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So, I have an assembly function, which is called in C. It compiles and gives me no warnings, but when I try to run it, it gives me a segmentation fault. I think it's because I can't move a constant into a register, but to use the mul/div command it requires a value to be in EAX register. How can I multiply or divide two constants in Assembly? Here's the code so far... .section .data .global n .equ A, 50 .equ B, 5 .section .text .global loop_function loop_function: # prologue pushl %ebp # save previous stack frame pointer movl %esp, %ebp # the stack frame pointer for sum function # beginning

I am currently learning Assembly language on Linux. I have been using the book 'Programming From the Ground Up' and all the examples are 32-bit. My OS is 64-bit and I have been trying to do all the examples in 64-bit. I am having trouble however: .section .data .section .text .global _start _start: movq $60, %rax movq $2, %rbx int $0x80 This merely just calls the Linux exit System call or it should. Instead it causes a SEG FAULT and when I instead do this .section .data .section .text .global _start _start: movq $1, %rax movq $2, %rbx int $0x80 it works. Clearly the problem is the value I move

I used homebrew to install GCC 4.7.0 and my project's make is failing at assembly-time. I can successfully take code from .c -> .s, but .s -> .o fails. To view the brew formula used to install GCC, please look at: https://github.com/Homebrew/homebrew-dupes/blob/master/gcc.rb . I also installed binutils from upstream using https://github.com/mxcl/homebrew/blob/master/Library/Formula/binutils.rb . Install binutils does not appear to introduce a new 'as' in the /usr/local/lib or similar. How can I track down this missing instruction error? It appears the compiler is correct but the linker simply

In the following assembly code that I dumped out using objdump : lea 0x0(%esi,%eiz,1),%esi What is register %eiz ? What does the preceding code mean? See Why Does GCC LEA EIZ? : Apparently %eiz is a pseudo-register that just evaluates to zero at all times (like r0 on MIPS). ... I eventually found a mailing list post by binutils guru Ian Lance Taylor that reveals the answer. Sometimes GCC inserts NOP instructions into the code stream to ensure proper alignment and stuff like that. The NOP instruction takes one byte, so you would think that you could just add as many as needed. But according to

Whilst learning the "assembler language" (in linux on a x86 architecture using the GNU as assembler), one of the aha moments was the possibility of using system calls . These system calls come in very handy and are sometimes even necessary as your program runs in user-space . However system calls are rather expensive in terms of performance as they require an interrupt (and of course a system call) which means that a context switch must be made from your current active program in user-space to the system running in kernel-space. The point I want to make is this: I'm currently implementing a

Test platform is 32 bit Linux. Basically, I know gcc can be used to generate both Intel and At&T style assembly code, but it seems that you can not directly use nasm/tasm to compile the Intel style assembly code gcc generated. I am conducting a project analysis asm code on both windows and Linux platform, so I am thinking if they can be both compiled by platform independent assembler like nasm\yasm, I could have a much easier time... So my question is how to generate a nasm compilable assembly code from c source code on Linux? Babken Vardanyan I find it's a better approach to disassemble the