Differences Between 51, STM32, and Linux LED Control

#include <reg51.h>
sbit LED = P1^0;
void main(){ LED = 0;
 while(1);}

#include "stm32f4xx.h"
/* Main function*/
int main(void){
 /* Enable GPIOH clock; when using peripherals, you must first enable its clock*/
 RCC_AHB1ENR |= (1<<7);
 /* LED port initialization */
 /*GPIOH MODER10 clear*/
 GPIOH_MODER &= ~(0x03<< (2*10));
 /*PH10 MODER10 = 01b output mode*/
 GPIOH_MODER |= (1<<2*10);
 /*GPIOH OTYPER10 clear*/
 GPIOH_OTYPER &= ~(1<<1*10);
 /*PH10 OTYPER10 = 0b push-pull mode*/
 GPIOH_OTYPER |= (0<<1*10);
 /*GPIOH OSPEEDR10 clear*/
 GPIOH_OSPEEDR &= ~(0x03<<2*10);
 /*PH10 OSPEEDR10 = 0b speed 2MHz*/
 GPIOH_OSPEEDR |= (0<<2*10);
 /*GPIOH PUPDR10 clear*/
 GPIOH_PUPDR &= ~(0x03<<2*10);
 /*PH10 PUPDR10 = 01b pull-up mode*/
 GPIOH_PUPDR |= (1<<2*10);
 /*PH10 BSRR register's BR10 set to 1, output low level*/
 GPIOH_BSRR |= (1<<16<<10);  // LED On
 while (1);}

#include "stm32f10x.h"
/* LED clock port, pin definition*/
#define LED_PORT       GPIOC
#define LED_PIN       GPIO_Pin_0
#define LED_PORT_RCC            RCC_APB2Periph_GPIOC
void LED_Init(){
 GPIO_InitTypeDef GPIO_InitStructure;        // Define structure variable
 RCC_APB2PeriphClockCmd(LED_PORT_RCC, ENABLE);
 GPIO_InitStructure.GPIO_Pin = LED_PIN;                // Select the IO port to set
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;      // Set push-pull output mode
 GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;       // Set transmission speed
 GPIO_Init(LED_PORT,&GPIO_InitStructure);              // Initialize GPIO 
 GPIO_SetBits(LED_PORT, LED_PIN);                       // Pull LED port high to turn off LED}
int main(){
 LED_Init();  GPIO_ResetBits(LED_PORT,GPIO_Pin_0);// LED On
 while(1);}

#include <wiringPi.h>
int main(void){
 wiringPiSetup();
 pinMode(7, OUTPUT);
 digitalWrite(7, HIGH);
 while(1);}

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/ioctl.h>
#include <linux/gpio.h>
#include <mach/regs-gpio.h>
#include "led.h"
static int led_open(struct inode *inode, struct file *file){
 s3c2410_gpio_cfgpin(S3C2410_GPB(5), S3C2410_GPIO_OUTPUT);
 s3c2410_gpio_setpin(S3C2410_GPB(5), 1);
 return 0;}
static int led_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg){
 switch (cmd) {
 case LED_ON:
 s3c2410_gpio_setpin(S3C2410_GPB(5), 0);
 return 0;
 case LED_OFF:
 s3c2410_gpio_setpin(S3C2410_GPB(5), 1);
 return 0;
 default:
 return -EINVAL;
 }}
static struct file_operations led_fops = {
 .owner = THIS_MODULE,
 .open = led_open,
 .ioctl = led_ioctl,
};
static struct miscdevice led_misc = {
 .minor = MISC_DYNAMIC_MINOR,
 .name = "led",
 .fops = &led_fops,
};
static int led_init(void){
 return misc_register(&led_misc);}
static void led_exit(void){
 misc_deregister(&led_misc);
}
MODULE_LICENSE("Dual BSD/GPL");
module_init(led_init);
module_exit(led_exit);

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <stdio.h>
#include "led.h"
int main(void){
 int fd;
 fd = open("/dev/led", O_RDWR);
 if (fd < 0) {
 printf("No such device!\n");
 return -1;
 }
 while (1) {
 ioctl(fd, LED_ON);
 sleep(1);
 ioctl(fd, LED_OFF);
 sleep(1);
 }
 close(fd);
 return 0;}