Fasm For Mac


  1. Fasm For Macbook Air
  2. Fast Format Recover
  3. Fasm For Macbook
  4. Nasm For Macos
  5. Fasm For Macbook Pro

SASM supports 4 working with assemblers - NASM, MASM, GAS and FASM in 2 modes - x64 and x86. You can choose mode in settings on 'Build' tab. Also there you can change assembler and linker options and choose programs for assembling and linking.

  • MASM for x64 (ml64.exe); 3 minutes to read +1; In this article. Visual Studio includes both 32-bit and 64-bit hosted versions of Microsoft Assembler (MASM) to target x64 code.
  • This is the project webpage for the Netwide Assembler (NASM), an asssembler for the x86 CPU architecture portable to nearly every modern platform, and with code generation for.
  1. Mac Os X


    1. Running the installer (on macOS or Linux)
    2. Advanced usage

Fasm For Macbook Air

Fast formation

The FSL software suite requires the X11 windowing system - please install XQuartz before continuing with the FSL installation. The FSL install script will warn you if it is unable to find X11 on your computer.

Yosemite (10.10)+Recent versions of macOS are known to have problems with FSLView, often after major OS updates have been applied, if you experience errors referencing '/usr/X11R6' try re-installing XQuartz and failing this try: sudo ln -s /opt/X11 /usr/X11R6 ; sudo ln -s /opt/X11 /usr/X11

A recent FSL 6.0.3 patch for macOS users may fail the checksum when downloaded. If this happens, or to avoid the download integrity check entirely you can use the -M option with the fslinstaller.py script. For example: python fslinstaller.py -M

We have created an installation video which gives an overview of the installation procedure on a Mac.

The fslinstaller.py script carries out the installation of FSL, configuring your environment to enable you to run FSL from a terminal window (e.g. (/Applications/Utilities/Terminal.app on macOS).

Administrative privileges may be required

Installation into certain folders on your computer (e.g. the default, /usr/local) may require administrative privileges. If this is the case, the installer will attempt to gain these privileges through the use of the sudo command, which will require you to enter your password for verification. If you don't have permission to use sudo (an administration account on macOS) then the installer will fail and will need to either install into a folder belonging to your user or to run the installer as the root user. Should you install as root see the configuring your account for FSL section for details on how to use the installer to setup your user account for FSL.

The installer requires access to the internet to be able to download the FSL software appropriate for your platform and runs from within a terminal session, so you need to open a terminal:

  • Linux (Centos 7)
    • The Terminal application can be found in Applications > Utilities > Terminal menu

  • macOS
    • The Terminal application can be found in /Applications/Utilities

In the terminal change to the folder containing the fslinstaller.py file and run it with python; assuming that you wish to install into /usr/local (the default) then just press the Return key when the installer asks where to install to. For example if you downloaded to your Downloads folder:

The installer requires python 2.x to run which is the default on macOS and Centos 6 & 7, if you have installed python version 3 and made it the default when you run python then you will need to run it with a python 2 version, you can often find this as:

  • /usr/bin/python
  • python27
  • python2.7
  • python26
  • python2.6

Once the install completes Linux users should log out (System (top right icon) > Log out) and log back in to complete the FSL setup. If you are accessing the Linux computer via a remote SSH session then close the SSH session and re-login. Apple macOS users should open a new terminal window to begin using FSL.

if you use Mathworks' MATLAB it will configure your startup.m file to allow you to use the FSL MATLAB functions and on macOS platforms it will also install FSLEyes and FSLView into /Applications.

Advanced Options

Fast Format Recover


The installer has some advanced options which, amongst other things, allows you to:

  • customise the FSL installation location.
  • automate the FSL installation - this is useful if you would like to call the installer from an automated script.

Type python fslinstaller.py -h for a list of all available options.

Test that the environment and command line tools are set up correctly by doing the following:

  • Start a new Terminal session (File > Open Terminal under Linux/Gnome, Shell > New Window on macOS)

  • Check that your environment is correct by typing: This should display the name of the directory that you installed FSL in.
  • Check that your path is correct by typing: which should display a line like: (although the version number might be different).
  • Check that the miniconda environment installation completed successfully:
    • which should display a line like:

    If the imcp command cannot be found, this suggests that the FSL miniconda environment was not installed correctly - see the section titled Commands missing after installation on the main FSL installation page.

In general, to run the FSL tools from the command line (within a terminal) you need to enter the program name in lower case (e.g. bet). Typing a command on its own (without any arguments or options) gives you a help message for that command.


A more complete test of the FSL installation can be run, if desired, by using the testing and evaluation suite FEEDS.

To run a GUI version of a program you can either type its capitalised name with an additional '_gui' appended in the terminal (e.g. Bet_gui), or you can start the main FSL GUI by just typing fsl.

If this doesn't work the see the FAQ for how to go about fixing this, otherwise you are ready to run FSL.

Using FSL from MATLAB

On macOS, the fslinstaller script will usually set this up for you so you should not need to do this. However, if the installer cannot configure MATLAB for some reason you may need to do this by hand.

FSL ships with several MATLAB scripts for loading NIFTI files. These libraries are dependent on FSL environment variables which may not be set when you start up MATLAB from your desktop environment. You can configure MATLAB to be FSL-aware by adding the following to your ~/Documents/MATLAB/startup.m file (create it if it doesn't already exist):

Index>Unix > fasm on MacOS X [Snow Leopard / Lion]
Goto page Previous1, 2

Joined: 28 May 2012
Posts: 6
Hi guys,
I hope that this thread is still alive!
Following 'Shirk' excellent advices and tips, I successfully built FASM 1.70.02 on my OSX machines (32-bits and 64-bits).
I want to share the binary with everyone interested on programming with FASM under OSX (see USAGE file).
QUESTION for 'Tomasz Grysztar': 'Shrink' provided a patch (fasm-fix-out-of-memory-lion.diff.txt) which allow to compile FASM on OSX. Any chance to get it commited to FASM source code?

Description:FASM (v1.70.02) and OBJCONV (v2.14) binaries.
Allow you compile 32-bits and 64-bits FASM programs on OSX.

Filesize:258.3 KB
Downloaded:720 Time(s)

29 May 2012, 21:20

Joined: 08 Aug 2008
Posts: 13
30 May 2012, 04:31

Joined: 12 Sep 2011
Posts: 10
Uh, this got sticky - nice
Apparently I'm back to my pet os project, back to fasm and we still need the patched version.. (checked no path in 1.70.3 or 1.71 previews).
Not sure if Tomasz reads this forum / has interest in the patch but big thanks to zab for providing the binaries!
Maybe someone could mail him?
24 Sep 2012, 17:03
Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 7797
Location: Kraków, Poland
Tomasz Grysztar
I cannot approve such kind of fix. If that one relocation is processed incorrectly then the other relocations also cannot be trusted and it is inherently unsafe to try fixing it this way. One should rather search for the real source of the problem, that is the underlying bug related to relocations - and report it.
24 Sep 2012, 17:21

Joined: 12 Sep 2011
Posts: 10
Hi Tomasz,
please don't get me wrong - my post was in no way meant to insult anyone.
It was just written in a challenging tone to lure an answer out of you.
I agree that the real fix would be to determine why this one relocation is messed up. If you ask me - it's a flaw in objconv.. I looked through most of the code by now and everything else seems fine. (could be related to different reloc handling in mach-o).
But to be honest - osx or mach-o is nowhere near your target / planned features list and I neither have the time nor the fasm-guts to dig through the whole code to add a mach-o backend. So it looks like mac users are still dependent on this (possibly flawed, however working-fine-so-far) patched binary.
I'm fine with that and most of us can resort back to a VM if hard comes to hard..
so keep the thread sticky and most of us should be happy
P.S. - my vote for a fasm mach-o backend
25 Sep 2012, 05:52

Joined: 08 Aug 2008
Posts: 13
15 Dec 2012, 20:25

Joined: 08 Aug 2008
Posts: 13
Weird, can compile and run fasm.asm with fasm, but try to compile for efi and back to 'out of memory'
15 Dec 2012, 20:55

Joined: 08 Aug 2008
Posts: 13
ok changed buffer rb 1000h in fasm.asm to buffer rb 4000h
Now compiles efi
15 Dec 2012, 21:45

Joined: 08 Aug 2008
Posts: 13
Just compiled fasm.efi and works
I should note that fast.asm for efi already had buffer set to 4000h
so that appears to be the 'out of memory' bug
15 Dec 2012, 22:12

Joined: 08 Aug 2008
Posts: 13
OS X appears to need more buffer space as 1000h leads to 'Out Of Memory' errors and also leads to some examples that have buffer set to 1000h, getting errors too.
Is there a reason why OS X needs bigger buffer space??
Of course, it won't work otherwise.
So set the buffer to 4000h and you can do wonders.
16 Dec 2012, 06:21

Joined: 08 Aug 2008
Posts: 13
tools/libc/listing.asm is one example that now works.
As well as compiling fasm and fasm.efi from newest sources.
All this on Mountain Lion.
Anybody interested???

Last edited by STLVNUB on 17 Dec 2012, 20:07; edited 1 time in total
16 Dec 2012, 06:25

Joined: 09 Oct 2012
Posts: 161
Yep, as soon as my monitor works again.. And if i can get mountain lion up on a custom
16 Dec 2012, 06:44

Joined: 09 Oct 2012
Posts: 161
I've got ML running now.. it might be interesting to get fasm running
I found a few OSX Nasm examples too.. there was a quartz and an OPENGL one.. and a boilerplated hello world
http://forum.nasm.us/index.php?topic=1075.0 (OpenGL)
22 Dec 2012, 16:36

Joined: 09 Oct 2012
Posts: 161
looks like others have, and continue to play with macho-o. I think the above examples are good for understanding the bare minimum requirements for a macho32 and macho64. I just nasm assembled the second example off git and it works:

251 bytes on ML! hehe small enough to get to know macho bit by bit and byte by byte
im trying to see if i can get some function out of tinycc on osx with objconv [edit: tinycc can be used same way fasm works with objconvert and ld.. ld adds a lot of weight, probably a lot unnecessary.]

Last edited by KevinN on 02 Jan 2013, 14:53; edited 6 times in total
01 Jan 2013, 23:55

Joined: 09 Oct 2012
Posts: 161
here are some gui programs used as tools to examine macho:
02 Jan 2013, 00:13

Fasm For Macbook


Joined: 09 Oct 2012
Posts: 161
the source for cctools including ld, otool, as etc
02 Jan 2013, 07:00

Joined: 12 Sep 2011
Posts: 10
Nice analysis on mach-o so far -- I had a look into a fasm mach-o backend but tbh. couldn't find my way around mach-o 64..
@STLVNUB - the buffer size problems could be a result of things like the additional alignment requirements and other features like these that Xnu enforces.
19 Aug 2013, 10:01

Nasm For Macos


Joined: 23 Mar 2014
Posts: 79
I'm getting close to declaring official support of Mac OS X in my C compiler and just for the fun of it I made FASM executables out of fasm.o for Linux, Mac OS X and DOS/DPMI.
I used my compiler's C library and two pages of simple asm & C code to translate names (leading underscores are used by default in my compiler), preserve regs (my compiler preserves only the obvious: EBP, ESP) and intercept fopen() (it should really be called with 'rb' and 'wb' and not 'r' and 'w') and gettimeofday() (not implemented in my library, not part of the C standard).
The result seems to be working so far. I compiled a few C apps with my compiler instructed to use FASM in place of NASM.
Btw, the DOS/DPMI version is somewhat 'cleaner' in that it does not try to use unreal mode.
If anyone is interested I could share the code & instructions and the binary(-ies).
16 Oct 2017, 10:22

Joined: 23 Mar 2014
Posts: 79
So, it looks like my Smaller C compiler is working on Mac OS X 10.6 (Snow Leopard) through Mac OS X 10.12 (Sierra).
Here's how I turn fasm.o into various executables.

Compiling for MacOS:

Compiling for DOS/DPMI:

Compiling for Windows:

My compiler depends on NASM and the above asm code is for NASM, so you should have NASM 2.03 or newer if you want to recompile FASM using Smaller C and the above pieces of code.
Smaller C should work out of the box on Windows and DOS, just include the path to v0100binw or v0100bind in %PATH%.
On Linux and Mac OS X you can simply recompile the compiler, using the usual (you will need NASM already installed):

On Mac you may see an error from readlink, but it should still work.
I'm attaching the binaries.
What else?.. Feel free to poke around the compiler's library source for Mac OS X system calls. Ditto for the linker if you want to make 32-bit Mach-O executables by hand. Or you could just use the linker as-is.

Description:Precompiled FASM 1.71.64 for Windows
Filesize:66.51 KB
Downloaded:479 Time(s)

Description:Precompiled FASM 1.71.64 for DOS/DPMI (will need CWSDPMI)
Filesize:68.29 KB
Downloaded:473 Time(s)

Description:Precompiled FASM 1.71.64 for Mac OS X
Filesize:58.6 KB
Downloaded:464 Time(s)

18 Oct 2017, 03:44

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Fasm For Macbook Pro

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