#include #include "priv_gpio.h" #include void user_delay(uint32_t ms) { register uint32_t r1 asm("r1") = ms; asm("\ mov r0, 0; \ mov r1, %0; \ svc 2; \ " :: "r" (r1)); } int fork(void) { int result; asm("\ mov r0, sp; \ svc 3; \ mov %0, r0; \ " : "=r" (result)); return result; } void user_main(void) { gpio(GPIO_MODE, 5, OUTPUT); if (fork() == 0) { while (1) { gpio(GPIO_OUT, 5, 1); user_delay(1000); } } else { while (1) { gpio(GPIO_OUT, 5, 0); user_delay(500); } } }