qemu 模拟stm32f103RB uart && system tick

QEMU emulator version 5.1.0

stm32 code:

#include <stdio.h>               
#include <stm32f10x.h>           

#include <string.h>   

extern void SER_Init(void);    

static __IO uint32_t TimingDelay;
void Delay(__IO uint32_t nTime)
{ 
   TimingDelay = nTime;
   while(TimingDelay != 0);
}

void SysTick_Handler( void )   
{   
    if( TimingDelay != 0x00 ){ 
        TimingDelay--;
    }
}

int init_system_tick( void )
{
    printf( "SystemCoreClock = %d\n", SystemCoreClock );
    if( SysTick_Config(SystemCoreClock / 1000) ){
        printf("SysTick_Config fail!!!\n");