#include <stdio.h>
#include "wm_hal.h"

#define X_MAX 79
#define Y_MAX 25
uint8_t result[Y_MAX][X_MAX];

TIM_HandleTypeDef TimerDef;

void display_result(void)
{
	int x, y;
	const char c[] = "0123456789ABCDEF ";

	for (y = 0; y < Y_MAX; y++) {
		for (x = 0; x < X_MAX; x++) {
			putchar(c[result[y][x]]);
		}
		putchar('\n');
	}
}

void benchmark(void)
{
	int x, y, i;
	float a, b, ca, cb, t;

	for (y = -12; y <= 12; y++) {
		for (x = -39; x <= 39; x++) {
			a = ca = x * 0.0458;
			b = cb = y * 0.08333;

			for (i = 0; i <= 15; i++) {
				t = (a * a) - (b * b) + ca;
				b = (2 * a * b) + cb;
				a = t;

				if ((a * a + b * b) > 4)
					break;
			}
			result[y + 12][x + 39] = i;
		}
	}

	return;
}

void benchmark_main(uint32_t clk)
{
	uint32_t t, before, after;

	SystemClock_Config(clk);

	/* SystemClock_Config() enables SysTick interrupt */
	HAL_NVIC_DisableIRQ(SYS_TICK_IRQn);

	/* HAL_TIM_Base_Init() should be called after SystemClock_Config() */
	TimerDef.Instance = TIM0;
	TimerDef.Init.Unit = TIM_UNIT_US;
	TimerDef.Init.Period = ~0; // 0 <= TIM0_CNT <= TimerDef.Init.Period
	TimerDef.Init.AutoReload = TIM_AUTORELOAD_PRELOAD_ENABLE;
	if (HAL_TIM_Base_Init(&TimerDef) == HAL_OK)
		HAL_TIM_Base_Start(&TimerDef);

	t = before = TIM->TIM0_CNT;
	while ((before = TIM->TIM0_CNT) == t);
	benchmark();
	after = TIM->TIM0_CNT;

	/* HAL_TIM_Base_Stop/DeInit is required to restart timer next time */
	HAL_TIM_Base_Stop(&TimerDef);
	HAL_TIM_Base_DeInit(&TimerDef);

	printf("%ld: %lu - %lu = %lu\n", clk, after, before, after - before);
}

int main(void)
{
	printf("enter main\n");

	/* PLL is 480MHz, CPU clock should be multiply of APB clock (40MHz) */
	benchmark_main(2);	// CPU_CLK_240M
	benchmark_main(3);	// CPU_CLK_160M
	benchmark_main(4);	// 120MHz (secret?)	
	benchmark_main(6);	// CPU_CLK_80M
	benchmark_main(12);	// CPU_CLK_40M
		
	display_result();

	printf("exit main\n");

	while (1);
}

/* called from wm_tim.c:HAL_TIM_Base_Init() */
void HAL_TIM_Base_MspInit(TIM_HandleTypeDef *htim_base)
{
	__HAL_RCC_TIM_CLK_ENABLE();
}

/* called from wm_tim.c:HAL_TIM_Base_DeInit() */
void HAL_TIM_BASE_MspDeInit(TIM_HandleTypeDef *htim_base)
{
	__HAL_RCC_TIM_CLK_DISABLE();
}

/* SystemClock_Config() requires this handler, do not forget -mistack */
__attribute__((isr)) void CORET_IRQHandler(void)
{
	(void)*(volatile unsigned int *)0xe000e010;

	HAL_IncTick();
}