you want to move your stuff by a certain amount of pixels over a certain amount of time, the same on old computers as on faster computers.
well try something like this.
float deltaTime = 0.0f;
int currentTime = 0;
int lastTime = 0;
// main game loop
currentTime = SDL_GetTicks();
deltaTime = (float)(currentTime - lastTime) / 1000;
lastTime = currentTime;
// assume we have this sprite to move
// both position and speed vars are floats
player.x += player.speedX * deltaTime;
player.y += player.speedY * deltaTime;
// call it to be drawn using a fictional