c - Accessing calloced array in GAS assembly -

i have c function allocated memory array going filled natural numbers n.

lets say,

n = 10; array = calloc(n, sizeof(int)); 

i call upon assembly function have written, don't seem able access array fields. manage find value of n located @ 8(%ebp), , have checked gdb equals n set in c code.

however, when try access first element in array, , move to, example %esi, value not 0 should be.

that using following code

movl 12(%ebp), %esi 

edit; of course fill array natural numbers before calling assembly function. did not want type in loop here.

as understands it, parentheses de-refrences first element of array, , copies esi, however, esi contains huge negative number when use info registers on breakpoint set after code in gdb.

so, how access arrays calloced beforehand, , passed assembly function? not possible derefrence, , copy single element?

here c function calls upon assembly function

int main(int argc, char *argv[]){      int n = 10;      int *array = calloc(n, sizeof(int));     int i, j;      // populate array n     for(i = 0; < n; i++){         array[i] = 2 + i;     }      printf("array: %d \n", sizeof(array));      // run sievs     sievs_assembly(n, array);      // print prime     print_prime(array, n);      // free mem     free(array);      return exit_success; } 

i dont want post assembly file whole, since school project, , i'm not asking solving assessment, specific problem. how derefrence array item.

the function prototype

extern void sievs_assembly(int n, int *a); 

i thought since pointer *a int array, , first argument n located @ 8(%ebp), first array element 12(%ebp).

how value if not enough movl 12(%ebp), %esi

when do:

movl 12(%ebp), %esi 

you have moved memory adress of array %esi. value of first element adress pointing to. can use:

movl (%esi), %eax 

this moves first element %eax. brackets basicly mean "what %esi pointing to". size of int 4 bytes (you check 'sizeof(int)'). acces next element use:

movl 4(%esi), %eax 

which moves next element %eax.

i've made example program prints 2 values array. note: made windows.

.macro print str         #macro name 'print'. 1 argument: 'str'     pushl \str           #argument names escaped     call _printf     addl $4, %esp        #pop arguments .endm  .macro printf str fs     #can't overload macro names, let's call 1 'printf'     pushl \str     pushl \fs            #printing numbers requires format srting     call _printf     addl $8, %esp .endm  .text .global _main  _main:                  #actual program, '_main' becomes 'winmain@16'     pushl %ebp          #push frame     movl %esp, %ebp      movl $array, %esi   #move array pointer $esi.      #print %esi pointing     printf (%esi), $fs      #print newline     print $nl      #print %esi+4 pointing to. since long 4 bytes     #the next element of array 4 bytes further first     printf 4(%esi), $fs      movl $0, %eax       #move 0 return register     leave               #pop frame     ret                 #return  .data  fs: .string "%i"    #format string nl: .string "\n"    #new line  array:              #some array     .long 1,2 

this program prints output:

1 2 

edit: since got attention, thought i'd update answer macros.

and explain _ prefixes on c library calls , main; i'm compiling on windows mingw, requires prefixes avoid getting undefined reference errors. on linux they're not needed.

for further documentation macros , gas see: using as