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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.

6
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1answer
136 views

PLATO & JS99'er

Has anyone out there managed to load a PLATO PHM 3122 cartridge by Control Data into the JS99'er emulator? That way a user could place all of the PLATO Lesson Disks on a cloud location (e.g., ...
2
votes
3answers
176 views

What was the DOS FAT12 720k floppy raw disk format structure?

I am looking for detailed info on the low-level floppy disk structure of an MSDOS-compatible 720k Double Sided Double Density disk. Stuff like GAP/SYNC patterns, ID and CRC Field structure, standard ...
30
votes
6answers
10k views

Which was the first programming language that had data types?

Machine language (and Assembly language) don't have the concept of data types, so if you want to add an int and a float variables in Assembly, you have to use the appropriate Assembly instruction that ...
3
votes
1answer
158 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 ...
1
vote
1answer
197 views

What don't I understand about this LR35902 code?

The question you are now reading is about a comment on this question, about overflow bugs in some Pokemon game. A comment on that question says: It was Game Freak's first project. They just were ...
1
vote
5answers
368 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?
3
votes
2answers
314 views

EGA style 16 color dithering

I am trying to write a program in C# that will re-create the type of dithering used in many of the old sierra and Lucas arts games. I have looked up many different dithering algorithms and none seem ...
17
votes
2answers
613 views

What's a good way to implement this “splashing water” effect on the C64?

This pillow fighting game set in Venice depicts the two opponents fighting on a wobbly gondola on a canal. It was apparently known as "Pillow Fight" in English and as "Kissenschlacht" in German, and ...
1
vote
1answer
162 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 cc54 using CBM specific functions. My target is Commodore 64 with 1541 ...
38
votes
8answers
6k views

What was the first programming book

I'm curious, what was the first book, about programming for digital computers. I tried to google it, but it led me to multiple results. I'm mostly interested in the language it was about and the ...
6
votes
3answers
575 views

First language designed to support embedding?

Some languages like Python, Lua, and Tcl are designed with the intention that you can easily embed the interpreter into some other native program. For example, many VFX applications like Nuke, Maya, ...
59
votes
7answers
13k views

Where did the popularity of the `i` variable come from?

I have heard that the reason the i variable is used so much is because there was an old computer where each variable could only be a single letter and that reserved the variables a through h as ...
4
votes
1answer
430 views

Where can I find macrofun.hlp?

In the days before Visual Basic for Applications, the macro language for Microsoft Excel was called XLL. The syntax was similar to that of ordinary Excel formulas, except for two things: Macros were ...
15
votes
2answers
2k views

First language with C-like memory management

This is a nerd question but I can’t find anything in google. So, in which programming language did the classical memory management system first be implemented? I mean the division into value types (...
2
votes
1answer
217 views

Was there ever a home PC which ran JOVIAL?

We are having a frank exchange of views here in the office. We were discussing the heydays of home PCs, back in the early 80s, when there were a plethora to choose from, most running some form of ...
12
votes
3answers
2k views

What's a good way to implement this “fade” effect on C64

See the beginning of https://www.youtube.com/watch?v=hmfLBAtGAKk. Here's a screenshot: It basically clears characters pixel by pixel both horizontally and vertically. Use sprites for the pixel by ...
18
votes
6answers
3k views

What caused the downfall of Pascal? [closed]

From 1985 to 1990 Borland's Turbo Pascal was at least as popular as C for DOS systems. Turbo Pascal was especially popular because of it's ground breaking BGI graphics interface while C was stalled in ...
15
votes
2answers
1k views

6502 branch offset calculation

This question expands on How does the 6502 implement its branch instructions? I'm working on a cycle accurate VHDL implementation on an FPGA. I have much of the program logic already written, but I ...
28
votes
5answers
7k views

Why was nil defined as a reserved word in Pascal?

In Pascal, nil (the pointer value to "nothing") is a reserved word. Why wasn't it simply a predefined identifier as true and false are, for example? This is stated in PASCAL User Manual and Report p....
5
votes
3answers
548 views

When were the analogs of the C operators “break” and “continue” introduced in Pascal?

When published in 1970, the Pascal language did not have a way to implement the functionality equivalent to the (future) C language operators "break" and "continue". Their convenience having been ...
30
votes
3answers
10k views

Where does this esoteric Pascal operator come from?

In the documentation for an implementation of Pascal for a Soviet computer, I've encountered a very weird language extension. I'll try to translate it: Branching operator (branch) Syntax &...
4
votes
0answers
127 views

How to use IIgs enhanced graphics modes in AppleSoft BASIC with System 6?

There are many packages that let you use the enhanced graphics modes of the IIgs in AppleSoft BASIC. However most packages like Iconix do not like System 6 so they have to run off disks and not the ...
28
votes
5answers
5k views

How was the C language ported to architectures with non-power-of-2 word sizes?

By the time the C language started to gain popularity outside of the PDP-11 circles (mid-1970s), mainframes with "weird" word sizes, and no capability to address individual bytes efficiently were ...
13
votes
8answers
1k views

Uses for the halt instruction?

What was the halt instruction in early CPUs such as the Z80 and 8080 used for? Here's a description of the Z80 instruction: The HALT instruction suspends CPU operation until a interrupt or reset ...
13
votes
3answers
737 views

What is going on in the overscan area of Sega Genesis games?

What is going on in the overscan area of Sega Genesis games? I noticed that different games display different things in the overscan area. I understand this was never intended to be seen. However,...
10
votes
4answers
2k views

What are the rules for Applesoft BASIC formatting for code?

What are the rules for Applesoft BASIC formatting for code? I've been doing some BASIC coding and noticed that: 10 input "some question?"; name$ Will be reformatted as: 10 INPUT "some question?";...
3
votes
4answers
513 views

Was there ever a compiler type that was just large enough to contain a memory segment?

From this answer, Hark back to the days of segmented 16-bit architectures for example: an array might be limited to a single segment (so a 16-bit size_t would do) BUT you could have multiple ...
6
votes
1answer
372 views

What is the title of this Macintosh programming book?

Back when Mac OS was called "System" and preemptive multitasking was a distant fantasy, I had a small collection of Macintosh programming books. For the life of me, though, I can't remember what one ...
14
votes
1answer
675 views

Fortran variable type defaults - origin

In older versions of Fortran, e.g. 77, variables did not need to be declared. If the name starts with I, J, K, L, M, or N then it would be assumed to be an INTEGER. Otherwise, it would be assumed to ...
10
votes
1answer
236 views

Does a CDC 1604 emulator exist with a functional FORTRAN compiler?

The first FORTRAN compiler for the Soviet BESM-6 mainframe was written by means of manually retargeting the assembly code of the CDC 1604 FORTRAN compiler donated by CERN to JINR. As a result is it ...
12
votes
6answers
1k views

Do any mainframe emulators exist with a functional FORTRAN compiler?

Similar to this question, but generalized to any mainframe computer from before the microprocessor era, does there exist an emulator and OS for a vintage mainframe computer that will run the output ...
0
votes
1answer
420 views

Is it possible to make VICE load .prg files faster?

When I load a C64 .prg with the Hoxs64 emulator, my .prg loads pretty much instantly. But when I load the same .prg file with VICE (x64 app.prg) it takes quite a while (depends on memory map, but ...
26
votes
4answers
1k views

Why were early versions of BASIC different?

Most major computer manufacturers/distributors in the 70's and 80's included BASIC with their computers. Some (as answers to this great question have detailed: Why was BASIC built into so many ...
2
votes
1answer
174 views

Is it possible to use the BRK instruction when ROM is banked out?

I used to use the BRK instruction when debugging on the C64. However, when I bank out ROM with... lda #$35 // Bank out kernal and basic sta $01 // $e000-$ffff ...the BRK instruction (...
1
vote
2answers
412 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. ...
20
votes
7answers
1k 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 ...
34
votes
4answers
11k views

Who is credited for the creation of Assembly Language?

The C Programming Language was originally developed by Dennis Ritchie who also co-designed the Unix operating system with which development of the language was closely intertwined. Is there a ...
10
votes
3answers
405 views

How do I store data and/or code in AUX RAM on an Apple //e?

Despite owning several Apple IIe's, I've never gotten around to doing any major programming on them. I hope to change that. Anyway, how did programmers actually use the expanded RAM seeing that a ...
25
votes
7answers
11k views

How can you run a program that is bigger than RAM?

Suppose you have a program that is 218 words long. However you are using a 16 bit machine and have 216 words of RAM. (The RAM is directly addressed by the CPU). On the other hand, you have unlimited '...
6
votes
2answers
339 views

What books did schools use to teach BASIC?

What books would have been used to teach school aged kids BASIC in a classroom setting back when BASIC was in common use? 8-Bit computers commonly came with tutorials to learn BASIC, like A Touch of ...
10
votes
2answers
572 views

Did the VIC-20 support raster scanline tricks like the Commodore 64?

I've been programming the C64 on/off for over 30 years (wow). However, I have a few VIC-20's I want to program. I never had a VIC-20 as a kid so I haven't had much exposure to them. Am I correct in ...
12
votes
3answers
2k 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. ...
5
votes
2answers
3k views

Best path to learn C64 assembly [closed]

The amount of tutorials, youtube videos, scanned books on C64 programming is overwhelming. What materials would you recommend -- and, importantly, in what order! -- to build a path to programming my ...
2
votes
1answer
394 views

How was the first working version of Google written?

Which language and/or server software did Google use for its initial version?
6
votes
2answers
413 views

Unsigned addition on the 6502

I am currently playing around with pointer and indirect addressing on the C64 and I encountered a problem with the ADC opcode. I am trying to increment a number repeatedly and when it overflows (goes ...
28
votes
4answers
7k views

Why (historically) include the number of arguments (argc) as a parameter of main?

A comment on this answer to a StackOverflow question made me curious. According the C99 standard, section 5.1.2.2.1: The function called at program startup is named main. The implementation ...
14
votes
2answers
1k views

What is the “standard” way to implement KERNAL hooks on the C64?

The C64 kernel (or KERNAL as it’s known in the C64 community) routines work via a jump vector table stored in page $03xx. A common programming paradigm to create something like a "device driver" would ...
8
votes
1answer
320 views

P′′ Language Interpreter/Compiler Resources

According to Wikipedia, P′′ is a "primitive computer programming language created by Corrado Böhm in 1964 to describe a family of Turing machines." P′′ contains only four instructions has influenced ...
15
votes
3answers
3k views

Do you need to allocate memory before you use it in MS-DOS?

In modern operating systems (for example: Windows), you can't access a memory location before you allocate that memory location to your program (or else a segmentation fault will occur). I am ...
4
votes
2answers
609 views

How hard would it be to port Amiga OS4 to x86 or ARM?

This question was raised on Facebook a few hours ago. Some say it's possible, others say impossible. What do you experts say?