我试图等待来自UART的字符，然后传输回UART，我已经附加了.c文件，启动和链接器代码。我使用Qemu仿真LM 3S 811 ARM Cortex-M3板。但是我的qemu给出了以下错误。其实这是我对上一篇文章How to wait for characters from UART and transmit back on the UART in ARM Cortex -M3 emulated by Qemu的扩展
错误：

(qemu) qemu-system-arm: Trying to execute code outside RAM or ROM at 0xbf00e000
This usually means one of the following happened:

(1) You told QEMU to execute a kernel for the wrong machine type, and it crashed on startup (eg trying to run a raspberry pi kernel on a versatilepb QEMU machine)
(2) You didn't give QEMU a kernel or BIOS filename at all, and QEMU executed a ROM full of no-op instructions until it fell off the end
(3) Your guest kernel has a bug and crashed by jumping off into nowhere

main.c

#define  U0RBR (*((volatile unsigned char *) 0x4000C000))
#define  U0THR (*((volatile unsigned char *) 0x4000C000))
#define  U0LSR (*((volatile unsigned char *) 0x4000C004))

unsigned char UART0_RxChar(void);
void UART0_TxChar(char ch);

unsigned char UART0_RxChar(void) 
{
    while( (U0LSR & 0x01) == 0) {
        continue;
    }
    return U0RBR;
}

void UART0_TxChar(char ch) 
{
    U0THR = ch;
    while( (U0LSR & 0x40) == 0 ) {
        continue;
    }
}

int main(void)
{
    char receive;
    
    while(1) {
        receive = UART0_RxChar();
        UART0_TxChar(receive);
    }
    return 0;
}

startup.s

.global start
start:
.word 0x20001000
.word main

flash.ld

MEMORY
{
    FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x00010000
    SRAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x00002000
}

SECTIONS 
{
    .text : {
        *(.vectors);
        *(.text);
        etext = .;
    } > FLASH

    .rodata : {
        *(.rodata);
    } > FLASH

    .data : {
        sdata = .;
        *(.data);
        edata = .;
    } > SRAM AT > FLASH

    .bss : {
        sbss = .;
        *(.bss);
        ebss = .;
    } > SRAM
}

更新的代码

#define  UARTDR (*((volatile unsigned int *) 0x4000C000))
#define  UARTFR (*((volatile unsigned int *) 0x4000C018))

unsigned char UART0_RxChar(void);
void UART0_TxChar(char ch);

unsigned char UART0_RxChar(void) 
{
    while( (UARTFR & 0x01) == 0);
        return UARTDR;
}

void UART0_TxChar(char ch) 
{
    UARTDR = ch;
    while ( (UARTFR & 0x40) == 0);
}

int main(void)
{
    char receive;
    
    while(1) {
        receive = UART0_RxChar();
        UART0_TxChar(receive);
    }
    while(1) continue;  
}

输出：终端不允许我在终端中键入任何内容。