netbeans c/c++ (or gcc) & nasm co-work

1. assemble asm to obj

run: nasm -felf64 maxofthree.asm will generate maxofthree.o

2.

run: ar -r libmyasm.a maxofthree.o generate libmyasm.a (if use gcc, not Netbeans, this step is not needed.)

3.

Netbeans:

right-click project->properties->Build->Linker->Libraries->Add Library File(Not "Add Library"), Select File type "Static Library(.a)", add libmyasm.a.

(If use gcc, run: gcc maxofthree.o callmaxofthree.c will generate a.out, run it : ./a.out)

Now , it works!!!

; -----------------------------------------------------------------------------
; A 64-bit function that returns the maximum value of its three 64-bit integer
; arguments.The function has signature:
;
;int64_t maxofthree(int64_t x, int64_t y, int64_t z)
;
; Note that the parameters have already been passed in rdi, rsi, and rdx.
; We just have to return the value in rax.
; -----------------------------------------------------------------------------

global maxofthree
section .text

maxofthree:
mov rax, rdi ; result (rax) initially holds x
cmp rax, rsi ; is x less than y?
cmovl rax, rsi ; if so, set result to y

cmp rax, rdx ; is max(x,y) less than z?
cmovl rax, rdx  ; if so, set result to z
ret ; the max will be in rax

/*
* A small program that illustrates how to call the maxofthree function we wrote in
* assembly language.
*/
#include <stdio.h>
#include <inttypes.h>
#include <sys/time.h>

int64_t maxofthree(int64_t, int64_t, int64_t);

int64_t maxofthree_c(int64_t a, int64_t b, int64_t c)
{
int64_t tmp = (a > b ? a : b);
return (tmp > c ? tmp : c);
}

static int count = 100000000;
static int64_t a = -10330000000, b = 2003000033, c = 100000003330000;

void asm_fun()
{
struct  timeval  start;
struct  timeval  end;
unsigned long timer;
int i = 0;
gettimeofday(&start,NULL);
for( i = 0; i < count; i++)
{
maxofthree(a, b, c);
}
gettimeofday(&end,NULL);
timer = 1000000 * (end.tv_sec-start.tv_sec)+ end.tv_usec-start.tv_usec;
printf("comparing %d times (assembly) costs %ld us\n", count, timer);
}
void c_fun()
{
struct  timeval  start;
struct  timeval  end;
unsigned long timer;
int i = 0;
gettimeofday(&start,NULL);
for(i = 0; i < count; i++)
{
maxofthree_c(a + i, b - i, c + i);
}
gettimeofday(&end,NULL);
timer = 1000000 * (end.tv_sec-start.tv_sec)+ end.tv_usec-start.tv_usec;
printf("comparing %d times (c) costs %ld us\n", count, timer);
}
int main()
{
asm_fun();
c_fun();
asm_fun();
c_fun();
return 0;
}