Questions tagged [programming]

For questions about programming languages and constructs. For questions about specific languages please check for language-specific tags first, and use those instead.

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3
votes
2answers
180 views

Is there a way to blank out a portion of a screen on Commdore C64?

I would like to blank out a couple of lines between two given rasterlines. Above that I'm planning to have a scrolling background and sprites, below that is a textual info area. I'm thinking of a ...
16
votes
4answers
909 views

Toolchain and workflow to build CP/M

Building my own version of CP/M has always been a fascinating to-do project. Problem is that it seems that the source code is not in regular assembler, but some kind of macro-assembler like language ...
90
votes
8answers
27k views

Why would a NES game use an undocumented 1-byte or 2-byte NOP in production?

Reading the NESdev wiki page on CPU unofficial opcodes, I see a few games use an undocumented 2-byte NOP instuction in production: Puzznic, F-117A Stealth Fighter, and Infiltrator use $89 #i. Beauty ...
2
votes
1answer
98 views

Are there open source Java libraries for reading DSK and EDSK disk image files as used by Amstrad and Spectrum +3 emulators?

I've been working on some modules for the Ghidra reverse engineering tool. Ghidra is written in Java, which I'd always avoided when I was more actively programming so this is an opportunity to learn ...
4
votes
1answer
229 views

Back in the day, were games coded to run better with more (not faster) RAM? [closed]

Let's say the year is 1999 or something like that. I have a PC with 400 MHz, no graphics accelerator and 64 MB RAM, and try to run some Need for Speed game or something. I notice that it goes laggy. ...
12
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2answers
653 views

Did the Commodore 128's Z80 CPU also have full access to the machine's custom hardware?

The C128 was a C64 with an extra CPU as well as extra memory. But the second CPU was a Zilog Z80 while the primary was the usual Commodore CPU, a MOS 6502. The Z80 was there so that CP/M software ...
17
votes
1answer
458 views

Was the IBM S/360 Responsible for Popularizating the 'A'-to-'F' Notation in Hexadecimal Numbers?

In the early history of computing before the mid-1960s, there wasn't an universal, de-facto standard for the written representation of a hexadecimal number, different computer systems used their own ...
2
votes
1answer
47 views

What is the layout of the directory track on a TRS-80 Model I/Model III disk?

I've decided to add support for some more classic Z80 computers I used to use to my Ghidra modules, and the first Z80 systems I used were the TRS-80 model I and model III. I've found documentation ...
7
votes
2answers
770 views

How can I programmatically determine whether an Apple II .dsk disk image is a DOS .do image or a ProDOS .po image?

I'm interested in working with the most common Apple II disk image file format, .dsk. (I only programmed these machines briefly in Basic around 1979-81 and have not been in the emulator scene, so I'm ...
27
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2answers
3k views

Apple II: Applesoft BASIC memory management

I am trying to write an Applesoft / floating point BASIC program using high resolution graphics and some assembly language code. My BASIC program is quite large, and after running the program for a ...
1
vote
3answers
228 views

Program memory limit [closed]

In the past, a program could only use a specific part of the computer's memory. If multiple instances of the same program were open, they shared this one memory block. To prevent this, some developers ...
27
votes
2answers
9k views

What is this programming language having PROC, DCL, LABEL keywords?

A 1980 paper called "Register Allocation via Coloring" contains something that looks like source code: P: PROC(MODE); DCL MODE BIT(1), (A1,A2,A3,A4,A5,A6,A7,A8,A9,A10, B1,B2,B3,...
9
votes
2answers
1k views

What was the first preprocessor for a programming language?

A preprocessor is a tool that takes source code as input and outputs a modified version of it for input to a downstream tool, such as a compiler or interpreter. Preprocessors can be used to implement ...
23
votes
7answers
4k views

Was it possible programmatically to manipulate the volume as well as the pitch on computers with no sound chip?

On early versions of many 8-bit computers like the Apple II, Spectrum, and even the IBM PC, there was no sound hardware other than the simple "beeper". Programmers made sound by hitting a hardware ...
9
votes
1answer
381 views

Can you program an arcade game and have MAME or another emu run it?

I know Mame works with drivers for each game or hardware, and it checks for specific ROMs, and I guess it might check also for some checksum to verify the ROMs integrity. Is there some way you could ...
31
votes
3answers
3k views

How did Elite do vertex transformation?

In 3D graphics, vertex transformation is the process of converting x,y,z coordinates in 3D space, to x,y coordinates on the screen. According to https://www.khronos.org/opengl/wiki/...
5
votes
2answers
400 views

How did Microsoft get away with JScript? [closed]

How exactly did Microsoft reverse engineer Brendan Eich's JavaScript, call it something else and not get a massive lawsuit in the aftermath? I understand this was a long time ago but I still wonder ...
18
votes
9answers
2k views

How were bugs reported for compilers that were shipped on floppy disks?

Take the Microsoft C 1.0 compiler for example. It shipped on multiple 5.25" 360K disks, and when it ran on machines without internal hard disk, so users had to switch floppies between the editor, ...
13
votes
1answer
453 views

Did Babbage's Analytical Engine lack indirect addressing?

As I understand it the analytical engine could only refer to memory by variable cards that had the explicit address printed on them, see https://www.fourmilab.ch/babbage/cards.html. For instance the ...
23
votes
8answers
2k views

What implementations of BASIC had a robust flood fill operator?

When I learned BASIC on Elektronika BK, I got fascinated with the flood fill (PAINT) operator: how does it know to get to all nooks and crannies of the shape to fill? I've devised an algorithm, tried ...
20
votes
3answers
2k views

How were the 70's and 80's coin-op programmed?

How were the 70's and 80's coin-op programmed? What tools did a programmer use? Nowadays a programmer can use a PC, an IDE to program, test, use breakpoint... but in the 80s? How could a programmer ...
1
vote
5answers
839 views

What was the first introduction of callback concept of programming?

Although I seriously code with computer languages in general since 2010 and as an amateur programmer with programming languages in particular since 2015 (primarily Bash and JavaScript imperative ...
8
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4answers
1k views

What was the earliest microcomputer Logo language implementation?

Wikipedia has a long list of Logo implementations, but I'd like to know what the earliest implementation is on a microcomputer, or, more likely, what are the earliest ones if there isn't one with ...
-5
votes
1answer
169 views

What is the maximum 64 bit integer (number) value? [closed]

I already know that the maximum integers for ranges higher than 24-bit (16 777 216) will very likely exceed 1 000 000 000, so, what is the maximum 64 bit integer? It is larger than 10 bilion?
10
votes
1answer
1k views

What was the first programming language to have 'printf'?

I'm curious as to which language was the first to literally have a formatted text output procedure called 'printf'. A trivial question, sure, but I was prompted to ask by a recent question on ZSPL. ...
11
votes
1answer
479 views

Why didn't Wozniak's interrupts work on the Apple I monitor program?

In his autobiography, Steve Wozniak recounts[1] his difficulty getting interrupts working on the 6502 microprocessor: The next step was to debug the 256-byte monitor program on the PROMs. I spent ...
7
votes
2answers
848 views

Were any DOS games (or software) known to use VBE/AF?

Were there any MS-DOS games or graphics software that were known to take advantage of VESA BIOS Extensions/Accelerator Functions (VBE/AF)? some of the functions defined in the standard are ... Bit ...
3
votes
1answer
346 views

How to read disk files using CBM specific functions in cc65 with proper error checking

TL:DR What is the reason my kernel_read() function ignoring file errors? I'm trying to understand how to work with files in cc65 using CBM specific functions. My target is Commodore 64 with 1541 ...
5
votes
3answers
460 views

How to use HGR2 (or HGR) on an Apple II

I am a big fan of the TV show lost, and I was trying to make the Dharma Initiative logo. But at certain point I couldn't add new lines of code and the final part of the logo was cut off. I tried to ...
2
votes
8answers
1k views

Are there any old and nowadays active Operating Systems which has only BASIC Programming Language?

Some old Operating Systems I hear have only BASIC Programming Language. Are there any active and old operating systems which includes only BASIC Programming Language?
2
votes
1answer
551 views

What programming languages appeared in 1961?

I'm trying to get Programming Languages Through The Years over on the Code Golf site going again. The Wikipedia article that the challenge has been working from only lists COMIT for 1961, and calling ...
16
votes
2answers
1k views

What was the first language with regexes?

According to Wikipedia, Regular Expressions (AKA regexes) have only been around since 1956: Regular expressions originated in 1956, when mathematician Stephen Cole Kleene described regular ...
2
votes
2answers
341 views

emulator library that allows to partially emulate old games [closed]

EDIT: previously I added a lot of examples to this questions. I removed the examples, because the question was voted to be "too broad", so I put more emphasis on the question again. Question: Is ...
13
votes
3answers
1k views

Pattern matching, which language first had it

Which programming language was the first to use pattern match? The oldest ones I know are: Prolog 1972 ML 1973 Are there languages older that have pattern matching? Edit: By pattern matching I ...
5
votes
2answers
373 views

How was dataflow analysis performed before SSA?

If we look at something like LLVM or the GNU Compiler Collection, Dalvik and many others, their intermediate representation (IR) uses SSA (Static Single Assignment form), as part of their Data-Flow ...
69
votes
5answers
12k views

Why wasn't ASCII designed with a contiguous alphanumeric character order?

Anyone who has dealt with strings at a low level (e.g., writing a parser in C), knows that doing so tends to involve frequent checks of—either manually, or through isalpha(), isalnum(), etc—whether a ...
38
votes
8answers
7k views

What was the point of separating stdout and stderr?

I occasionally need to work with console commands and 100% of the time I want to redirect my output to a file I fail to redirect stderr as well as stdout the first time. I can't think of a single ...
8
votes
2answers
679 views

Is there data for programming language popularity pre year 2000?

Besides the TIOBE Index, which ranks programming language popularity by search engine hits and seems to have data reaching back to the year 2001, are there other sources with some form of measure for ...
10
votes
2answers
643 views

Why are my VGA vram to vram copies so slow?

I'm doing some mode x programming and I noticed that my vram to vram copies are much slower than I expected. My copying method was described by Michael Abrash in his Graphics Programming Black Book ...
54
votes
6answers
12k views

How did old MS-DOS games utilize various graphic cards?

Nowadays each graphic card has some driver in operating system that translates some (typically) standard API such as OpenGL, so that programmers use some standardized API code to tell graphics cards ...
3
votes
3answers
2k views

Reading both keyboard and joystick with non-KERNAL code on C64

I'm implementing non-KERNAL joystick and keyboard controls for my Commodore 64 game. I used to use the KERNAL SCNKEY routine earlier to read keyboard and it worked well with my joystick port 2 code. ...
14
votes
9answers
2k views

What is the most rudimentary input method a platform has ever been programmed in?

A while ago I did read on the web a page whose topic was more or less: Real men write [insert lowest level language here] (a similar page would be this Reddit thread) If we quickly tour some of the ...
17
votes
3answers
2k views

Is there a way to get a compiler for the original B programming language?

I am learning about the original B programming language, but I don't have a compiler. Is there an emulator for an old computer that can run an old operating system that have a compiler for the ...
7
votes
3answers
539 views

Did the BCPL programming language support floats?

Did the BCPL programming language support floating point? If not, then how did programmers use it to add two floating point numbers?
7
votes
1answer
290 views

How to add an “int” to a “float” in the B programming language?

C has data types, so if you add an int to a float, for example: int i = 1; float f = 2.5; float r = i + f; The C compiler will know that it should generate machine instructions that adds an int to a ...
22
votes
10answers
5k views

Was Objective-C really a hindrance to Apple software development? [closed]

I have heard stories from some of the greybeards I have met on the Internet that Objective-C was by all accounts a nightmare to work with. Was that just a thing about all the low-level languages of ...
14
votes
3answers
5k views

MSX Assembly/Basic programming documentation

I'd like to try to create software (and maybe simple games) for the MSX standard. I know I have two ways to do so, either I use MSX Basic or Z80 assembly. I think that Z80 assembly is more powerful ...
1
vote
2answers
249 views

What was the first language compiler to support subtype polymorphism? [closed]

I'm trying to understand the history of Dependency Injection in compiled languages, as an intentional feature of the language. The Wikipedia article on the subject is decidedly Java focused, but I ...
13
votes
3answers
4k views

Native C compiler for Sinclair ZX Spectrum

I am looking for a native C compiler for the Spectrum 128. I would like one which: Has good support for the latest C standard at the time. Is not limited to compiling ridiculously short source code. ...
2
votes
1answer
163 views

Decoding the Workings of the TRS-80 BASIC Game “Escape!”

I've decided to port Chase! to Swift, apparently because I am insane. In any event, I'm trying to collect the various switches in versions from the era. One of these is unique, found here under the ...