I'm trying to compile and link an assembly file to an executable with NASM and the standard LD linker on my MacBook Air M1. I have no problems with getting the .o file, but if I want to link it with LD, it throws that error:
ld: file not found: elf_i386
Command:
ld -m elf_i386 -s -o hello hello.o
What do I have to change?
Those are options for GNU ld on x86 Linux. (Note the ELF part of the target object-file format, and the i386). MacOS uses the MachO object-file format, not ELF, and apparently their ld takes different options.
Also, MacOS hasn't supported 32-bit x86 for a few versions now, so an M1 mac with an AArch64 CPU definitely can't run 32-bit x86 executables natively.
So get an emulator for a 32-bit Linux environment if you want to follow a tutorial for that environment, or find a tutorial for AArch64 MacOS. Or possibly x86-64 MacOS which should still work transparently thanks to Rosetta, but make sure single-step debugging actually works. That's an essential part of a development environment for learning asm.
Assembly language is not portable at all, you need a tutorial for the OS, CPU-architecture, and mode (32-bit vs. 64-bit) that you're going to built in. Don't waste your time trying to port a tutorial at the same time you're learning the basics it's trying to teach. You'd have to already know both systems to know which parts of the code and build commands need to change.
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I am trying to do profiling of the code written in C++ with the target Architecture RISC-V. The code has been cross-compiled using RISC-V GNU Toolchain. My executable is unit_tests "ELF 64-bit LSB executable, UCB RISC-V, version 1 (GNU/Linux), dynamically linked,nterpreter /lib/ld-linux-riscv64-lp64d.so.1, for GNU/Linux 4.15.0, with debug_info, not stripped" this information is retrieved using the file command.
What I am trying to do is the profiling of this using gprof. But to do the gprof gmon.out needs to be generated, to generate gmon.out the executable should be run first. I cannot run the binary elf of other architecture in some different architecture. I need a suggestion for this on which emulator or simulator does this for me or I can run on?
I have tried installing qemu using the follwing link:
https://www.google.com/url?q=https://risc-v-getting-started-guide.readthedocs.io/en/latest/linux-qemu.html&sa=D&source=hangouts&ust=1597422417473000&usg=AFQjCNERr6pHYmj0SU6an3WkBRGQI52aTw
but not able to successfully install it.
Also have tried with spike but got "bad synccall" error. Any leads how can I resolve this issue.
I solved this issue using qemu in user mode. Following the instructions in the below link:
Manual-qemu-user
Where I could run the binary elf generated for target RISC-V, which I could run on x86 Linux machine.
When trying to run the ld command with the -melf_i386 option, i get this error:
ld -melf_i386 helloWorld.o -o hello
ld: unknown option: -melf_i386
This option does work on Linux.
How do I fix this?
You can't. macOS does not support ELF binaries, and its linker does not support ELF output. As such, the -melf_i386 option does not exist. (Indeed, the entire -m option for selecting an emulation does not exist either; macOS handles subarchitectures in a rather different way from Linux.)
If you are trying to create ELF binaries for a Linux system, you will need to install a cross-compile toolchain. I'm not aware of any prebuilt toolchains for this purpose; most developers targeting Linux systems do not compile software on macOS. A more viable option may be a Linux virtual machine.
If you are trying to create an ELF binary to run on the macOS system, you're out of luck. That isn't possible.
If you are trying to follow a tutorial on assembly programming, be warned that the macOS system call interface is not compatible with the one on Linux. Use a Linux system (or virtual machine) to follow this tutorial.
I'm trying to follow this blog but on Windows and with the latest Rust. It seems to me that the correct way of doing things like this is changing very frequently with Rust, so I'm hoping for an up-to-date Windows adaptation.
What I've tried so far:
I installed gcc-arm-embedded.
I had unverified partial success manually cross-compiling libcore, but then I switched to use the recommended xargo, the functionality of which (I read) is on its way to being included in Cargo eventually. While I don't understand any of it very well, I'm hoping to get to the part where I can write/run the code and then maybe I can back into understanding the compilation better.
With japaric's awesome help, I was able to get the "aarch64" targeted build working to generate the .o file (as of this particular commit).
And this part seems to verify:
$ file target/aarch64-raspi3-none-elf/release/deps/rust_rasp-ed0c2377e0a7df81.o
target/aarch64-raspi3-none-elf/release/deps/rust_rasp-ed0c2377e0a7df81.o: ELF 64-bit LSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
When I try to use the GNU Arm Embedded Toolchain linker, I get:
$ arm-none-eabi-gcc -O0 -mfpu=vfp -mfloat-abi=hard -march=armv6zk -mtune=arm1176jzf-s -nostartfiles target/aarch64-raspi3-none-elf/release/deps/rust_rasp-ed0c2377e0a7df81.o -o kernel.elf target/aarch64-raspi3-none-elf/release/deps/rust_rasp-ed0c2377e0a7df81.o: file not recognized: File format not recognized
collect2.exe: error: ld returned 1 exit status
And #rust IRC chatroom helpfuls told me that rpi3 is aarch64, not arm, so I need to find an aarch64 linker ...
I think it's working! Things I learned:
xargo is good
rpi3 is different enough from rpi2 to cause my problems in tool selection
xargo doesn't care what toolchain rustup defaults to because I'm not asking it to link for me and it does its own toolchain selection
I needed to target aarch64, not arm. For this I used the linaro aarch64 mingw32 download, unpacked, added its bin folder to my PATH. Then the aarch64 tools were easy to adapt from the blog.
For people who want to do this themselves, see https://github.com/JasonKleban/rust-rasp . Not so complicated!
I aim to blink the onboard activity led as confirmation that we do really have control, but looks like that will be kinda complicated on the rpi3 (see my readme, if still applicable)
I am trying to use msys powerpc-eabispe-gcc compiler on windows to compile a simple helloworld.cpp program, inorder to generate an elf for powerpc architecture, but I am getting "c++ compiler not installed on this system" error. The bin folder of powerpc-eabispe contains all the exe's, I dont understand why then I get this error??
I used MinGW command prompt to run this command: powerpc-eabispe-gcc.exe -o hello hello.cpp
You need to install the toolchain for the architecture you are targeting.
Search for "cctools" / "binutils" / "crosstools" or "ppc cross-compile environment".
You can also take a look at:
Building and Testing gcc/glibc cross toolchains (This will probably work)
Host/Target specific installation notes for GCC (search powerpc in the page)
However, I would encourage you to try this on a linux or on a mac computer. There are far more resources & docs available on the web for cross-compilation on these platforms.
Using MacPorts i have just installed arm-elf-gcc on to my MacBook Pro. This worked flawlessly and all seems to run fine.
However, after compiling a simple hello world test program in C and C++ and trying to run either on the target board (an ARM9 based board running Debian Linux) they immediately seg fault.
I'm a bit stuck as how to go about debugging this, as the target board has limited tools available and no gdb. I have successfully built and run other code using a Linux hosted cross compiler so it should work.
Any ideas?
Following the suggestion I have built and run gdbserver, I get the following in gdb on the host:
Program received signal SIGSEGV, Segmentation fault.
0x00000000 in ?? ()
I thought it may be a problem with the standard c libs so I removed any calls and have just an empty main that return 0, it is compiled with -Wall -g hello-arm.cpp -static. As a test I compiled the same source with a Linux hosted cross compiler and it runs and exits fine. The only difference I can see is the that Linux compiled version is over twice the size and the difference in output from the file command:
arm-elf-gcc: ELF 32-bit LSB executable, ARM, version 1, statically linked, not stripped
arm-*-linux: ELF 32-bit LSB executable, ARM, version 1, statically linked, for GNU/Linux 2.4.18, not stripped
The usual method of debugging in this situation is to run gdbserver on the target board, and connect to it (via ethernet) with gdb running on a host computer.
Alternately, you could try comparing the assembly in a Mac-compiled "Hello World" program and a (working) Linux-compiled one to see what's different.
After digging around for a couple of days I am starting to understand a bit more about embedded compilers. I wasn't really sure of the difference between arm-elf-gcc installed via MacPorts and the arm-unknown-linux toolchain I had installed on my Linux box. I just came across a pdf titled "An introduction to the GNU compiler" which contains the following paragraph:
Important: Using the GNU Compiler to
create your executable is not quite
the same as using the GNU Linker,
arm-elf-ld, yourself. The reason is
that the GNU Compiler automatically
links a number of standard system
libraries into your executable. These
libraries allow your program to
interact with an operating system, to
use the standard C library functions,
to use certain language features and
operations (such as division), and so
on. If you wish to see exactly which
libraries are being linked into the
executable, you should pass the
verbose flag
-v to the compiler.
This has important implications for
embedded systems! Such systems do not
usually have an operating system.
This means that linking in the system
libraries is almost always
meaningless: if there is no operating
system, for example, then calling the
standard printf function does not make
much sense.
So when I get back to my dev machine later I will determine the libraries linked in with the Linux build and add them to the arm-elf-gcc build.
I'll update this when I have more information but I just want to document my findings in case any one else has these problems.