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Questions tagged [68000]

The 68000 is a 16/32 bit CISC CPU, originally designed by Motorola, Inc.

The 68000 is a 16/32 bit CISC CPU, originally designed by Motorola, Inc.

After its introduction in 1979, it rapidly became popular among the system designers of its time. In its heyday, the 68000 was used in computers from Hewlett-Packard, Apollo/Domain, Sun Microsystems, Commodore (Amiga), Atari (ST), and Apple, among others.

Today, the 68000 and its derivatives are primarily used in embedded systems.

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What is on the 68000 stack when classic MacOS enters a program?

I'm trying to understand an old classic Mac application's entry point. I've disassembled the first CODE resource (not CODE#0, which is the jump table). The code refers to some variables off the stack: a word at 0004(A7), an array of long words of…
John Källén
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Help with 68k assembly - jump tables?

I'm working on reverse engineering a large Amiga program in IDA, and I've made a ton of progress. However, there is some stuff I can't quite figure out. Namely, I have found several subroutines which use what I believe to be "jump tables" - but I…
AriX
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Writing an OS for Motorola 68K processor. Can I emulate it? And can I test-drive OS development?

Next term, I'll need to write a basic operating system for Motorola 68K processor as part of a course lab material. Is there a Linux emulator of a basic hardware setup with that processor? So my partners and I can debug quicker on our computers…
ulver
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Programming Environment for a Motorola 68000 in Linux

Greetings all, I am taking a Structure and Application of Microcomputers course this semester and we're programming with the Motorola 68000 series CPU/board. The course syllabus suggests running something like Easy68K or Teesside Motorola 68000…
Nick Presta
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Difference between LEA and MOVE.L?

Are there any differences between LEA $1000,A0 and MOVE #$1000,A0 to put an address in the address registry?
dynamic
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68040 Takes Wrong Branch of If Else

Any good 68k assembly programmers out there?? I'm using a commercial Green Hills compiler for a Motorola 68040 and I'm seeing some very strange behavior from the code. Sometimes, the code will do an if/else comparison, and take the wrong branch. For…
Samuel
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Motorola 68000 assembler syntax for Program Counter Indirect with Index

I've been putting together my own disassembler for Sega Mega Drive ROMs, basing my initial work on the MOTOROLA M68000 FAMILY Programmer’s Reference Manual. Having disassembled a considerable chunk of the ROM, I've attempted to reassemble this…
msbit
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How to tell gcc to not align function parameters on the stack?

I am trying to decompile an executable for the 68000 processor into C code, replacing the original subroutines with C functions one by one. The problem I faced is that I don't know how to make gcc use the calling convention that matches the one used…
Maxim
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What ancient, old school code do you still have kicking around?

Having been bored out of my brains the last few days off work sick, I decided to try and dig up some old code. I could find some binary versions of some ancient Atari ST stuff I wrote, but I couldn't find any source. I did manage to dredge up an old…
Steven Robbins
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What is a circular shift with extend used for?

I remember in an assembly class, we learned the m68k processor, and there were 3 kinds of shifts you could do. Linear shift, circular shift, and circular shift with extend. The last one, circular shift with extend, basically rotates all bits left or…
DrZ214
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Do different 68k simulators have different TRAP tasks?

I've been revisiting Motorola 68000 programming lately. Admittedly, when I took the course I just did what was necessary to pass (and had a horrible professor)...but NOW I'm actually interested in the stuff. Anyway, looking through my old textbook…
Thomas
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Burst Mode Definition

I was reading up on computer organization and in the Memory chapter it mentions that "SDRAMS have several modes of operation, for example burst modes of different lengths can be specified." Can someone elaborate on what a burst mode is? The main…
rrazd
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Easiest way to merge 2 or more ELF files

I'm working on some embedded code for a class project that currently (per requirements) creates a number of srec files and merges them. I'd like to be able to load this code into QEMU, but it is generally only happy with ELF files. What is the…
megabytephreak
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How to convert my old amiga 68000 game to portable c

A long time ago, I've made some games for the Commodore Amiga. All done in 68000 assembly (So I still have the sources) I want to port these games to modern platforms, and instead of hosting an emulator, I thought of converting the Assembly to C,…
Toad
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GCC as m68k cross-compiler

I am trying to recompile binutils and GCC as a cross-compiler for m68k architecture. I am following these instructions: http://darkdust.net/writings/megadrive/crosscompiler However, the process keeps failing on one part or another. I have tried with…
aspirino67
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