Author Archives: Marcel

QL-SD, QL-microSD and (S)GC battery

QL-SD

So, a short update on QL-SD, I have spent another few hundred Euros on parts and everything has arrived except the package with the SD-card connectors, which seem to be lost in the mail. These are needed for the double-SD adapters, which I expect will be pretty popular. Instead of waiting for them to show up I have ordered another batch of 100 connectors elsewhere which should hopefully arrive in 1-2 weeks.

QL-microSD

Urs was interested in the micro-SD variant that I have hacked together previously and initially I didn’t want to produce them. But then I wanted to try out another CAD package, KiCad, and this project seemed like a good way to start with it. I haven’t obsessed about this as much as I did on the MDV board and again I ordered the whole batch without having a prototype first, so if it works I have lots of microSD adapters to offer and if it doesn’t fit in the end I have not 😉 But again I have a good feeling about this. These boards, too, should arrive in 1-2 weeks. Here’s a sneak preview:

(S)GC battery

Finally, this is apparently something everybody who ever built QL hardware will produce as some point: a replacement for the SAFT 40LF220 battery. In my case I just wanted to test another PCB service as they had a good offer going and as I finally got myself my own SuperGoldCard (donated by Jochen Hassler, thank you soooooo much) I needed a new battery solution anyway. The only difficult thing was my inner perfectionist rebelling against just using some wire for the four contacts, so I actually spent a few hours sourcing perfectly milled pins for them:

These can be ordered along with a QL-SD for a small price when I’m eventually ready for sale.

QL-SD update

Just a slight update before I go on holiday for a week. The design of the MDV adapter board has been finalized and I already have the PCBs here:

The board can be built into four different configurations of which I will probably offer two:

  1. Single slot drive using a ready-made daughter board soldered onto the MDV board:
  2. Double drive where one slot is soldered directly onto the MDV board and the other is on a daughter board stacked on top of it.

    The initial plan was that the upper slot is by default “WIN1” and the lower slot “WIN2”. But turns out the card in the lower slow is difficult to change when the upper slot is occupied, so I think it makes more sense to have a permanent “WIN1” in the lower slot and use the upper slot for data exchange. In any case, there are simple jumpers on the board so the final decision can be made by the user, no soldering necessary.

The other variants are fall-backs that I added in case the two versions above made problems because when ordering 50 boards without having a prototype first it’s good to have some options. Looks like I don’t need them, though.

A few parts are still on their way from China and a few more parts I need to order from the US after my holiday. I have bought 300 LEDs from China and initially I was very happy with them, but compared to brand-name LEDs they are a bit more “spotty” and less diffuse/homogeneous, so I won’t use them after all. Which also means that the colors are not yet defined, if you’ve got anything against amber/red then speak up now or forever hold your peace 😉

Speaking of LEDs, I have added some solder pads where one can connect external LEDs (in one case I wired the original MDV LED to it). This is for the tinkerers and not used by default.

So, the project is still moving along, stay tuned.

Cueshell – The definitive file manager for the QL

24 years ago Albin Hessler released his file manager Cueshell into the world. It was and still is one of the most advanced programs for the Pointer Environment ever written, featuring a Multiple Document Interface (smaller directory windows within the larger application window) and drag&drop file management. Managing large directory trees became incredibly easy and I still use it very frequently. It was truly way ahead of its time and this might have been its problem, as commercially I think it wasn’t as successful as hoped. Some people might remember that we did a special QPC+Cueshell promotion bundle in the early days to help adoption, but I don’t know how well those did.

Some 13 year ago I made a feebly attempt to update it to the new WMAN2 system palette, but because visually it was so advanced and non-standard I never truly managed to do a version that would do it justice, so I still use the 4-colour version. It has aged quite well however:

A few days ago I asked Albin if he could provide me with the latest manuals etc so I could release it for free and he readily agreed. The manual, too, turned out to be very beautiful, with many screen shots and illustrations. So today I present to you the latest version Cueshell v2.14, I hope you take some time to check it out because it really deserves it.

Cueshell 2.14
Cueshell manuals

QL-SD news

(Summary at the end if you’re not interested in the details)

Some people know that I’ve been working for quite some time on making the QL-SD work with the late Stuart Honeyball’s masterpieces, the GoldCard and the SuperGoldCard. And I seem to have succeeded, but the way to success took a lot more time than I anticipated. A mix of simultaneous problems in the hardware connections, bus signals, driver software and CPLD chip made for quite a difficult debugging experience. Small changes in the CPLD code that should not have any logical impact made the thing not work anymore at all, etc. Hardware is weird! Good thing I don’t have hair anymore anyway.

But now that the problems appear to be solved there is no supply of new QL-SDs to spread the joy! Dave mentioned he’s working on an external version, but I quite like the internal ones and quite frankly after all this work I didn’t mind the idea of generating at least some small revenue for my time for a change. So two weeks ago I decided to have a go myself and designed a new replacement board that is a bit easier to manufacture than the originals but other than that very similar. I ordered a batch of 50 gold plated PCBs on the good faith that they will simply work and yesterday DHL express delivered the precious cargo:

I soldered one prototype and, surprise surprise, it worked flawlessly from the get-go! Pure adrenaline 😉 The second board, made with lead-free solder this time, was a bit more stubborn but eventually succumbed to my superior solder skills (just kidding). Here’s a sneak peek:

Connoisseurs will notice that I’ve used bigger traces and components on the PCB to make it easier to produce, the space is there after all. What I haven’t finalized yet is the design of the MDV daughter board, which is really trivial but I wanted to wait if my main board worked before I invested even more money! Also I had the idea to provide a dual-card board and even made a working prototype out of my existing QL-SD adapter:

QL-SD dual card adapterQL-SD dual card adapter

What I didn’t anticipate were the small rails holding down the MDVs in the top of the case, so the whole thing almost but doesn’t quite fit. I’m thinking about lowering the main PCB to be flush with the screw-posts but I’m not sure how mechanically sound this would be and if it’s really worth the trouble. Tell me if you’re interested! I also tried a completely different approach, but that was more a thing done in jest, using an existing ventilation hole in the QL case (that sticker was actually put onto my QL about 28 years ago 🙂 ):

TL;DR

  • QL-SD works great now with GoldCard INGOT 5 including Tetroid clone (I think INGOT 6 already worked before) and SuperGoldCard. The original hardware only needs an update of the CPLD code for this. I will probably provide an update service for a fee, tell me if you’re interested.
  • I have submitted my fixes and changes to the driver to Wolfgang (thanks again Wolfgang, without his driver I wouldn’t have started my quest!), he said he will check them out soon.
  • I started producing a new batch of QL-SDs, though hand soldering them is a bit tedious and I will have to see if I can speed up the process. Price has yet to be determined.
  • I created a prototype dual-card adapter, but mechanically it’s not sound yet and even if these problems are overcome it might be difficult to produce. Anybody interested in this? It is 100% compatible with the original QL-SD, of course.

So, tell me if you’re interested or have any other comment.

Debugging Minerva

Martyn Hill recently discovered a bug in later versions of Minerva, but couldn’t quite pin it down. I thought it might be nice to write up a little tutorial about how I try to tackle these kind of problems.

The most important thing of course is being able to reproduce the problem, which was the hard part here as I haven’t had any networked QLs for 20 years. I didn’t remember any of the commands and devices used and somehow one ULA died along the way, which didn’t exactly help matters. But in the end I got it going and yeah, I could get it to crash:

QL1:
  NET 1
  SBYTES neto_2,131072,32768

QL2 (the one that will crash):
  NET 2
  LBYTES neti_1,131072

The “LBYTES” never returns here. The first thing to do in these cases is loading QMON and simply activating it

LRESPR flp1_qmon
qmon
Qmon> g

This way we will ideally break into the debugger if anything fishy happens. So, try the repro again and bingo:

Excuse the quality, at this point I didn’t know I will be writing about this, I made the picture just in case I need any data from it later in the process! Two things will look odd for people experienced in QMON, the “__000000” and the “MULS.L”. The first prefix “__” is an extension that displays addresses relative to the job base, which makes debugging jobs so much easier. In this case the JOB is SuperBasic, which has a start address of 0, so we’re actually at the absolute address 0 here. “MULS.L” is a 68020 instruction and now I can be glad I did this on a BBQL because this way the crash happened as early as possible. I think both the job-relative and the 68020 features were added to QMON by me some 15 years ago and were probably never released, but it doesn’t matter for this exercise.

The next step is to look at the stack, hence the “d2 (a7)”. There we see “00000D28”, which could potentially be a ROM address. In this case I have assembled Minerva myself so I have the corresponding _MAP file ready, which is invaluable when debugging assembler code:

SECTION   00000C9C  00000D78                                            IO_SERIO

          00000C9C  00000D78  SRC_MINERVA_IO_SERIO
                    00000CA8    IO_SERIO
                    00000CAA    IO_RELIO

This looks legit, so we open the source file “io_serio_asm” and also have a look into DISA to check which instruction exactly is there

Bingo, there is a jump instruction directly in front of it, so we’re at the right place. We look for it in the source code

callit
        movem.l d4-d5/a1/a4,-(sp) save our registers
        jsr     (a4)            call the test/fetch/send routine
        movem.l (sp)+,d4-d5/a1/a4 restore our registers
tstret
        tst.l   d0              ensure set ccr before returning
        rts

It jumps to a4 and, referencing the picture above, a4 is 0. We can also see the contents of the saved registers on the stack “0000000F” for D4, “00000000” for d5, “000b6568” for a1 and again “00000000” for a4. The next long word is “00000d52” which again looks like an address, so where are we coming from? Again, looking it up in DISA and then searching the instruction sequence in the source we end up at the label “headr1”

headr1
        bsr.s   io_pend         see if there is a byte available yet
        bne.s   setd1           if not, or there's a problem, return updated
        not.b   d1              check the value of the waiting byte
        bne.s   err_bp          error if it isn't $ff

Ah, so we were calling io_pend, let’s look at this code

io_pend
*        moveq   #0,d0           test routine is the first element
        bsr.s   vectest         set up test routine address
        bra.s   callit          go do it

Lau commented out the “moveq” because he thinks d0 is 0 here anyway. We have a look at “vectest”

vectest
        exg     a4,d0
        btst    #0,d0           test lsb of address register
        exg     a4,d0
        beq.s   vecrel          if zero, go do relative vector
        move.l  -1(a4,d0.w),a4  pick up serio's absolute vector
        rts
vecrel
        add.w   (a4),a4         add relio's relative vector to get absolute
        rts

where we see that D0 is used as an index but should be the same going out as going into the function. No we have a look at the QMON screenshot and see that D0 is actually “00000058”! So the assumption that it would be “0” doesn’t hold and this explains our crash. We include the “moveq” in the source code, reassemble and burn the EPROM and yes, it doesn’t crash anymore. Happy days 🙂

The whole process maybe took 10 minutes, it was actually a pretty straight forward. For sure it took a lot longer to write it up 😉 I know Martin has been working at this for quite a bit, so I thought I’d share my method in the hopes that more people can find and fix these kind of bugs in the future.

For everybody who is not at home assembling Minerva I have added an English and German version with the fix here:

Minerva 1.98 with I/O fix (English/German)

Clonetastic: QL-SD clone working with GoldCard clone

Every since I got my QL-SD interface I was annoyed with the driver support, especially on the PC side. I didn’t manage to fill the SD card without destroying the image one way or another. Then came Wolfgang Lenerz awesome QLWA compatible driver and now it works like a charm.

But only on my original QL, the QL-SD always had problems with the (Super)GoldCards of the world and especially with my Tetroid GoldCard clone, where it didn’t work at all. The general assumption was that the QL lines are too noisy and the chip employed on the QL-SD too fast so that all sort of trouble happens. To check for this I started building a QL-SD clone (thanks to Peter Graf for open-sourcing the hardware!) using a slightly older Xilinx XC9572XL architecture. But before I could finish that I finally did some measurements myself and found something interesting concerning my GoldCard:

When the ROM area is accessed the CPU puts the address on the bus and the motherboard generates the ROMOE (ROM Output Enable) signal. This is fed to the ROM chip, which in turn outputs the data for the address on the data bus. When the data read is finished, ROMOE is disabled again, the ROM stops driving the data bus and then the next address is put onto the address bus. Pretty simple. But now let’s look at this on the GoldCard, upper signal is ROMOE, lower signal is A0:

ROMOE/A0 signals

ROMOE/A0 signals

One can clearly see that the address line A0 begins to change even though ROMOE at this time is still high! This doesn’t harm much when accessing a ROM, it would just output some garbage which will be ignored anyway, but with QL-SD it’s a bit more complicated. This illegal state can trigger actions in the interface that were not requested by the software, especially when the driver code is executed from the ROM, too, as then obviously there are many more accesses to the ROM area. This also explains why some people apparently had more luck getting it to work when the driver was purely executed from RAM. Anyway, this can be fixed fairly easily. Problem is, I don’t have a Lattice programmer to change QL-SD, though one is on its way from China right now. But I did have my clone, so I worked with that:

Looks pretty wild, right? But what can I say, despite the long lines and everything, once my changes to the Verilog code were uploaded to the chip the interface began to work, without a single fault so far, even when the driver is executed from the ROM. With the original Verilog code my clone didn’t work at all, so it’s definitely not just the different chip.

Next step is waiting for my Lattice programmer to arrive (apparently today it was put onto an Airplane) and to reprogram the original hardware. I’m fairly confident that this will work, too, at least for the GoldCard. So far I still was not able to acquire a SuperGoldCard :-(, so I cannot tell in how far this would help there, too. Stay tuned!

Sandy SuperQBoard – now in HD!

A few years ago I got my old QL system out of storage and into working condition, but after 20 years of using QPC I completely forgot how much of a pain it really was. I never owned any of the Gold Cards, in fact all my BBQL hardware (640KB internal memory expansion, a 192kb battery powered static RAM-disc card (“MOS-Card”) and a Sandy SuperQBoard clone) were all hand-built by my late father, together with his work colleague Jochen Hassler (he jokingly called the Sandy clone “Herbert” card in the source and documentation, after my father).

Two major points I didn’t remember was how painfully slow the QL was and also that my setup could only read and write DD discs. Regarding the later point I found schematics of a HD capable version years ago, also designed by Jochen, and I went and checked them out. Though it’s not much, it took me a while to find all the differences in the schematics and understand what they did (remember, I’m not a hardware person!). I started to design some “upgrade board”, but many months passed without doing much of it and eventually I was able to buy one of the new Tetroid Gold Card clones (finally! Not the SGC I hoped to get one day, but at least progress 😉 ), so both of my problems were solved in principle (if only my QL-SD worked with it, but that is a topic for another time).

But the idea of a hardware upgrade for my old and trusty Sandy card still intrigued me and after Christmas I said “what the hell” and just tried it. This was the prototype:

And believe it or not, despite all the noise and the inherent problems with this solution it still worked 🙂 Not from the get go, there were some connection problems, but eventually. So I went back to my PCB design. Originally it was supposed to be a little board that can be fit somewhere on the Sandy board with lots wires to different parts of the board, but after realizing that almost all signals I need are already available on the WD1772 pins I designed it as an intermediate board between the controller board and the chip. In fact there is only a single additional line needed, the signal that ultimately selects between DD and HD, everything else is neatly handled by the design. So two days before new years eve I sent it to China for manufacturing and only 4(!!!) days later I got this back (shoddy soldering all mine):

Of course in my enthusiasm I forgot to include the decoupling capacitors for the two chips, but with the short lines, a huge ground plane on the bottom and the WD1772 capacitor so close-by it apparently doesn’t make any difference. So after all this time and effort this is what the result looks like and what can I say, it works like a charm:

Interestingly the same board could potentially be used to upgrade a TrumpCard, in this case however changes to the PAL and an upgraded TrumpCard driver would be needed, too. Unfortunately I currently don’t have any TrumpCard sources, even though considering that both use a WD1772 chip the difference to the Sandy driver should not be that great. The Sandy HD driver itself is a prototype that was also never released into the wild, I think, and it is unfortunately too big to still fit into 16kb (as it includes the ATR device), so combining it with TK2 is somewhat of a challenge. But then, nobody who every combined these two (except TT) had the sources before 🙂 So, let’s see what the future might bring…

Anyway, this was my little quest, thanks for reading and a happy new year!

QMenu v8.03

Thanks to Jochen Merz I can now release a very new version of QMenu (menu_rext), along with the original manual: QMenu download page

Earlier releases done by me had a few annoying bugs which I was now able to track down. The problems actually were not located in the QMenu source code itself, but Jochen had to slightly adapt his copy of the Tony Tebby libraries, changes which were sadly missing in my copy of those libraries… a pointer was not saved and thus all sort of havoc ensued. This was for example why the “file extension filter” in the file select box wasn’t working in any binary assembled by me.

Furthermore I tried to address the incompatibilities with QDT. It took me quite a long time to realize that the problem is actually pretty simple: QMenu v7.68 added a “move” button to the LIST dialog and of course this increased the size of the dialog somewhat. No big deal, right?

Well, QDT, not having any main window, employs a special EXE to invoke QMenu and the window outline this EXE provides only has enough space for the smaller pre-v7.68 menu… in v8.03 I have now included the old menu as a fallback option for this special case when the newer menu doesn’t fit. This way QMenu seems to be compatible to QDT again, but if you know of any more problems please contact me or write on the ql-users list.

Updated QPC2 for Mac OS X

Peta Jäger sent me an update for his QPC2 for Mac bundle. It comes in at a hefty 544MB and includes the latest Black Phoenix distribution, QMovie and QBase. Get it from the QPC downloads page.

QPC2 4.0.5 for MAC

QPC2 4.0.5 for MAC

Category: QPC

SBasic Bug Boogie

This will be a highly technical post, but as the last one got some positive feedback, why not 😉 Recently on the QL-users mailing list there was a bug discussed that if you load new Basic extensions using LRESPR within a basic PROCedure or FuNction SBasic would sometimes crash.

Wolfgang did some initial research and found the place where things eventually go wrong but wondered if it’s really worth the effort to try and fix it. And rationally speaking it’s absolutely not: the bug is relatively obscure and the SBasic interpreter code in SMSQ/E is so complex that it takes me huge efforts to barely understand parts of it. But being stubborn I went ahead regardless, starting with the findings Wolfgang already provided.

During the search I found references to bug fixes in the code I made 10 years ago about which I have no recollection whatsoever. The fixes are so deep in the innards of the beast that I apparently once understood what it does, but not anymore. So this time I want to record a few thoughts so maybe I don’t have to relearn everything from scratch next time.

Parser

The SBasic main loop starts at sbm_loop (main_asm). It provides the command line interface and it’s the place where I implemented the command line history. Entering a command using the keyboard or loading a program from disc is basically the same: the strings are read from the channel and fed into the parser stage (parse_asm). It does some basic error checking and translates the commands into numerical “parser tokens”. So 5 spaces for example become $8005 and “IF” becomes $8103. The tokens are defined in the file “parser_keys”.

Compiler

When the program is RUN the action starts at sb_execute (execute_asm). First it calls the compiler at sb_compile (compile_asm) which translates the “parser tokens” into “compiler tokens”. Compiler tokens are similar but not entirely like the parser tokens: “END” and “FOR”, for example, are two tokens in the “parser tokens” space, but when preparing for execution combined into a single “END FOR” token in the compiler token space. These tokens are found in the comp_keys file.

In the next stage the compiler tokens are compiled into operations (compop_asm). This creates the actual stream of operations that is later executed by the interpreter. Pretty much all control structures like GO TO/GO SUB/PROCedure, FuNctions, SELect, FOR/REPeat loops and even IF THEN ELSE are compiled into (conditional) GOTO jumps. At this stage these jumps are still addressed by line- and statement number.

From the operation stream a statement table is built (cmpstt_asm). This table translates line/statement numbers into absolute addresses within the stream.

During the next stage (cmpadd_asm) and using the just built statement table, each line/statement number in the operation stream is replaced by the absolute address within the stream.

Next a table of the DATA statement locations is created, which concludes the compile phase.

Interpreter

After compilation the interpreter (inter_asm) is invoked. It sets up the data structures and uses a jump table to jump to the actual code blocks that executes the operation tokens in a tight loop (sb_iloop). The code snippets that correspond to the operations have the prefix bo_, so the “+” operation for example is executed by bo_add. This is all done by a fairly complex macro, so if you search the source for bo_add you will only find the code itself but no location from where it is called.

Complex structures like PROCedure calls are split into many different operations, like bo_spcall to setup the call, bo_dospr to actually do it and a lot of operations to set up the parameters (bo_formp amongst others). bo_return handles RETurn statements and also things like END DEFines.

The bug

SBasic crashed in the bo_return code because it a) wanted to clean up the PROCedure parameters and b) wanted to return to the location following the PROCedure call in the operation stream. So what happened? The LRESPRed extension calls sb.inipr (inipr_asm) to link in its new commands. This just results in an extension of the name table, which in itself is not a problem and which made me really wonder where things go wrong. It took me a long time to see that these three little lines cause all the ruckus:

        tas     sb_edt(a6)               ; edited! to redo name types
        sf      sb_cont(a6)              ; do not continue
        move.w  #sb.nact,sb_actn(a6)     ; but no action

The LRESPR function that is loading and executing the extension is itself called in sb_icall, which is called from bo_docpr. This checks the sb_cont flag and returns to sb_istop if not set anymore. As the name suggests this stops the interpretation of the program and returns all the way up to the main SBasic loop. The loop checks which action is to be done, which is sb.nact (no action) and then it COMPILES THE PROGRAM AGAIN! This was a bit surprising at first but if you think about it it’s clear that this needs to be done because we’ve just loaded an extension with new SBasic procedures and functions and the programmer might like to start using those now and they weren’t known when we last compiled the program! But now we’re in the middle of a procedure, how can we just continue here? Enter the “return stack”.

Return stack

As the name implies, the stack holds all data necessary to facilitate returns from PROCedures, FuNctions and GO SUBs. Mainly it holds the return addresses in the operation stream and more data pertaining to the parameters. These are absolute addresses… which is usually not a problem… unless we recompile the program during execution and it so happens that the whole instruction stream data block moves! 😮

First fix

What do we always do in SBasic if a block can move? Correct, we just make all pointers relative to the base. Actually understanding the code a degree to find all those pointers is a wholly different matter, though. And in the end it was all in vain, this did fix most of the crashes but not all, because not only the block as a whole can move but also the operation boundaries within the block, so even relative addresses were not good enough. And as I’m not happy when something only works 50, 80 or even 99% of the time this meant going back to the drawing board.

Final fix

The final code is curiously both more complex and less invasive at the same time: before the program is re-compiled after the LRESPR the return stack entries are now translated from absolute addresses into Line/Statement numbers (using the previously mentioned statement table). The Line numbers are invariant to the compilation process, so after the compilation they are again translated into absolute addresses which always give the correct result, no matter how the compilation changed the operation stream. So the new code should have zero performance and stability implications for ordinary executions and is only active when you LRESPR things. And neither Wolfgang nor I managed to crash it anymore, yay!

The end

This, quite frankly, was a lot of work for such an obscure bug. Why did I do it? One reason is that I’ve been suffering under the bug for a decade without even realising it: when I was toying around with ProWesS I always loaded it conditionally using a PROCedure, which sometimes crashed and I could never explain why and just assumed ProWesS itself was the culprit… the other reason is that stress levels at my real job are currently very high and these puzzles are actually somewhat relaxing sometimes.

No matter the reason, SMSQ/E 3.31 is out and you can enjoy your crash free BOOTs and whatnot from now on. Have fun!