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How to detect a real Commodore 64, THEC64, or VICE emulator in software?
Some programs notice if they are run on a real Commodore 64 or an emulator. For example, this demo from 2007 stops on VICE emulator 3.2 with the message "No VIC inside". How is this done?
I found some code to identify a Commodore 128 in Commodore 64…
Peter B.
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When did the IBM 650 have a "Table lookup on Equal" instruction?
In 1959, Donald Knuth wrote an assembly program named SuperSoap for the IBM 650. Here is the manual, and here is a listing of the program (in SuperSoap assembly language). Quoting from the abstract:
SuperSoap is a major revision of Case SOAP III…
texdr.aft
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Why user-assembled kits?
Many early computers were sold as self-assembly kits (you get a box of parts and an instruction leaflet and have to solder them together yourself). For example, the Altair was priced at $439 kit, $621 preassembled.
The obvious rationale for offering…
rwallace
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22
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Why were there no 32-bit versions of 65xx CPUs, or 64-bit versions of m68k CPUs?
I don't understand why Western Design Center made the 65816 a 16-bit upgrade to the 6502 but Commodore Semiconductor Group/MOS Technology didn't make their own variant & why neither company made 32-bit or 64-bit versions of the architecture.
Also I…
6502Assembly4NESgames
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Where and when did the ".s" suffix for assembly-language source files originate?
The closest I was able to find on StackOverflow is What are .S files?, in which no answerer addresses why we use .s for assembly. (And .S for preprocessor/macro assembly; and gcc -S to produce assembly...)
(By "we," I mean basically the POSIX…
Quuxplusone
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When IPv6 was designed were there any specific considerations for other planets?
Seeing Moon base internet functionality in Worldbuilding reminded me of how I began an old Space SE question Are there discussions or plans for extending the internet into space beyond Earth?
Many years ago I remember reading about the upcoming…
uhoh
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When if ever was the C language 'int' size altered from the host machine word (register) size into a literal 32 bit size?
From the earliest K&R reference manuals I read, 'int' was synonymous with machine word and it seemed to raise adverse reactions in various user domains. With the UNIX crowd, they minimally required an MMU(Note *1) so the word had to be 32bits at…
MKhomo
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Glitch in the display of a Mac SE/30
I found an old Macintosh SE/30 in the basement and fired it up recently, only to find that there's some kind of problem with the built-in CRT. I don't really know how to describe it, though. Can anyone identify the glitch shown in this image?…
maldata
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Which CPUs, if any, had an 8-bit address space?
Even the Intel 4004, which had a 4-bit word size, had a 12-bit address space. I'm wondering if any commercial CPUs had an 8-bit or similar address-space for programs, data, or both.
I'm particularly curious about CPUs with small program…
lookaside
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Where to buy a 6502 chip
I want to purchase a 6502 40 pin CPU in order to verify if my 6502 is faulty, I've seen I can buy from Hong Kong but would prefer closer (to the UK), RS and CPC don’t seen to have any.
Most answers suggest trying a 65c02 processor but these all seem…
Bigmalc40
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Will disassembling an 8080 program as Z80 code work?
The Z80 is "binary compatible" with the 8080. It adds a bunch of new instructions, but places them all in unused (well, undocumented) opcodes.
Does this mean that if I disassemble an 8080 program (which doesn't use any undocumented opcodes,…
tobiasvl
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Was there any automated unit testing prior to 1972?
Prior to 1972, was there any automated unit-testing? Did any assemblers include a testing a framework?
I can find some academic journals on this topic from the late 70s -- most of which I don't have access too, but I don't see any implementations or…
Evan Carroll
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Why was NEC able to wrestle PC graphics standards away from IBM?
The dominant standards for PC graphics in the 1980s were the ones introduced by IBM. This included MDA and CGA with the original IBM PC, followed by EGA shortly after the PC/AT, and then VGA with the PS/2 line. While there were other popular cards…
Brian H
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Are pixels on the Commodore 64 square?
Are "tile pixels" the same size as "sprite pixels", and are they both square (ignoring the rule that multicolor sprites can only be colored in groups of two pixels)?
By "square" I mean that the pixels have a 1:1 aspect ratio.
If the answer depends…
Woodrow Barlow
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Why did the Z80 with 4-bit ALU out-perform the fully 8-bit Intel 8080?
Looking at the development and architecture of the Z80, it appears to be a scaled-down, cost-reduced (in terms of total system cost), clone of the Intel 8080. It only used a 4-bit ALU. I assume this would have reduced its performance…
Brian H
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