My paint() in C

Hi, I wrote the follow code for creare the PAINT BASIC with C:

void paint(unsigned char x, unsigned char y, char c)
{
  __asm
       pop hl
	     pop bc
	     pop de
	     dec sp
	     pop af
	     push af
	     inc sp
	     push de
	     push bc
	     push hl
	     push af
       ld h, 4(ix)
       ld l, 5(ix)
       call #0x0069    ; ---> BIOS call for color the screen
       ld 6(ix),#0x9D
	     call #0x0069
  __endasm;
}

my app.c is the follow:

#include "graphic.h"


extern int x, y, a, b, ray, col;

void (*function)() = (void (*)())0xc0;




void main()
{
  color(5,15,5);
  screen(5);
  paint(100,100,6);
  a=100;
  b=100;
  ray=50;
  col=2;
  circle();
  while(1){};
}

If I compile the project I can see a circle but that it hasn't been colored with my paint().
I researched in the web how to create my paint with the right register and call but it doesn't work. Why?