerns fundamentally in the calculation of
> the checksum under simulation, since I
> need to simulate the code to obtain the two bytes that are stored in
> the memory eeprom of data with:
>
> .eepromdata ORG H'2100'
> ChecksumH H'xx'
> ChecksumL H'xx'
>
> The solution that I have given is to put:
>
> FILL (addlw H'FF'), H'800 - $
> .page1 ORG H'800'
>
> but, this one is not a very elegant solution.
>
> The truth is that not if this is a bug of gpsim-0.22.0 or simply
> something that was not born in mind.
> For my would be a requirement that should expire gpsim-0.22.0
>
> Regards
>
> Néstor A. Marchesini
> Chajari-Entre Rios-Argentina
> ICQ # 50983752 colo
> MSN ####@####.####
> ####@####.####
> ####@####.####
> http://www.deselectronica.com.ar
