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Weekwander

Oct 5th, 2024
by Jeff Duntemann.
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I spent a week in Chicago (or started out there) to gather with old friends, some from grade school, some from high school, and one (my friend and Best Man Art) from Kindergarten. I rented a smallish car (a 2024 Corolla Cross, which I had not heard of before) and Art and I forged west to the town of Galerna, in northern Illinois on the Mississippi River. My old friend Rich (whom I met in third grade, as best I recall) has a place there. For three days we drank wine and ate cheeseburgers, played whiffle golf around Rich’s substantial house, watched the stars from his front porch, and laughed our asses off over old stories of school, The Fox Patrol in Boy Scouts, college parties, the Resurrection Hospital dish room, where most of us worked at one time or another, and much else. Rich took us all (there were six present) on a pontoon boat tour of Galena Lake near his house.

I’ve read in many places that bonding with friends is one of the best ways to keep your brain cells alive and functional, and now that we were all in our 70s, I took great comfort in that. Rich has been holding these gatherings for almost 20 years, and (especially in the last 10 or 12 years) the group has shrunk from 15 or more down to seven or eight, of which a couple couldn’t make it this year. Each time one of the group passes on, we plant a tree on the slopes of the hill near Rich’s house in their honor.

After we returned from Galena, I visited with my father’s youngest cousin Mary Ellen, and her daughter Mary Kate. They’ve been friends for a very long time, and both helped me piece together the Duntemann family tree back in the ‘90s. We laughed and remembered old times, like the freshman ROTC Military Ball that I was required to attend, and did, with my cousin Mary Kate on my arm. She was a beautiful girl (still is, in my eyes) and I hope it wasn’t a sin that I quietly neglected to tell anybody that she was my cousin, including all my nerdy friends who attended the ball alone.

Honor is good. I honor all my friends, alive or dead, as I will as long as I’m here in God’s beautiful and extravagant creation—and maybe beyond.

֎

The day I flew back from Chicago (October 2nd) was our 48th wedding anniversary, and Carol and I celebrated and had a nice dinner out together. Again, friendship underlies our relationship, and has always done so, across our 48 years as spouses and 55 years as best friends. Friendship, as I’ve said many times here and elsewhere, is the cornerstone of the human spirit, the anchor to which all other positive forces that act upon relationships are anchored. Marriage works—if you work at it, as Carol and have always done and will always do.

֎

Some time back I was threading my way through parts of the Scottsdale-Thunderbird shopping plaza where I don’t often go, and saw that the restaurant Casa Greeka was evidently closed. My guess is that COVID did them in, as it did in so much else. Their theme was Mexican-Greek fusion. I never ate there, but I did wonder what people of Greek heritage thought of the name. The proper name would (perhaps; I’m not Greek) be Casa Greco.

But it got me thinking about food fusion for a bit. How about this: A restaurant specializing in Irish-Hawaiian fusion, called Lovely Houlihan’s. Don’t fret if you don’t get the joke. It’s for old people.

֎

Yes, it’s true: I’m finally closing in on the last bits of my new novel, The Everything Machine. It’s the cornerstone Drumlins story, and will reveal (most of) the mystery behind the thingmakers and the alien minds that created them. If you must genre-tag the novel, I call it a Space Western, with a side order of airships and a whiff of Dieselpunk. Should come in between 120,000 and 125,000 words, which is 25,000 words shorter than The Cunning Blood. After I get that published, I’m going to work on nonfiction for a bit, starting perhaps with a Square One introduction to Windows programming with Lazarus/FreePascal, drawing on my parts of The Delphi 2 Explorer. I already have 7,000 words on that book, which I set aside in 2021 when I began The Everything Machine. There’s a lot to cover, especially for a beginner audience, and I don’t know how long it will be. I won’t know (as usual) until I finish it. Wish me luck.

Lazarus 3.0 Has Arrived!

Dec 22nd, 2023
by Jeff Duntemann.
5 comments

For all you Pascal programmers among my readers: Lazarus 3.0 is out, and available for free download. Here’s the announcement. I’ve already installed it on Win10 and will install it on Linux when time becomes available. (I’m still struggling to write the trademark Jeff Duntemann mayhem-filled action climax of my current WIP: The Everything Machine, the first full-length drumlins novel.)

Delphi now costs over $1000. If I’m going to teach Pascal, I can’t use Delphi, love it though I may–and do. Lazarus is pretty much Delphi’s peer, though it doesn’t…quite…have the third-party component aftermarket that Delphi has. Doesn’t matter. The fundamental principles of OOP and event-driven programming are the same.

For newcomers: Lazarus is a superb IDE and drag-‘n-drop GUI builder conceived as a Delphi competitor, though open-source and thus free of charge. It uses FreePascal 3.2.2 as its compiler. FreePascal understands Delphi’s additions to the Pascal programming language, and will also compile ancient Turbo Pascal programs. FreePascal is part of the Lazarus package and is installed when you install Lazarus. I have fragments of a book on Lazarus that I will return to at some point. But if you know Delphi, well, there’s not a lot more to learn. You’ll feel right at home.

Go get it. I’ve done a lot of work in Lazarus. It’s mature. It works. It can create wonderful GUI apps. And it’s free. What more do you want?

No More Assembly Required

Feb 22nd, 2023
by Jeff Duntemann.
14 comments

In other words: It’s done. Well, at least the hardest part (for me) is done: Yesterday I uploaded the last odd bits of x64 Assembly Language Step by Step, Fourth Edition to the publisher’s cloud. Now comes the work that I don’t have to do: copy edits, tech edits, layout, proofing. I will have some odds and ends to deal with down the road a ways, like looking at the proofs, building the listings archive, and rewriting my assembly book web page to reflect the new edition.

The publisher hired the estimable David Stafford to do tech edits, which is quite an honor. I’ve known David since the early PC Techniques days, and that guy knows his stuff with a capital-K. If there are booboos, bugs, or dryer lint in that thing, he’ll spot it. (Dryer lint we may leave for the production service.)

I’ve been working on this project since mid-April 2022. This is the fourth edition of the book from John WIley, and the fifth edition overall. The very first edition came from Scott, Foresman at the end of 1989, and was part of a short-lived assembly language series that I acquired and edited for them on contract back in the very late ‘80s. Its original title was Assembly Language from Square One. We were just getting out of second gear in 1990 when Scott Foresman was sold to Harper Collins. Toward the end of 1990, Harper Collins put the Scott Foresman trade book line out of print. I got the rights back in 1991.

I turned around and took the book to John Wiley, who bought it on the spot. I rewrote and expanded the book, which appeared from Wiley in 1992. The title had to change when I took it to Wiley to avoid mixups on retail channel returns, so the book became Assembly Language Step-by-Step. That’s not a bad title, in fact, since the whole point of the book was to do a methodical, patient introduction for people just getting started in computing. The 1992 edition was all-DOS, as you might imagine. In 1999 Wiley asked me to do an update that included both DOS and 32-bit Linux. I retained nearly all of what had been in the first Wiley edition, and added another 200 pages for 32-bit concepts and Linux. It was published in 2000.

That book sold extremely well for its nine-year life. In 2008 Wiley asked me for a new edition devoted entirely to Linux. DOS was almost extinct by then, so it was a good move. With only one tail to wag I was able to go into a great deal more detail about Linux and 32-bit protected-mode programming generally. It was a big job that took me seven or eight months, but the book appeared in 2009, at 610 pages.

As the teens drew toward the 20s and 64-bit Intel/AMD CPUs went mainstream, I enquired about a 64-bit edition every so often. In each case, my acquisitions editor basically said, “Don’t call us. We’ll call you.” So I stopped asking, and the 2009 edition kept on selling.

The call came in early April 2022. My old acquisitions editor had retired, and the new one was very much on board with an x64 rewrite. He asked me how long it would take. By then I was 69, and asked, How about a year? He said, Sure.

And that’s almost what it took, whew.

I don’t exactly when we’ll have books. Summer, I’m guessing; maybe late summer. It’s hard to know in this business. I’ve already been asked if I’m ever going to do a 128-bit version. Well, we need 128-bit CPUs first, and in truth I don’t see them on the horizon. We needed 64 bits for the address space way more than the register width. Since the AVX-512 math subsystem on nearly all modern Intel/AMD CPUs already has 512-bit registers, we don’t need the register width, and since 264 is 1.84 x 1019, we’ve already got all the address space we will ever need.  Without 128-bit Intel/AMD CPUs, my guess is that the fourth edition of the book will be the last, and it could well be around long after I go on to other realms.

If I’m going to do any large-scale programming tutorials going forward, it’ll be about the Lazarus IDE and GUI builder. But at least for the coming year, if I write anything at all I’m going to write SF.

But I think you knew that.

A libc Mystery

Nov 25th, 2022
by Jeff Duntemann.
19 comments

As most of you know by now, I’m hard at work on the x64 edition of my assembly book, to be called X64 Assembly Language Step By Step. I’m working on the chapter where I discuss calling functions in libc from assembly language. The 2009 edition of the book was pure 32-bit x86. Parameters were passed to libc functions mostly by pushing them on the stack, which required cleaning up the stack after each call, etc.

Calling conventions in x64 are radically different. The first six parameters to any function are passed in registers. (More than six and you have to start pushing them on the stack.) The first parameter goes in RDI, the second in RSI, the third in RDX, and so on. When a function returns a single value, that value is passed back in RAX. This allows a lot more to be done without fooling with the stack.

Below is a short example program that makes four calls to libc functions: Two calls to puts(), a call to time, and a call to ctime. Here’s the makefile for the program:

showtime: showtime.o
        gcc showtime.o -o showtime -no-pie
showtime.o: showtime.asm 
        nasm -f elf64 -g -F dwarf showtime.asm -l showtime.lst

I’ve used this makefile for other example programs that call libc functions, and they all work. So take a look:

section .data
        timemsg db    "The timestamp is: ",0
        timebuf db    28,0   ; not useed yet
        time1   dq    0      ; time_t stored here.

section .bss

section .text

extern  time
extern  ctime
extern  puts
global  main

main:
        push rbp            ; Prolog    
        mov rbp,rsp

        mov rdi,timemsg     ; Put address of message in rdi
        call puts           ; call libc function puts
               
        xor rax,rax         ; Zero rax
        call time           ; time returns time_t value in rax        
        mov [time1],rax     ; Save time_t value to var time1
        
        mov rdi,time1       ; Copy pointer to time_t value to rdi
        call ctime          ; Returns ptr to the date string in rax

        mov rdi,rax         ; Copy pointer to string into rdi
        call puts           ; Print ctime's output string
        
        mov rsp,rbp         ; Epilog
        pop rbp
        
        ret                 ; Return from main()

Not much to it. There are four sections, not counting the prolog and epilog: The program prints an intro message using puts, then fetches the current time in time_t format, then uses ctime to convert the time_t value to the canonical human-readable format, and finally displays the date string. All done.

So what’s the problem? When the program hits the second puts call, it hangs, and I have to hit ctrl-z to break out of it. That’s peculiar enough, given how many times I’ve successfully used puts, time, and ctime in short examples.

The program assembles and links without problems, using the makefile shown above the program itself. I’ve traced it in a debugger, and all the parameters passed into the functions and their return values are as they should be. Even in a debugger, when the code calls the second instance of puts, it hangs.

Ok. Now here’s the really weird part: If you comment out one of the two puts calls (it doesn’t matter which one) the program doesn’t hang. One of the lines of text isn’t displayed but the calls to time and ctime work normally.

I’ve googled the crap out of this problem and haven’t come up with anything useful. My guess is that there’s some stack shenanigans somewhere, but all the register values look fine in the debugger, and the pointer passed back in rax by ctime does indeed point to the canonical null-terminated text string. The prolog creates the stack frame, and the epilog destroys it. My code doesn’t push anything between the prolog and epilog. All it does is make four calls into libc. It can successfully make three calls into libc…but not four.

Do you have to clean up the stack somehow after a plain vanilla x64 call into libc? That seems unlikely. And if so, why doesn’t the problem happen when the other three calls take place?

Hello, wall. Anybody got any suggestions?

SASM Crashes on “Section” in a Comment

Aug 28th, 2022
by Jeff Duntemann.
4 comments

As most of you know, I’m grinding along on the fourth edition of my book Assembly Language Step By Step, updated to cover x64. I’m using the SASM IDE for the example code because it provides seamless visual debugging using a front-end to gdb. Back in 2009 I created the third edition, and incorporated the Insight debugger front end for visual debugging. A month or so after the book appeared, Insight vanished from the Linux world. I tried a lot of debuggers and editors before I discovered SASM. It’s treated me very well.

Until today.

Now, I’ve been programming since 1970, in a lot of languages, on a lot of platforms, and I’ve made a lot of mistakes. Finding those mistakes is what debugging is about. Today, I was working on a short example program for the book. When I finished it, I clicked the Build button. It built as it should. I needed to single-step it to verify something about local labels, but when I clicked the debug button, SASM crashed. As Shakespeare would have put it, SASM died and gave no sign. The whole IDE just vanished. I tried it again. Same thing. I rebooted Linux. Same thing.

Puzzled doesn’t quite capture it. I loaded another example program from the book. It built and debugged without any trouble. I loaded example after example, and they all worked perfectly. Then I copied the source from the malfunctioning example into a file called crashtest.asm, and began cutting things out of it. I got it down to a start label and a SYSCALL to the exit function. Still blew SASM away.

Most of what was left was comments. I did a ctrl-X to cut the comment header onto the clipboard. Save, build, debug–and it worked perfectly.No crash, no errors, no problemo.

Soooooooo…….something in a comment header crashed the IDE? That would be a new one. So I dropped the comment header back into the file from the clipboard and started cutting out lines, one by one. I narrowed it down to one comment line, properly begun with a semicolon and containing no weird characters. The line that crashed SASM was this:

;         .bss sections.

I cut out the spaces and the period. No change. I cut out “.bss”. No change. I was left with the word “sections.” On a hunch, I lopped off the “s”. No change. Then I lopped off the “n”. Suddenly, it all worked.

SASM was crashing on a comment containing the word “section.” I verified by deleting the line entirely and typing it in again. Crash!

I stared at the damned thing for a long time. I loaded a couple of my other examples, and dropped the offending comment header into them. No problems. Twenty minutes later, I noticed something: In crashtest.asm, the fragment of comment header text was below the three section markers:

section.bss
section.data
section.text

; section

Now, in my other examples, the ones that didn’t crash, the comment header was above the three section markers. So I went back to crashtest.asm, and moved the comment header to the very beginning of the file, above the section markers. Suddenly everything worked. No crashes.

WTF? I assembled the offending crashtest binary from the command line without trouble. I loaded it into gdb from the command line and messed with it. No trouble.

I wrote this entry not for answers so much as to provide a report that other SASM users can find in search engines. There are things about SASM that aren’t ideal. Sure. But I’ve never seen it crash before. I’ll see if I can send the crashtest.asm to the people who created SASM. I’m sure it’s just a bug. But it’s the weirdest damfool bug I’ve uncovered in a whole lot of years!

In Pursuit of x64

May 31st, 2022
by Jeff Duntemann.
10 comments

You may be wondering where I am, given that I haven’t posted a Contra entry for over a month. I didn’t want May to conclude with zero entries posted, so I figured I’d take a break here and get you up to speed.

Here’s the deal: My publisher has asked for a Fourth Edition of Assembly Language Step-By-Step. It’s been thirteen years since the Third Edition came out, so it’s well past time. The idea here is to bring the book up to date on the x64 architecture. In fact, so that no one will mistake what’s going on, the title of the new edition will be x64 Assembly Language Step-By-Step, Fourth Edition. Whether they keep the “x” in lowercase remains to be seen.

So I’m off and editing, writing new code and checking every code snippet in a SASM sandbox, and making sure that I don’t forget and talk about EAX and other 32-bits-and-down entities without good reason. (There are good reasons. Even AH and AL are still with us and used for certain things.) Make no mistake: This is going to be a lot of work. The Third Edition is 600 pages long, which isn’t the longest book I’ve ever written (that honor belongs to Borland Pascal 7 From Square One, at 810 pages) but it’s right up there.

My great fear has been the possibility of needing to add a lot of new material that would make the book even longer, but in truth, that won’t be a huge problem. Here’s why: Some things that I spent a lot of pages on can be cut way back. Good example: In 32-bit Linux, system calls are made through the INT 80H call gate. In the Third Edition I went into considerable detail about how software interrupts work in a general sense. Now, x64 Linux uses a new x64 instruction, SYSCALL, to make calls into the OS. I’m not completely sure, but I don’t think it’s possible to use software interrupts at all in userspace programming anymore. I do have to explain SYSCALL, but there’s just not as much there there, and it won’t take nearly as many words and diagrams.

Oh, and of course, segments are pretty much a thing of the past. Segment management (such that it is) belongs to the OS now, and for userspace programming, at least, you can forget about them. I’m leaving a little description of the old segment/offset memory model for historical context, but not nearly as much as in previous editions.

I also dumped the Game of Big Bux, which doesn’t pull its weight in the explanation department, and isn’t nearly as funny now as it was in 1990. But have faith: The Martians are still with us.

My guess is that from a page count standpoint, it will pretty much be a wash.

It’s going to take me awhile. I don’t know how long, in truth. Especially since I am going to try to keep my fiction output from drying up completely. The book will slow me down, but (for a change) the publisher is not in a huge hurry and I think they’ll give me the time I need. I have 56,000 words down on The Everything Machine, and don’t intend to put it on ice for months and months. I’m not sure how well that’s going to work. We’ll see.

Odd Lots

Apr 27th, 2022
by Jeff Duntemann.
17 comments
  • Pertinent to my last two entries here: City Journal proposes what I proposed two years ago: To reduce the toxicity of social media, slow it down. What they propose is not exponential delays of replies and retweets to replies and retweets until those delays extend fifteen minutes or more. Like a nuclear reactor control rod, that would slow the explosion down until the hotheads cooled off or got bored and went elsewhere. Instead, they suggest Twitter insist on a minimum of 280 characters to posts. That might help some, but if the clue is to slow down viral posts, eliminate the middleman and just slow down responses until “viral” becomes so slow that further response simply stops.
  • A statistical study of mask use vs. COVID-19 outcomes found no correlation between mask use and better outcomes, but actually discovered some small correlation between mask use and worse outcomes. Tough read, but bull through it.
  • While not as systematic as the above study, an article on City Journal drives another nail in the coffin of “masks as infection prevention.” Graph the infection rates in states with mask mandates and states with no mask mandates and they come out…almost exactly the same.
  • Our Sun is getting rowdy, and getting rowdier earlier than expected. Cycle 25 is starting out with a bang. Recent cycles have been relatively peaceful, and nobody is suggesting that Cycle 25 will be anything close to the Cycle 19 peak (1957-58) which was the most active sunspot max in instrumental history. What Cycle 25 may turn out to be is average, which mean 20 meters may start to become a lot more fun than it has been in recent (slow) years.
  • And this leads to another question I’ve seen little discussion on: To what extent are damaging solar storms correlated to sunspot peaks? The huge solar storm of 1921 took place closer to the sunspot minimum than the maximum. The legendary Carrington event of 1859 took place during the fairly weak Cycle 10. As best I can tell, it’s about individual sunspots, and not the general state of the Sun at any point in time.
  • NASA’s Perseverence Mars rover caught a solar eclipse, when Phobos crossed the disk of the Sun as seen from Perseverence. The video of the eclipse was sped up, but it really is a startling image, especially if you know a little about Phobos, which is decidedly non-spherical.
  • I found this very cool: An online, Web-based x86/x64 assembler/disassembler. Although intended for computer security pros, I found it a lot of fun and it may turn out to be useful here and there as I begin to revise my assembly book for the fourth time.
  • Skipping sleep can lead to putting on belly fat, which is absolutely the worst place to have it. Get all the sleep you can, duh. Sleep is not optional.
  • How many stars are there in the observable universe? It’s a far trickier and sublter calculation than you might think. But the final number looked familiar to me, and might look familiar to people who do low-level programming.

Problems with SASM on Linux Mint

Apr 6th, 2022
by Jeff Duntemann.
19 comments

I’m scoping out a fourth edition of my book, Assembly Language Step by Step. I got wind of a simple FOSS utility that could be enormously useful in that effort: SASM (SimpleASM), which is an IDE created specifically for assembly-language work. It’s almost ideal for what I need: Simple, graphical, with a surprisingly sophisticated text editor and a graphical interface to GDB. It works with NASM, my assembler of choice. I want to use it as the example code IDE for the book. I installed it without effort on Windows, which is why I decided to use it. But I want to use it on Linux.

Alas, I’ve been unable to get it to install and run on Linux Mint 19 (Tara) using the Cinnamon desktop.

I’ve installed a lot of things on Linux Mint, all of them in the form of Debian packages. (.deb files.) I downloaded the SASM .deb file for Mint 19, and followed instructions found on the Web. There is a problem with dependencies that I just don’t understand.

I got it installed once but it wouldn’t run. I uninstalled it, and then it refused to reinstall.

Keep in mind that I am not a ‘leet Linux hacker. I’m a teacher, and most of what I teach is computing and programming for newcomers. The problem may be obvious to Linux experts but not to me. Most of the software I’ve installed on Mint came from repositories. SASM is a .deb download.

So. Does anybody else use it? If you’ve got Mint on a partition somewhere, could you try downloading it and installing it? I need to know if the problem is on my side of the screen or the other side.

Thanks in advance for any advice you might offer.

Odd Lots

Apr 4th, 2022
by Jeff Duntemann.
23 comments
  • I got caught in an April Fools hoax that (as my mother would say) sounded too true to be funny: That Tesla canceled all plans to produce its Cybertruck. (Read the last sentence, as I failed to do.) I like Musk; he has guts and supports space tech. About his Cybertruck concept, um…no. It looks like an origami, or else something that escaped from a third-shelf video game. The world would go on without it, and he might use the money to do something even cooler, whatever that might be.
  • Oh, and speaking of Elon Musk: He just bought almost 10% of Twitter, to the tune of about $3B. He is now the biggest outside shareholder. This is not a hoax, and I wonder if it’s only the beginning. Twitter is famous for suspending people without explaining what they did wrong, sometimes for things that seem ridiculously innocuous. A major shareholder could put pressure on Twitter’s management from the inside to cut out that kind of crap. It’s been done elsewhere. And boy, if anybody can do it, he can.
  • Nuclear energy has the highest capacity factor of any form of energy, meaning the highest percentage of time that energy producers spend actually producing energy. I knew that from my readings on the topic. What shocked me is that there is in fact an Office of Nuclear Energy under the DOE. I’m glad they exist, but boy, they hide well.
  • The Register (“Biting the hand that feeds IT”) published a fascinating article about how C has slowly evolved into an Interface Definition Language (IDL). C was never intended to do that, and actually does a pretty shitty job of it. Ok, I’m not a software engineer, but the way to build a new operating system is to define the IDL first, and work backwards from there. C is now 50 years old, sheesh. It’s time to start again, and start fresh, using a language (like Rust) that actually supports some of the security features (like memory protection and safe concurrency) that C lacks. This is not Pascal sour grapes. I’m studying Rust, even though I may never develop anything using it. Somehow, it just smells like the future.
  • Drinking wine with food (as I almost always do) may reduce your chances of developing type 2 diabetes. It’s not taken up in the article, but I have this weird hunch that sweet wines weren’t part of the study. Residual sugar is a real thing, and I’m drinking way less of it than I did 20 years ago.
  • People have been getting in fistfights over this for most of a century, but establishing Standard Time year-round may be better than year-round Daylight Savings Time. I’m mostly neutral on the issue. Arizona is on permanent DST and we like it fine. The problems really occur at high latitudes, where there isn’t much daylight in winter to begin with, so shifting it an hour in either direction doesn’t actually help much.
  • There is Macaroni and Cheese Ice Cream. From Kraft. Really. I wouldn’t lie to you. In fact, I doubt I would even imagine it, and I can imagine a lot.
  • Optimists live longer than pessimists–especially older optimists. Dodging enough slings and arrows of outrageous fortune somehow just makes the whole world look brighter, I guess.
  • Finally, some stats suggesting that our hyperpartisan hatefest online has pushed a lot of people out of political parties into the independent zone–where I’ve been most of my post-college life. 42% of Americans are political independents, compared to 29% who are Democrats and 27% who are Republicans. I’m on Twitter, but I don’t post meanness and (as much as possible) don’t read it. And if Mr. Musk has his way with them, I may be able to post links to ivermectin research without getting banned.

Odd Lots

Jan 26th, 2022
by Jeff Duntemann.
6 comments
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