An assembly language is a low-level programming language for a computer, microcontroller, or other programmable device, in which each statement corresponds to a single machine code instruction.

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Editing assembly code for 68HC11 Micro? [on hold]

1 ORG $0020 start of RAM (data) 2 AT1 RMB 2 3 Space RMB 1 4 Length RMB 1 5 Count RMB 1 6 Ptr RMB 2 7 ORG $E000 start of ROM (program) 8 START ...
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8085 assembly question. Why flag stacks named d0-d7?

I'm trying to make my C programming exciting by learning assembly programming. I've encountered an image of flag registers in 8085 assembly programming. In that image blocks are named from ...
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2answers
66 views

How were assemblers created straight from binary? [duplicate]

How did these earlier programmers know what combinations of binary produced certain results? Is there a way I can create an assembler from binary today?
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1answer
102 views

Implementing a VM for simulation [closed]

I am aware of this question, and I think I know why it has been closed. I hope that my question manages to be more specific. My skill level: I have a "Computer Science" degree. I have programmed in ...
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How have languages influenced CPU design? [closed]

We are often told that the hardware doesn't care what language a program is written in as it only sees the compiled binary code, however this is not the whole truth. For example, consider the humble ...
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Were the first assemblers written in machine code?

I am reading the book The Elements of Computing Systems: Building a Modern Computer from First Principles, which contains projects encompassing the build of a computer from boolean gates all the way ...
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169 views

Developing a compiler for a self made CPU Architecture

Recently ive been consumed by creating my own simple CPU architecture that at some point could be easily implemented in hardware (No FPGA, but actual Logic Gate circuits). Naturally to fulfill this ...
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2answers
329 views

Why convert to assembly language instead of machine code?

When I compile a C program, it is compiled first to assembly code, then assembled into machine code. I'm curious why it doesn't just convert straight to machine code in the first place.
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188 views

Why does GCC use AT&T syntax by default?

I think title says it all :) Is there any particular practical reason (I guess it's mostly historic, but I'm unable to find it on my own) why GCC uses AT&T/GAS syntax? Note: I know this is just ...
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243 views

Assembly vs. algorithmic languages (like C, Algol, etc)

Usually, computer science papers describe algorithms in Algol-like pseudolanguage, similar to Pascal or even C/C++. But Donald Knuth uses his own assembly language (MMIX). Are there any good known ...
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351 views

How Byte loading/storing is implemented By the CPU?

I know that in 32bit machine, cpu read from memory 32bits at a time. since the registers in this case is 32bit in size too, I can understand how this works. What I don't understand is how the cpu ...
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1answer
294 views

Polymorphic engines in C and/or C++ [closed]

I stumbled across polymorphic engines and I don't know anything about them. However, I am curious about how they are written. Every example that I've looked up writes them in assembly, my assembly is ...
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gcc -S seems a bit misshapen with shifting and ANDing bits

Example: int c = 4; int p = 5; if (p & (1 << c)) printf("ok\n"); else printf("nop\n"); gcc -S: movl -4(%rbp), %eax /* eax holds the variable c */ movl -8(%rbp), %edx /* ...
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1answer
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What are steps in making an operating system in C ? [duplicate]

I am trying to make an my own OS. This is for educational purpose only, so that I get to understand the internals as well as get a good idea of low level programming. I have some prior application ...
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2answers
208 views

Reading assembly useful for insights when writing C/C++? [closed]

While in most cases its not necessarily, recently I have taken to reading the generated assembly of my C code every so often, when I'm curious as to the kinds of optimizations my compiler is making. ...
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2answers
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How are OOP “objects” and “classes” organized in memory in terms of assembly language?

How are objects organized in memory? For instance, I know that a function is a piece of code in memory, that expects parameters via the stack and/or the registers and handles it's own stack frame. ...
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1answer
164 views

How do VMs implement function calling?

I'm reading a compiler textbook that compiles to some form of assembly. Since I don't know this assembly language I decided to invent my own simple "assembly language" and implement a basic "virtual ...
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2answers
531 views

If statements in “generic” assembly?

I'm reading a relatively 'friendly' and simple book about compilers named "Let's Build A Compiler" (originally a series of articles). The compiler written in the book generates instructions in some ...
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3answers
976 views

Is there still any value in learning assembly languages today? [closed]

Specifically for a game programmer. If you really needed some assembly routines you could look for help, whereas back in the 80s/90s it was one of the mainstream languages. I read that compilers can ...
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4answers
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Why does Donald Knuth write TAOCP using assembly language?

I don't hate using assembly language, since I have written some in my os course. But obviously, assembly language lacks abstraction, you have to pay more attention to the details. Is assembly ...
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16answers
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Assembly as a First Programming Language?

How good of an idea do you think it would be to teach people Assembly (some variant) as a first programming language? It would take a lot more effort than learning for instance Java or Python, but one ...
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4answers
732 views

How does assembly relate to machine/binary code

How does assembly relate to machine/binary code. For example here is how to print to the screen in mikeOS(a small pure assembly OS), mikeOS it uses NASM to assemble. BITS 16 ORG 32768 ...
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5answers
170 views

What conclusion to be drawn from no difference in generated assembly from 2 rather different programs?

I might not have had a counterexample when I got the reply "A pointer is just an address, what's the difficulty?" but I didn't really buy such a simple explanation and at assembly code it's not ...
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4answers
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Why do we use to talk about addresses and memory of variable in C?

Why do we use to talk about addresses and memory of variable in C, where in other languages (like in Java, .Net etc) we do not talk about variable address and memory in a program, we will directly use ...
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5answers
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Is there a canonical book on x86 assembly? [closed]

There are lots of books on assembly. However, they usually deal with ISAs about which I don't care, such as MIPS or ARM. I don't deal with these architectures; there's no reason for me to try to learn ...
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258 views

Creation of an Assembler [closed]

I've always been interested in how programming languages are created, so for the past 8 months I've been researching, practicing and more about the creation of compilers. I've been able to quite ...
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1answer
814 views

What is the purpose of red zone?

Red zone is a fixed size area in memory beyond the stack pointer that has not been "allocated". Compilers do generate assembly to access that area in simple leaf functions. But I can't see any real ...
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1answer
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Fetching instructions from memory

So, I am a noob in assembly language and machine instructions. When the discussion came up as to how funtion calls are implemented at the processor level, someone said that the CALL instruction ...
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How do we go from assembly to machine code(code generation) [closed]

I know this is abstract as it's all about signals and switch - (electronics) - underneath, but is there a easy way to visualize the step between assembling code to machine code. For example if you ...
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1answer
167 views

What did machine code for 4-bit architecture look like?

I don't know how a 4-bit instruction could be enough to do something so I read about the Intel 4004 and it says that it used 8-bit instructions and then I can understand how opcode and numbers has ...
16
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4answers
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Is Assembly still relevant?

Are there major differences between assembly language and higher level languages when it comes to coding and/or managing projects? Obviously it takes more statements in assembly language to carry out ...
12
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3answers
698 views

Why is the copying instruction usually named MOV?

In quite many assemblers, a value copying instruction is usually named "MOV" and its description in manuals usually also contains "move" (however, other words can be used, like "load", "store", ...
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3answers
455 views

Why do some compilers generate direct machine code?

I was taking this course - CMU 18-447, Computer Architecture at Carnegie Mellon to brush my knowledge and concepts. They say that most of the machine level details and implementations is taken care ...
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Purpose of NOP instruction and align statement in x86 assembly

It has been a year or so since I last took an assembly class. In that class, we were using MASM with the Irvine libraries to make it easier to program in. After we'd gone through most of the ...
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588 views

How are I/O port addresses and data sent?

First of all, I'd like to say this is a hardware-level question, which is very closely related to the "in" and "out" command in x86 assembly. I have searched for quite some time, but I still haven't ...
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Is this an assembly language?

In my childhood I used to program on an MK-61 Soviet calculator. It had four operating registers (X, Y, Z, T) and 15 storage registers. A program could have 105 steps. As I recall it, it had commands ...
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3answers
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Is there much difference between X86 Assembly language on Windows and Linux?

I'm a complete beginner at Assembly, and my aim is to learn as much as I can to do with Assembly to one day I can reach expert level (I know I'm way off right now, but you never know). My only problem ...
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Writing a bootloader with no bootloader

I have a question that I really can't find a straight answer to. Let me start by saying I'm not asking for a step by step tutorial, or even plan on doing anything. I'm just curious. I've been ...
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1answer
278 views

Any good, easy to learn from books or tutorials for learning assembly? [closed]

I've been a developer since 2009 and I've learnt a lot of languages since, but I've always wanted to understand and be able to code in the lowest level language so I can directly (or at least very ...
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7answers
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How were the first compilers made?

I always wonder this, and perhaps I need a good history lesson on programming languages. But since most compilers nowadays are made in C, how were the very first compilers made (AKA before C) or were ...
41
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5answers
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How can this all fit into 64kb?

So, I am here at assembly 2011 and there was this demo played: http://www.youtube.com/watch?v=69Xjc7eklxE&feature=player_embedded It's one single file only, it says that in the rules. So I ...
5
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2answers
748 views

Implementing non-fixed length array support in a compiler

I'm thinking of building a language for PIC microcontrollers. I want to be able to use non-fixed size arrays, like this: Declare the variable as int[] Wait for input from serial connection Make the ...
3
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2answers
1k views

will an assembly language book for intel x86 processor be compatible with amd processors?

I'm wanting to get an assembly book to learn assembly, and was wandering if i get a book for intel x86 processor will there be any problems assembling the code on an amd processor?
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1answer
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Frame Pointer Explanation

In MIPS assembly, there is a register for the stack pointer, and another register for the frame pointer. What is the frame ponter and what is its purpose. How does it differ from the stack pointer?
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Is a “build” assembly?

In an old book I have, they say that "build" is either a process of converting source code into executable or the actual result - assembly. Is that correct? Is a build actually the assembly, I mean ...
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1answer
543 views

Using assembly to write to a file

I am working with a trading application (reading data from the exchange) which generates a bucket load of data on a per second basis. We have different "log-levels" but even the minimal log-level ...
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3answers
382 views

How can I get assembly from an EXE? [closed]

Pretty much my only question is the title. Other then that I want to see the code behind small EXEs but I know it's hard to get it to convert to something like c or c++ so why not get assembly.
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3answers
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Is it possible to use GNU GPL for application that has no source?

I mean, it is possible to create application without source code - for example using HEX editor or some debugger that can assembly instructions (actually every decent debugger can). Creating programs ...
12
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3answers
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I want to build a Virtual Machine, are there any good references?

I'm looking to build a Virtual Machine as a platform independent way to run some game code (essentially scripting). The Virtual Machines that I'm aware of in games are rather old: Infocom's ...
10
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Learning to Program in Assembly - Useful Resources [closed]

Following on from a previous thread, it has got me interested in learning a little about Assembly programming. Not so much for wanting to program useful apps in, just to get a feel for low level ...