gas

I tried assembling some intermediate code generated by gcc. I used the command as -o hello hello.s , which, as far as I can tell, is the correct syntax. When I tried to run the program, it said bash: ./hello: cannot execute binary file . It doesn't seem like there's a problem with the assembly code, since it was the code generated by gcc, and it doesn't seem like there's anything wrong with how I invoked the assembler, since that seems to be the right syntax according to this manual . Can anyone help me with this? Working with GNU Assembler Assume that your assembly file is called hello.s and

I'm trying to write a firmware mod (to existing firmware, for which i don't have source code) All Thumb code. does anybody have any idea how to do this, in gcc as (GAS) assembler: Use BL without having to manually calculate offsets, when BL 'ing to some existing function (not in my code.. but i know its address) Currently, if i want to use BL ...i have to : -go back in my code -figure out and add all the bytes that would result from assembling all the previous instructions in the function i'm writing -add the begining address of my function to that (i specify the starting address of what i'm

Hi I have the following assembly code , .export __ls__11NSDOM_EncapFf .text __ls__11NSDOM_EncapFf: /* first load the symbolic constant*/ movq _IEEE_FP@GOTPCREL(%rip), %r8 /*%r8 is a scratch register*/ movq (%r8), %r9 /* %r9 and %r11 are scratch registers*/ movl (%r9), %r11d /* second, see if it is zero and branch accordingly */ test %r11d, %r11d /* zero call TNS procedure */ /* non-zero call IEEE procedure */ je ____ls__11NSDOM_EncapFf_tns/* constant equals 0 */ jmp ____ls__11NSDOM_EncapFf_ieee/* constant not equal to 0 */ ret I compile the .s file to .o file(compilation is fine) , but when I

I'm trying to do a very simple thing with gcc assembler extension: load an unsigned int variable into a register add 1 to it output the result While compiling my solution: #include <stdio.h> #define inf_int volatile unsigned long long int main(int argc, char *argv[]){ inf_int zero = 0; inf_int one = 1; inf_int infinity = ~0; printf("value of zero, one, infinity = %llu, %llu, %llu\n", zero, one, infinity); __asm__ volatile ( "addq $1, %0" : "=r" (infinity) ); __asm__ volatile ( "addq $1, %0" : "=r" (zero) ); __asm__ volatile ( "addq $1, %0" : "=r" (one) ); printf("value of zero, one, infinity =

This answer puzzled me. According to the standard C calling conventions , the standard way to call C functions is to push arguments to the stack and to call the subroutine. That is clearly different from syscalls , where you set different registers with appropriate arguments and then syscall . However, the answer mentioned above gives this GAS code: .global main .section .data hello: .asciz "Hello\n" .section .text main: movq $hello, %rdi movq $0, %rax call printf movq $0, %rax ret which works with gcc hello.s -o hello . The part that calls printf is: movq $hello, %rdi movq $0, %rax call

I've got some assembly functions I've ported to 64-bit ARM, and they work fine on Android, but when I tried to compile the same files in Xcode, I discovered that clang uses a different syntax (different from the official ARM documentation). I've found some scripts which convert a source file from one format to the other, but this is not the ideal solution (and it seems these scripts don't work when the source files contain preprocessor defines). Can I simply use gas in Xcode, or configure clang to accept the gas syntax? If not, where is the clang assembler documentation? UPDATE - September