Questions tagged [assembly]

For questions about Assembly Language in general. Also use the appropriate processor's tag.

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12
votes
1answer
437 views

Sprites not rendering correctly before $2000

I am currently testing out some stuff in assembly with C64Studio and Vice and I noticed something with odd sprites. My code starts at $1000 and my sprites at $2000 but when I try to lower the first ...
7
votes
1answer
512 views

Can someone help me get xROAR to read files? (M6809/TRS-80 ColorComputer)

I implemented a Forth interpreter or the TRS-80 Color Computer (M6809) way back in the 1980s, and I've been trying to figure out how to get it loaded into an emulator to test some parts of the ...
9
votes
2answers
716 views

Is the software available to simulate building a computer from the ground up? For example a system based on the 6502 [closed]

I recently got me head round the basics of how a CPU works after watching Ben Eaters 8bit bread board computer series of internet videos. Now I am hooked and i want to take my understanding further. ...
11
votes
2answers
1k views

What is the origin of different styles of assembly language mnemonics?

As exemplified in answers to this question (I hope that closed questions that are linked to, don't get purged), the instruction mnemonics in early assembly languages had a 1-to-1 correspondence to the ...
8
votes
1answer
320 views

How many bits are stored in a memory location in a PDP-11?

PDP-11 is said to be word addressable, which means every data access returns 16-bit data. Suppose I give a read request for address 100 in memory. Will it return 8 bits (LSB) from address 100 and ...
0
votes
3answers
761 views

Does anyone have the source code of an early program written in Assembly? [closed]

I am interested in looking at the source code of any program that was written in Assembly just about when the Assembly language was invented. If anyone have a source code for such a program, please ...
8
votes
1answer
141 views

cbm prg studio for the Amstrad

CBM prg studio is brilliant. I have searched Google for a version (or something similar) for the Amstrad CPC 464, to no avail. Does anyone know of one?
11
votes
3answers
839 views

How does 6502 machine code process $ (address) VS #$ (value)?

How does the 6502's machine code process $ vs #$, as in it's assembly language? Does every piece of machine code have an extra byte or something telling to use addresses or values or was it something ...
7
votes
3answers
598 views

Arithmetic operations on multiple words on the PDP-8

For the PDP-8 with its strange ISA, I've always wondered what the "standard" (i.e. fastest) way to do arithmetic operations (add, subtract, maybe multiply) on integers consisting of multiple words was....
14
votes
2answers
1k views

How could high level functions with return values map to 6502 assembly? (if at all possible)

What sort of code could be used to substitute a high level function with a return value to a 6502 subroutine? Take this C-like function for example. byte func(byte a, byte b, byte c) { d = (a + b)...
8
votes
3answers
610 views

Was The Telemark Assembler available for the Unix or Mac Environments?

I'm trying to build the recently released Infinity Game Boy Color source code on my macOS El Capitan box. The original development environment was a Windows box, and I'm trying to modify the build ...
11
votes
1answer
694 views

8080/8085 Instruction Test Suite

(This question was inspired by Comprehensive test suites for MOS 6520 PIA / 6522 VIA / 6526 CIA) Is there a comprehensive test suite for the Intel 808X series of processors? Something that would ...
8
votes
2answers
860 views

Intel 8080 Read/Set Interrupt Mask Instructions

According to Intel's 8080-8085 Assembly Language Programming guide, the OP Code 20 corresponds to the Read Interrupt Mask (RIM) instruction, and 30 corresponds to the Set Interrupt Mask (SIM) ...
52
votes
7answers
12k views

Why use static RAM addresses instead of the stack?

I'm studying the 65c816 assembly for the 1994 game, Super Metroid. A hobbyist studied the game in-depth and created a RAM map. From it: 7E:0B56 - 7E:0B57 Moves Samus this distance horizontally, ...
10
votes
3answers
2k views

What Commodore 64 emulator and assembler to use? [closed]

I'm about to do some assembly coding for the C64 but for sanity I would like to do the actual coding on my Mac with an emulator. My question is; which is the most maintained/up-to-date emulator/...

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