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So recently I've wanted to learn assembly, so I learnt a bit. I put this into nano and saved it as playground.asm. Now I'm wondering, how do I compile and run it? I've already searched everywhere and still cant find it. I'm really curious and there's no point learning a language if you can't even use it.

Glorfindel
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Scorch
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    Nice to read such a question in times of gigabyte sized frameworks for all kind of problems :-) – PerlDuck Aug 12 '18 at 11:31
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    Take note that there are two major assembly "flavours" which have a different syntax: AT&T(gas) and Intel(nasm). Before choosing an assembler, you should decide which syntax you want to learn and use. See a detailed comparison chart here. If still unsure, go with Intel/nasm. – undercat Aug 12 '18 at 13:10
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    You can use gcc which should be installed on a standard Ubuntu machine by default. The file name extension is .s and the command to compile should be gcc myprog.s – FedKad May 01 '19 at 11:16

2 Answers2

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In all currently supported versions of Ubuntu open the terminal and type:

sudo apt install as31 nasm

as31: Intel 8031/8051 assembler
This is a fast, simple, easy to use Intel 8031/8051 assembler.

nasm: General-purpose x86 assembler
Netwide Assembler. NASM will currently output flat-form binary files, a.out, COFF and ELF Unix object files, and Microsoft 16-bit DOS and Win32 object files.

This is the code for an assembly language program that prints Hello world.

section     .text
global      _start 
_start: 
    mov     edx,len   
    mov     ecx,msg   
    mov     ebx,1   
    mov     eax,4   
    int     0x80   
    mov     eax,1  
    int     0x80   
section     .data
msg     db  'Hello world',0xa  
len     equ $ - msg

If you are using NASM in Ubuntu 18.04, the commands to compile and run an .asm file named hello.asm are:

nasm -f elf64 hello.asm # assemble the program  
ld -s -o hello hello.o # link the object file nasm produced into an executable file  
./hello # hello is an executable file
karel
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    Why would the as31 package be needed? From the question and the description of the package it doesn't sound like it would server a purpose. – kasperd Aug 12 '18 at 12:42
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    @kasperd Actually as31 is not needed. Inspired by the question I googled a Hello World in assembler, installed only nasm and it worked. :-) I think karel just mentioned it as an alternative. – PerlDuck Aug 12 '18 at 12:46
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    as31 is an alternative if you also want to learn assembly with as31. – karel Aug 12 '18 at 12:50
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    @kasperd: the OP did neither specify which ISA he is writing for, nor what assembly syntax he is using, so it makes sense to include as many options as possible. – Jörg W Mittag Aug 12 '18 at 14:02
  • @JörgWMittag The question does indeed not specify an ISA, it does however specify Ubuntu 18.04 which limits the options. Is Intel 8031/8051 among the CPUs which Ubuntu 18.04 can run on? – kasperd Aug 12 '18 at 16:07
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    This answer would benefit from splitting the installation command into nasm, and another for 8051 assembler + emulator (there seems to be at least one). Since the purpose is to learn assembly, actually running emulator for simple(r) architecture than x86 might make a lot of sense. – hyde Aug 12 '18 at 19:37
  • you have listed one proprietary assembler and one nonstandard, why not include a mention of gas (or as in general)? – cat Aug 12 '18 at 19:46
  • @cat NASM is under the BSD-Two Clause / FreeBSD, also most people perfer using the Intel syntax which is default for Nasm – Shipof123 Sep 10 '20 at 21:34
  • If I wanted to create a DOS executable on Linux, I might start your example with nasm hello.asm. Is a linker still then needed? If so, what would the invocation be? – user643722 Dec 06 '24 at 16:05
  • The executable format of the asm code at Creating a tiny 'Hello World' executable in assembly is still supported by modern Windows OSes, that run it inside a DOS emulator. In Ubuntu it runs successfully in dosbox with the command dosbox hello.com. Please note that I had to use the command nasm -f bin hello.asm -o hello.com to create the file named hello.com in my Ubuntu 24.04. The 'Hello World' code example from the website is without comments, but you can ask ChatGPT to add comments to it. – karel Dec 07 '24 at 01:47
  • That was the easy way. Here is the hard way. 1. Assemble the code into an object file with nasm -f obj hello.asm -o hello.obj 2. Link the object file using jwlink with jwlink format dos file hello.obj This command will create an executable DOS program named hello.exe. 3. Run the DOS program with dosbox or dosemu (example: dosbox hello.exe). – karel Dec 07 '24 at 09:02
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Ubuntu comes with as (the portable GNU assembler) 

as file.s -o file.out
ld file.out -e main -o file
./file

-o: Tells where to send the output
-e: Tells ld the start symbol

Thiago Lages de Alencar
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  • Thanks, this worked but I'm confused why I can't get it working with gcc... You wouldn't know how to do this with the gcc also would you? – Enjoy87 Feb 08 '25 at 11:24