8 years ago In order to fix, we need a new yasm binary on the Windows 32-bit build machines. The build came in just this weekend, so right now it's only in the trunk. We need the same binary for on Windows and Mac 32-bit. There are some other systems (at least Linux 32 bit) that require at least yasm 1.0. I figure we should probably upgrade all the machines to the trunk yasm. I've confirmed that rev 2348 does what I need. Builds are available at The yasm devs have indicated to me that they might be willing to spin a 1.0.2 release (containing the necessary fixes) sometime soon.

I can inquire further about that if it would be preferable.

I want to compile and execute a very simple program in 64 bit. Section.text global start start: mov rdx,len mov rcx,msg mov rbx,1 mov rax,4 int 0x80 mov rbx,0 mov rax,1 int 0x80 section.data msg db 'Hello, world!' ,0xa len equ $ - msg The line to compile it: yasm -f elf64 -g dwarf2 example.asm $ yasm -version yasm 1.2.0 also tried with another format macho 32 64, elf 32 bin none of them succeed. The line to link it: gcc -o example example.o ld: warning: ignoring file example.o, file was built for unsupported file format ( 0x7f 0x45 0x4c 0x46 0x 2 0x 1 0x 1 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 ) which is not the architecture being linked (x8664): example.o Undefined symbols for architecture x8664: 'main', referenced from: start in crt1.10.6.o ld: symbol(s) not found for architecture x8664 collect2: ld returned 1 exit status $ gcc -version i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. Build 5658) (LLVM build 2336.11.00) also tried with some options for gcc such as -m64 -arch x8664.

You have a few problems here: 1) ELF is not supported on OS X, only Mach-O. 2) Your linker is looking for an x8664 architecture Mach-O and not finding it. Ld: warning: ignoring file example.o, file was built for unsupported file format ( 0x7f 0x45 0x4c 0x46 0x 2 0x 1 0x 1 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 0x 0 ) which is not the architecture being linked (x8664): example.o Make sure you're assembling for x8664 or else try passing -m32 to GCC to use x86.

3) Your linker is trying to include the C runtime library crt1.10.6.o, which doesn't look like what you want since you didn't define a main function. Perhaps you should call the linker directly instead of invoking it via GCC, or else find the right combination of flags to pass to the linker to avoid this. If I was you, I'd start with the following steps: a) Write hello world in C, have clang output an assembly file (-s), and then see if you can assemble and link that using just clang. This should be pretty straightforward. B) Once that works, use file and otool to determine what your object file should look like and try to produce that with yasm. I have been working on assembly language for OS X using yasm.

The assemble line is: yasm -f macho64 -l file.lst file.asm Then link with ld: ld -o file file.o You should use start rather than start on OS X. Following that there is a problem using gdb.

Yasm Ubuntu

There does not seem to be any debug format available for OS X. You might be interested in trying my IDE named ebe. I have managed to get breakpoints and debugging to work fairly well.

Currently I have some issues with debugging floating point code. Gdb doesn't seem to be aware of the ymm registers and the default version of gdb had the parts of the xmm registers backwards. You might like ebe. Download it from sourceforge using git clone git://git.code.sf.net/p/ebe-ide/code ebe It requires xterm, python, tkinter and pmw (a python library).