【ARM】在Uboot中运行第一个汇编程序

00. 目录

01. 汇编程序

汇编程序

    .section .rodata
    .align 2
.LC0:
    .string "hello arm\n"


    .section .text
    .align 2
    .global _start
_start:
    stmfd sp!, {lr}

    ldr r0, =.LC0
    mov lr, pc
	@uboot中printf的地址
    ldr pc, =0x43e11a2c


    ldmfd sp!, {pc}

0x43e11a2c地址的获取

查看System.map文件

[root@itcast uboot_tiny4412-master]# cat System.map | grep printf
43e1188c T serial_printf
43e11978 T fprintf
43e11a2c T printf
43e11a70 T vprintf
43e26b74 T vsprintf
43e271ac T sprintf
[root@itcast uboot_tiny4412-master]# 

02. 编译

编译生成二进制文件

# 第一步：生成目标文件
[root@itcast 8th]# arm-linux-gcc -c 1hello.s -o 1hello.o

# 第二步：链接 生成可执行文件
[root@itcast 8th]# arm-linux-ld -Ttext=0x40008000 1hello.o -o 1hello

# 第三步：生成不带头信息的二进制文件
[root@itcast 8th]# arm-linux-objcopy -O binary 1hello 1hello.bin
[root@itcast 8th]# 

03. 下载执行

在minicom端

DengJin # dnw 70000000
OTG cable Connected!
Now, Waiting for DNW to transmit data
Download Done!! Download Address: 0x70000000, Download Filesize:0x28
Checksum is being calculated.
Checksum Value => MEM:fb3 DNW:1083
Checksum failed.

DengJin # 

在PC端

# 将bin文件通过dnw下载到开发板
[root@itcast 8th]# dnw 1hello.bin 
load address: 0x57E00000
Writing data...
100%	0x00000032 bytes (0 K)
speed: 0.000076M/S
[root@itcast 8th]# 

执行

DengJin # go 70000000
## Starting application at 0x70000000 ...
hello arm
## Application terminated, rc = 0xA
DengJin # 

04. 文件对比

[root@itcast 8th]# file 1hello.bin  
1hello.bin: data

[root@itcast 8th]# file 1hello
1hello: ELF 32-bit LSB executable, ARM, version 1 (SYSV), statically linked, not stripped

[root@itcast 8th]# ls -l 1hello 1hello.bin  
-rwxr-xr-x. 1 root root 33565 8月   4 10:34 1hello
-rwxr-xr-x. 1 root root    40 8月   4 10:42 1hello.bin
[root@itcast 8th]# 

05. 程序示例二

汇编程序

    .section .rodata
    .align 2
.LC0:
    .string "hello arm\n"


    .section .text
    .align 2
    .global _start
_start:
    stmfd sp!, {lr}

    ldr r0, =.LC0 
    mov lr, pc
    ldr pc, =0x43e11a2c


    mov r4, #'a'
1:
    mov r0, r4
    mov lr, pc
    ldr pc, =0x43e119f4

    add r4, #1
    cmp r4, #'z'
    ble 1b

    mov r0, #'\n'
    mov lr, pc
    ldr pc, =0x43e119f4

    ldmfd sp!, {pc}

编译生成二进制文件

[root@itcast 2main]# arm-linux-gcc -c main.s 
[root@itcast 2main]# arm-linux-ld -Ttext=0x40008000 main.o -o main 
[root@itcast 2main]# arm-linux-objcopy -O binary main main.bin 

执行结果

DengJin # go 40008000
## Starting application at 0x40008000 ...
hello arm
abcdefghijklmnopqrstuvwxyz
## Application terminated, rc = 0xD
DengJin # 

06. 附录