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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Does unused code affects the assembly after startup (Memory for example)?

Disclaimer: I come from a PHP background. In PHP, I could have thousands files, which are never loaded, if not needed, due to the autoloader feature (If some code is needed, it would be loaded) How ...
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3answers
712 views

Development process used for the code on Apollo 11 missions?

The Apollo missions had technology no more complicated than a pocket calculator. From link here, there's an information about Apollo Guidance Computer (AGC) The on-board Apollo Guidance Computer ...
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What's the REAL benefit of using CDECL? (more specifically pushing instead of reg-ing)

So, I'm learning assembly, and I've come to know the ABIs and i got some basics tests working using the cdecl calling convention to use the c's stdlib under nasm. But I've seen other Calling ...
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98 views

Unit Testing: Assembler code and different architectures

I am currently unit testing some C code and I am faced with a problem: Within the code there are called functions that contain inline assembler code for the SPARC 8 architecture. Since I am doing ...
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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 ...
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4answers
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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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1answer
92 views

How to be sure that a certain code does not call interrupts?

Imagine that you have an object code file from an untrusted source. You want to run this code to know the result of its computation, and you want the code to perform fast, so setting up a whole ...
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2answers
116 views

Difference in endianness between operating systems [closed]

There is an assembler that I am writing that is located within the file asm.c located in this repository. It uses the instruction set located in the specs file to produce an output binary. (The ...
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18k views

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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7answers
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Will hand-written assembly disappear? [closed]

Last week I was wondering, with compilers getting better and better at optimizing, will there be a point when there is no need for hand written assembly? Are there still specialized fields where the ...
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0answers
250 views

Writing Z80 table based assembler/disassembler

I have a long-term project: DIY computer with various processors. One of my wishes not only make hardware, but software too. So I started from assembler/disassembler for Linux, though there is a lot ...
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4answers
516 views

What are the key differences between low-level C development and higher level OOP development? [duplicate]

I have been using high-level OOP language (like C# and/or Java) for quite some time. I know patterns like the gang of four, can read and write code reasonably well and am considered a senior by his ...
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2answers
329 views

Best x86 processor(computer) to learn computer architecture and assembly [closed]

I'm planning to build a computer as a hobby from scratch, with the least basic hardware possible in functionality so I can learn the basics of computer architecture and assembly language. I already ...
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0answers
47 views

IBM PC XT 5162 even and odd BIOS

I am writing a whole new BIOS, from scratch, for the 5162. The already existing BIOS is on chips U34 and U35. Normally, exactly one byte (the odd byte) should be on U34, followed by exactly one even ...
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3answers
2k 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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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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1answer
412 views

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

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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11answers
10k views

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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6answers
9k views

Is Assembly still relevant? [closed]

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 ...
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9answers
12k views

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 ...
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6answers
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What came first, the compiler, or the source?

I'm curious about the birth of the compiler. How did programming begin? Did people first build hardware that recognized a certain set of commands, or did people define a language and then build ...
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3answers
6k 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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1answer
72 views

SPARC and Assembly [closed]

I'm currently self teaching myself programming and became familiar with Python, Java and C and I'm confused as to what are the differences between Assembly and SPARC Assembly and whether or not I ...
122
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18answers
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How does learning assembly aid in programming?

I have been programming in higher level languages (Python, C#, VBA, VB.NET) for around 10 years and I have completely zero understanding on what's going on, "under the hood." I am wondering what are ...
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10answers
779 views

Assembly in a research paper

I am doing a research paper on programming, and I need to somehow explain assembly... I've never learned the language, but I understand what it is used for and kinda what it looks like... MOV A,47 ...
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2answers
355 views

Why was the AT&T assembly syntax designed this way?

The AT&T assembly syntax, often called the GAS syntax, keeps surprising me. For example, its parameter order: mov $100,%eax /* Destination after source */ This just seems so counter-intuitive! ...
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1answer
241 views

How to make absolute jumps relative?

Given I have x86 assembly code disassembled into a list of structures that fully describe it (opcode, regs, imm etc.). How can I now programmatically turn absolute jumps to relative jumps? Basically ...
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1answer
232 views

Can SSE (or AVX) be used to do large bsf?

I'm faced with having to do a bsf (find the first bit set) in a 512bits bitmap. This is in the hot path so I'd like to see how I can speed things up. Right now I'm maintaining a header entry to know ...
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0answers
72 views

How does a .COM file get loaded for execution

For a bit of fun I thought I would start writing my own emulator for the 80286. I have been reading a bunch about the topic. I thought for simplicity I would start with a really simple COM executable ...
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5answers
4k views

Advice for an ambitious student on building your own kernel [closed]

I'm a very ambitious university student who wishes to learn pretty much everything there is to know about computers (bash me if you want, I love learning). Recently I thought it would be a fun project ...
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1answer
231 views

Longest x86 Instruction

I read the recent article "Longest x86 Instruction" http://blog.onlinedisassembler.com/blog/?p=23 I attempted to reproduce the curious disassembly issue on a Win7x86 development platform using masm ...
2
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3answers
229 views

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
114 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
168 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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15answers
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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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1answer
340 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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7answers
22k views

What Are Some Advantages/Disadvantages of Using C over Assembly? [closed]

I'm currently studying engineering in Telecommunications and Electronics and we have migrated from assembler to C in microprocessor programming. I have doubts that this is a good idea. What are some ...
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2answers
600 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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1answer
377 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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3answers
632 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
990 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 ...
2
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2answers
127 views

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
392 views

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 ...
0
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2answers
116 views

How do we add software to a machine? [duplicate]

When we build a new machine, how do we add software to that machine? I know we have assemblers and compilers that convert the high-level code into machine code for it to understand. But having ...
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2answers
385 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. ...
6
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2answers
1k views

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. ...
2
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1answer
395 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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631 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
291 views

Why do we need a format for binary executable files

When binary files (i.e. executables) are saved they usually have a format (e.g. ELF or .out) where we have a header containing pointers to where data or code is stored inside the file. But why don't ...
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4answers
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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 ...