Minimizing Interrupt Time, Maximizing Compiler Processing Speed, Reaching STM32F3 Operator Speed - c

Question

I am currently working on STM32F3 Discovery Board. I wrote a basic program in C to see if it works at 72 MHz which is about 14 ns in time. Hopefully it worked at this frequency, but when I want to toggle just one random pin on the device, turning it ON or OFF takes 660 ns in an infinite while loop. Then I checked with an oscilloscope, how much each command takes. Values might not be exact, Here is what I found;
a while loop(only for checking) = 120 ns, a "for" loop(only for checking) = 160 ns
One turn of a while loop = 280 ns, one turn of a for loop = 320 ns, which means each turn takes 160 ns.
asm("NOP") = 14 ns(which must be equal to operator frequency(72 MHz, as expected), an empty function call = 225 ns
I don't think these values are same for other compilers, or other computers, but I am not even close to 72 MHz. Minimum interrupt I got was 2 microsecond. Is there any way to minimize these values? Is there anyway to increase the gcc compiler speed?
#include "stm32f30x.h"
#include <common.h>
void InitializeTimer(void) ;
void EnableTimerInterrupt(void);
void TIM2_IRQHandler(void);
GPIO_InitTypeDef configuration;
void dly(int dly_nmbr);
int main(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
//NVIC_InitTypeDef NVIC_InitStructure;
RCC_ClocksTypeDef RCC_ClockFreq;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* Configure PA10 in output pushpull mode */
/*****I called init_pin function from common.c because it was easier
but I guess it takes some time too*********/
init_pin(GPIOA,GPIO_Pin_10,GPIO_Mode_OUT,GPIO_Speed_50MHz,GPIO_OType_PP,GPIO_PuPd_NOPULL);
/****I tried usual way to configure the pins too****/
//configuration.GPIO_Pin = GPIO_Pin_10;
//configuration.GPIO_Mode = GPIO_Mode_OUT;
//configuration.GPIO_OType = GPIO_OType_PP;
//configuration.GPIO_Speed = GPIO_Speed_50MHz;
//configuration.GPIO_PuPd = GPIO_PuPd_NOPULL;
//GPIO_Init(GPIOA, &configuration);
//InitializeTimer();
/*** This function fills the RCC_ClockFreq structure with the current
frequencies of different on chip clocks (for debug purpose) **************/
RCC_GetClocksFreq(&RCC_ClockFreq);
/* Enable Clock Security System(CSS): this will generate an NMI exception
when HSE clock fails *****************************************************/
RCC_ClockSecuritySystemCmd(ENABLE);
/* Enable and configure RCC global IRQ channel, will be used to manage HSE ready
and PLL ready interrupts.
These interrupts are enabled in stm32f0xx_it.c file **********************/
/* I disabled the interrupts for the purpose of maximizing the program speed*/
// NVIC_InitStructure.NVIC_IRQChannel = RCC_IRQn;
// NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
// NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
// NVIC_Init(&NVIC_InitStructure);
/************* Output HSE clock on MCO1 pin(PA8) ************/
/****************** Enable the GPIOA Clock ******************/
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* MCO pin configuration: PA8 */
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Output System Clock on MCO pin */
RCC_MCOConfig(RCC_MCOSource_SYSCLK);
/************** This is the toggling part. I tried each command here ***************/
while(1)
{
// volatile int i = 0;
// dly(0);
/*I called an empty function called dly before and after the toggle
to see function call time*/
GPIO_Toggle(GPIOA,GPIO_Pin_10);
// dly(0);
// while(i<=0)
// {
// i++;
// }
// for(i=0;i<=0;i++);
}
}
/*Empty Function*/
void dly(int dly_nmbr)
{
}
/************** Interrupt Functions **************/
// void TIM2_IRQHandler()
// {
// if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
// {
// TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
// }
// }
// void InitializeTimer()
// {
// RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
//
// TIM_TimeBaseInitTypeDef timerInitStructure;
// timerInitStructure.TIM_Prescaler = 0;
// timerInitStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned2;
// timerInitStructure.TIM_Period = 2;
// timerInitStructure.TIM_ClockDivision = 0x0000;
// timerInitStructure.TIM_RepetitionCounter = 100;
// TIM_TimeBaseInit(TIM2, &timerInitStructure);
//
// TIM_Cmd(TIM2, ENABLE);
// TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
// EnableTimerInterrupt();
// }
// void EnableTimerInterrupt()
// {
// NVIC_InitTypeDef nvicStructure;
// nvicStructure.NVIC_IRQChannel = TIM2_IRQn;
// nvicStructure.NVIC_IRQChannelCmd = ENABLE;
// // TIM2->ARR = 1;
// // TIM2->PSC = 1;
// NVIC_Init(&nvicStructure);
//
// }
/****************** EOF ********************/