Questions tagged [assembly]
Assembly languages in general, of any architecture. Use with the particular processor’s tag as appropriate.
268 questions
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Way to implement multi threading on a MOS 6502 type CPU [closed]
I'm trying to write an OS for the W65C02 CPU but i'm stuck because I have no idea on how to implement concurrency on such old CPU.
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8
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1
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"Paul's method" moniker for the 6502 RTS trick
In 6502 assembly programming, there's a common trick (usually called the RTS trick) for performing indirect jumps by pushing the target address minus one on the stack and executing a RTS instruction. ...
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Assemble a program for UNIVAC 1108
are there people here who can assemble such old programs? I have only 2 such codes that I would like to assembly but I don't know how.
Is this even possible?
1 Link: https://web.archive.org/web/...
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0
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Spy format expert part 2 (Apple IIgs)
It seems the Format Expert program has a hidden boot sector that can't be easily installed or extracted using the program because it's so obfuscated. This boot sector needs to be extracted in decoded ...
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How can a dummy learn assembler? (IIgs) [closed]
I would like to write some interesting programs in assembler but I don't know where to start and how to do it. I would like a guide in simple language for dummies. Does anyone have a list of such ...
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How to obtain error message text using MS-DOS interrupt 2Fh service 122Eh?
I'm trying to display error messages like a lot of MS-DOS (4.0+) utilities do. They don't embed messages like "Too many parameters" and "Invalid switch" in the executables, but ...
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309
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How to read/write tapes from PDP-11 on assembly?
Ok, I know this is a very old computer but just for fun. I have figured out how to read keyboard (0177560 for checking, 0177562 for reading) and print it (0177564 for checking, 0177566 for writing).
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Manual for the Microtec 6502 assembler?
The Atari OS, and I suspect other "major" programs from that era, was written using the Microtec cross-assembler. I have found manuals for the Intel version as well as their later 68k ...
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3
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16-bit comparisons setting both zero and carry flag on 8080/Z80
I have a routine cpBCHL that compares the contents of BC and HL and returns the carry set appropriately:
; ----------------------------------------------------------------------
; ♠BCHL ♣A ♡* ...
- 29.5k
8
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1
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Assembler/disassembler/etc to convert 6502 code to 65C02?
I'm wondering if anyone has ever come across a cross-assembler that takes 6502 code, in machine or assembler form, and converts it to use the new instructions available in the 65C02, or even the ...
- 22.4k
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Space Invaders ships remaining not initialized
I'm referencing this Space Invaders code.
(I'm porting this to another processor and I'm trying to understand it.)
The p1ShipsRem variable doesn't seem to be initialized, but it is tested early in the ...
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8
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1
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Original Space Invaders message routine with delay
I'm referencing this Space Invaders code.
Could someone explain why the PrintMessageDel routine checks for a delay value of one instead of zero?
The interrupt service routine decrements the isrDelay ...
- 943
8
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1
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707
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How was the first ever IBM PC BIOS image created? Can this process be replicated today?
According to dosfan, there are three known production versions of BIOS for IBM 5150 with the following datecodes: 04/21/81, 10/19/81 and 10/27/82. I am specifically asking about only the first one (...
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Reading a key in MSX without blocking?
Turbo Pascal 3.3 for MSX apparently didn't didn't have graphics, sound or other useful functions to write games, however it allows inline machine code to be injected by using the reserved word "...
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Did any processor (ISA) ever exist which didn't have well-defined signed overflow?
The C language always labelled signed overflow/underflow of integers "undefined behavior". I usually argue and say that this is an artificial construct created by C. On the assembler level ...
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