Boot TAQOZ in ROM from Flash (as if you had no other tools to do this)
Peter Jakacki
Posts: 10,193
in Propeller 2
I wanted to see if I could get TAQOZ in ROM to patch the Flash with a primitive boot program to set the serial and startup TAQOZ automatically from Flash at 115200 baud. But the challenge I set myself was to use nothing else other than the ROM to do this, and the PASM2 instruction encodings. With nothing but the TAQOZ boot ROM you should be able to do anything even if you didn't have any access to any external tools and compilers and assemblers etc. So I sat down for an hour or so and wrote this code below which includes the comments for the instruction encodings. Yes, I coded the image in machine code, not even assembly.
Now when I power my P2 up without SD it boots into the TAQOZ ROM immediately with the default 115200 baud.
My initial test code with comments.
Here's another version that does the same thing but builds the image along with a precomputed checksum and then FLASHER copies it across to the SD BUFFER area so that SFWRS can also write the remaining zeros just to keep the checksum intact.
Now when I power my P2 up without SD it boots into the TAQOZ ROM immediately with the default 115200 baud.
My initial test code with comments.
: FLASHER
--- Erase first 4k of Flash
0 SFER4
--- Erase and use SD buffer area to build binary image
SDBUF $400 ERASE
SDBUF
\ eeee 11000 0 0 0 L I DDDDDDDDD NNNNSSSSS
--- Set TXD and RXD modes
$FC0CF83E OVER ! 4+ ( wrpin #$7C,#$3E)
$FC0C7C3F OVER ! 4+ ( wrpin #$3E,#$3F)
--- Set baud rates based on 25MHz clock @115200 baud ( rate << 16 + 7 )
\ eeee 01100 0 0 C Z I DDDDDDDDD SSSSSSSSS
$F60600D9 OVER ! 4+ ( mov $100,#$D9)
\ eeee 00000 1 1 C Z I DDDDDDDDD SSSSSSSSS
$F0660010 OVER ! 4+ ( shl $100,#16)
\ eeee 00010 0 0 C Z I DDDDDDDDD SSSSSSSSS
$F1060007 OVER ! 4+ ( add $100,#7)
--- set TXD and RXD baud rates
\ EEEE 1100000 1LI DDDDDDDDD SSSSSSSSSS
$FC16003E OVER ! 4+ ( wxpin $100,#$3E)
$FC16003F OVER ! 4+ ( wxpin $100,#$3F)
--- jump to the TAQOZ in ROM entry point
$FD8FD02C OVER ! 4+ ( jmp #\$FD02C)
--- Calculate checksum for 1kB Flash
" Prop" @ 0 SDBUF $400 ADO I @ + 4 +LOOP - SWAP !
--- Write 1kB to SPI Flash
SDBUF 0 $400 SFWRS
;
Here's another version that does the same thing but builds the image along with a precomputed checksum and then FLASHER copies it across to the SD BUFFER area so that SFWRS can also write the remaining zeros just to keep the checksum intact.
: IMAGE
$FC0CF83E ,
$FC0C7C3F ,
$F60600D9 ,
$F0660010 ,
$F1060007 ,
$FC16003E ,
$FC16003F ,
$FD8FD02C ,
$AB282C3A ,
: FLASHER
SDBUF $400 ERASE
' IMAGE SDBUF 36 CMOVE
0 SFER4 SDBUF 0 $400 SFWRS
;
Comments
I'm adding a boot from flash feature to TAQOZ reloaded so it will backup the current image into flash, and patch in a second stage loader into the 1kB primary flash boot page. I've never bothered before because I find being forced to do two stage flash booting is ugly code-wise.
Maybe this second stage loader is something we could always burn into the Flash boot area and then it could check for a valid image to load. However if there isn't an image it needs to check the SD boot etc. I'll see if I can make a standard loader for any valid P2 binary.
And that really f...s up the SD card and I need to reformat when I do not want to start TAQOZ but just the current bix file.
maybe backup should use bix as standard and a backup mbr would write the mbr?
not really important but - hmm - annoying,
Mike
Good point because I always use preformatted or SD formatted cards but MS format ignores all this and does not leave any space before the start of the partition. That would be a problem then when my default BACKUP writes to this area. So I need to check the partition info and if there is blank space I can save it there, as I like to, but if not, then to assume it is the BIX file. Raw sector load is faster too btw. You probably already know that there are various keyword shortcuts built into BACKUP, including BACKUP BIX and BACKUP FLASH and BACKUP MBR etc A ^B does a BACKUP MBR as does typing BU.
I have never seen MS format not leave the space before the partition. Is it another format program you ae using???
This has always been the case as it does not treat the SD card as anything special which the SD Card Association specifies. I will check this once again with the latest WIN10 but I don't expect to see anything different.
Here is a 128GB card that was properly formatted, in this case using TAQOZ.
I have always used windoze to re-format my SD cards, mostly via the slow method, using windows explorer. I have always thought (maybe I need to verify this) that windows placed the partition some significant number of sectors later ie leave some significant space. I usually use 32KB sectors which is the default for the cards i've used (1GB-16GB)
My FAT32 FORMATTER in TAQOZ conforms to the recommendations and can format cards >32GB as FAT32 with cluster sizes up to 64kB. For embedded work we don't have tens of thousands of files and it is very difficult to use up even the smallest card, so 64kB clusters are more efficient although with my file system it makes no real difference.
Yes, if we get to 1,000 files I think there's a major problem. It's the same as files being fragmented - not going to happen on an sd card with what we use it for. I'm sure someone can come up with a case, but for us, who cares.
my guess is that when I add easyfile you do a BACKUP and that does write the mbr. So my wish would be to have the standard BACKUP to leave the mbr alone, except if actually asked for.
Maybe I am completely wrong with my assumption I still have a hard time to read FORTH.
Mike
Well, it's not actually the mbr per se but any raw sector with a entry in the mostly unused mbr pointing to this sector. So since SD cards have several MB free before the start of the FAT32 partition, I choose to use sector 1. This does not impact any files or anything else and is the least intrusive. The problem is with cards that have been formatted in Windows which does not leave this unused space and because my software has not bothered checking if this exception is the case. All I will do now is check for improperly formatted cards (for SD cards that is) and save to another spare area or BIX if it is available. The raw sector method is the the most efficient and least intrusive method, so it is not my "fault", it is my default
As for a COBOL programmer having a hard time reading Forth, it is understandable, after all, in COBOL you would write Hello World a bit like this:
IDENTIFICATION DIVISION. PROGRAM-ID. HELLO-WORLD. * simple hello world program PROCEDURE DIVISION. DISPLAY 'Hello world!'. STOP RUN.whereas in Tachyon Forth:
To print that 10 times:
The console shows this:
So I can see why you are having a "hard time"
The problem is that once TAQOZ is on the SD I can't use it for anything else anymore except I reformat it. If BACKUP would just save to say bix I would be able to overwrite the file or rename it, but as far as I got, the SD is basically booting into TAQOZ if I need/want to, or not.
It is not really a major problem, SD's are cheap, but getting them in and out is sort of complicated when the eyesight is leaving me and my hands are trembling a lot lately.
I do LIKE the ability to save TAQOZ to the mbr and prevent users to overwrite it by accident, but it should not be the only way to use it.
I also understand that you do not often use other languages, so you might not encounter this problem. But one of my goals since a while is to use TAQOZ concurrently to other software and there seems to me is the problem I have with the mbr and you don't.
So the SD is working even when formatted with windows, it is just TAQOZ taking it over and to run something else I have to get the SD out while booting or I am stuck in TAQOZ.
Maybe some of your TAQOZ on-liners might help me to load another binary from the TAQOZ prompt, overwriting the already running TAQOZ, that would solve the problem also.
Mike
Examples are:
BACKUP BIX
BACKUP _BOOT_P2.BIX
BACKUP DISABLE
BACKUP FLASH
I don't understand why you think you can't use the card anymore though. When I plug the card back into my PC it just sees a normal FAT32 card and files while TAQOZ is hidden away and protected. This means I can supply cards in products that can be removed and used in a PC and reinserted back into the P2. They can delete all the files they want, but the mbr file is protected. Once they format a card for whatever stupid reason then all bets are off anyway.
There are no restrictions with the way TAQOZ backs up, only options. I use the options that suit me. Most others use the BIX file.
I do understand that using the boot sector allows you to have TAQOZ installed without worrying that a user using the SD on a PC kills TAQOZ. That is a nice feature and I see and understand your goal there, but my goals are slightly different.
I seem to have problems getting what I want to say into your head. So I will try again.
I would like to use TAQOZ, but not 'just' TAQOZ. The word I like to use is coexistence.
And as far as I got a SD card with TAQOZ installed will boot into TAQOZ even if I do not want to boot it, but something else in a existing bix file on SD.
I might be doing something wrong, that is my current assumption. But your 'standard' installation is hijacking the boot sector and I am lost in solving that problem.
I could get around this - with your help - if you
a) give me a hint how to remove the boot sector booting after installing TAQOZ on a SD. The Backup used in your current setup seem to assume that I want to boot into TAQOZ all the time. And I don't.
b) alternative give me some hint how to load some Pnut or FlexProp created binary from TAQOZ thus overwriting TAQOZ from HUB 0 upwards.
c) or just tell me that coexistence is not something you support and I will need to abandon my quest of being able to use TAQOZ and non TAQOZ software from the same SD card and the same P2 without changing the SD card
Mike
Notice that in the disk report, in the MBR section that the first sector of the first partition is $2000. So after the MBR there are 8191 sectors that are not used and are hidden. Whether there is anything there or not, it makes no difference to the rest of the system.
Now, back to what mainly has concerned you is how TAQOZ can co-exist with other software which is an entirely different matter. This is where TAQOZ does actually hijack the first 64k of P2 memory. How now brown cow, can we have independent user software written in any language co-exist with TAQOZ?
Hmmm, well a practical user case beats any hypothetical case but I'm guessing that as long the user code does not use the first 64k then there shouldn't be any problem. But most startup code assumes it should use cog 0 for starters, so maybe this is one area where TAQOZ could tuck itself away in COG 7 perhaps, then check for user code to run after it has already initialized itself. Effectively, this is no different from any other INIT task that it may have in its startup list. If now rather than calling the user startup code, it instead does a coginit 0 with the user code, then all should be well. User code can run while avoiding the first 64k except for the configuration and mailbox area. One mailbox section could be the equivalent of the serial I/O of the TAQOZ console so user code could ask TAQOZ to do this or that and even handle the filesystem etc.
Is this getting closer to what really concerns you? Do you have code that you would like to run this way?
DISK REPORT:
TAQOZ# .DISK --- CARD: SANDISK SD SL08G REV$80 #188035386 DATE:2016/7 *** OCR *** VALUE........................... $C0FF_8000 RANGE........................... 2.7V to 3.6V *** CSD *** CARD TYPE....................... SDHC LATENCY......................... 1ms+1400 clocks SPEED........................... 50MHz CLASSES......................... 0 1 0 1 1 0 1 1 0 1 0 1 BLKLEN.......................... 512 SIZE............................ 7,761MB Iread Vmin...................... 100ma Iread Vmax...................... 25ma Iwrite Vmin..................... 1ma Iwrite Vmax..................... 45ma *** SPEEDS *** LATENCY......................... 211us,278us,219us,228us,219us,230us,240us,205us, SECTOR.......................... 356us,376us,375us,385us,379us,387us,397us,361us, BLOCKS.......................... 3,165kB/s @300MHz *** MBR *** PARTITION....................... 0 00 INACTIVE FILE SYSTEM..................... FAT32 LBA CHS START....................... 1023,254,63 CHS END......................... 0,0,0 FIRST SECTOR.................... $0000_2000 TOTAL SECTORS................... 15,515,648 = 7,944MB 00170: 0000_0000 0000_0001 0002_0000 506F_7250 '............ProP' *** FAT32 *** OEM............................. TAQOZ P2 Byte/Sect....................... 512 Sect/Clust...................... 16 = 8KB FATs............................ 2 Media........................... F8 Sect/Track...................... $003F Heads........................... $00FF Hidden Sectors.................. 8,192 = 4MB Sect/Part....................... 15,515,648 = 7,944MB Sect/FAT........................ 7,576 = 3MB Flags........................... 0 Ver............................. 00 00 ROOT Cluster.................... $0000_0002 SECTOR: $0000_5B50 INFO Sector..................... $0001 = $0000_2001 Backup Sector................... $0006 = $0000_2006 res............................. 00 00 00 00 00 00 00 00 00 00 00 00 Drive#.......................... 128 Ext sig......................... $29 OK! Part Serial#.................... $50AD_0021 #1353515041 Volume Name..................... P2 CARD FAT32 ok TAQOZ#Examine MBR (sector 0 ):
The ROM boot code loads this into hub from $0 and jumps to it (I would need to check, but I think after it is loaded into hub $0 it copies a block to cog 0 and executes that - but this is actually irrelevant for this discussion - there are full details in another thread).
So what we have is the ROM will boot a program (whatever that may be) that is now stored in a fixed location on the SD. It is really no different to booting _BOOTP2.BIX under FAT32. The program saved as _BOOT_P2.BIX will run. To make it boot a different program requires you to overwrite the program stored in _BOOT_P2.BIX.
So, what you need to do is write a basic program that will ask the user (or check a pullup on a pin or similar) to load alternative program(s). One of these can be TAQOZ. As long as this program can find the desired program and load it you're fine to go.
The second issue you raise, is multiple different programs running on the P2 at once. As you know, this is totally dependent on how the program(s) are written - can they share all P2 resources?
Here is where the mailbox approach is key. Without it, program(s) are never going to be truly sharable unless written specifically to co-exist together. But no-one is interested in the mailbox idea!
And finally, and this is where I know your interest lies, TAQOZ and Z80/CPM cannot co-exist, at least for now. They both require code space in hub in the lower 64KB. This is because both Peter and I use tables of hub addresses with 16 or less bits (I use 12). If we had to adjust every operation to permit a fixed offset into another 64KB block, we would both suffer a huge speed hit to our code. neither of us are prepared to accept this, for now at least. There are other issues, but this is currently the single biggest one.
I try again.
I currently can compile code with FlexProp and leave space for TAQOZ in the first 64k, start my program in Cog1 at $1004 and jump COG0 into the ROM TAQOZ, use the smart pins to grab TAQOZ I/O pins, send some commands to TAQOZ redirecting the TAQOZ command to a mailbox at $1000-$1004 and it is working fine.
I am able to do that since rev A with the ROM version. But I would like to use TAQOZ reloaded not the ROM version. And there I seem to hit a wall because when I install TAQOZ on a SD this SD will boot into TAQOZ and I do not need that at all.
So my need is to have a current TAQOZ on SD as a file, without TAQOZ writing itself into the boot sector stuff on the SD card every time I (or Peters code) does a BACKUP after putting some words into TAQOZ.
And sadly the code I can grab from Peter DOES write itself into the boot sector version and NOT just use the bix file. I can access/rename the bix file, but am not able to prevent TAQOZ from starting up after reset.
And YES @"Peter Jakacki" even a standard windows sd has no problems with your boot solution, and YES even I can not accidently overwrite TAQOZ there in the boot sectors. It is pretty cool for your applications, but for my applications it is really a hinderance.
I do NOT want to boot TAQOZ after every reset. Really. I do not. And I do not really want to switch SD cards every time I want to play with TAQOZ.
I just want to run it as a Application, like @Cluso99 is starting CP/M as a Application. NOT taking over the boot stuff.
I am aware that CP/M and TAQOZ use the same 64k, I would be fine with being able to start either or and not both at the same time. The concurrent thing I already can handle with FlexProp leaving room for TAQOZ, as long I use the ROM version and just do no BACKUP.
The problem is that TAQOZ reloaded saves itself as 'boot sector loaded' not' bix file loaded' and then my own program will not start because the P2 rom starts the boot sector version before a bix file, so I am - hmm- doomed(?) after installing a full TAQOZ, it takes over the boot routine and the SD card.
I am not sure how to describe this more detailed, maybe I need some Interpreter between German and Australian. My English seems not to be good enough.
Enjoy!
Mike
Why not just overwrite the signature at $170..$17F in sector 0 of the SD card after a Backup in TAQOZ. Maybe generate a word in TAQOZ that can do that.
Andy
OK. I now understand the problem.
Peter will need to explain how to save to a file, or even the unused sd sectors, without updating the MBR with the "boot identifier".
Now, if you load the TAQOZ binary as _BOOT_P2.BIX then that will boot unless an MBR boot is present. If for some reason you had done a BACKUP MBR or BU or ^B at some stage and now you want to get rid of it then BACKUP DISABLE is all you need to do. That wipes the MBR signature.
All the commands and all the options are there so there are no restrictions. You can make your code the BIX file and have it load TAQOZ or whatever you want.
BACKUP DISABLE was what I was looking for.
Thank you.
Mike