关于使用Makefile进行GCC编译报错问题解决方法

汇编代码如下：

_start:        ldr r0, =0x11111111        ldr r1, =0xE0200240        str r0, [r1]        ldr r0, =0x0        ldr r1, =0xE0200244        str r0, [r1]flag:        b flag

Makefile代码如下：

led.bin: start.o        arm-linux-ld -Ttext 0x0 -o led.elf $^        arm-linux-objcopy -O binary led.elf led.bin        arm-linux-objdump -D led.elf > led_elf.dis        gcc mkv210_image.c -o mkx210        ./mkx210 led.bin 210.bin%.o : %.S        arm-linux-gcc -o $@ $< -c%.o : %.c        arm-linux-gcc -o $@ $< -c clean:        rm *.o *.elf *.bin *.dis mkx210 -f

进行make，但是报错，如下：

as   -o start.o start.sstart.s: Assembler messages:start.s:2: Error: no such instruction: `ldr r0,=0x11111111'start.s:3: Error: no such instruction: `ldr r1,=0xE0200240'start.s:4: Error: invalid char '[' beginning operand 2 `[r1]'start.s:6: Error: no such instruction: `ldr r0,=0x0'start.s:7: Error: no such instruction: `ldr r1,=0xE0200244'start.s:8: Error: invalid char '[' beginning operand 2 `[r1]'start.s:10: Error: no such instruction: `b flag'make: *** [start.o] Error 1

是什么原因呢？
Makefile中的依赖也没有写错，汇编也没有错，为什么编译不了而报错呢？原因很傻瓜，就是因为start.s写错了，后缀名要大写，写成：start.S，就可以编译成功了。

arm-linux-gcc -o start.o start.S -carm-linux-ld -Ttext 0x0 -o led.elf start.oarm-linux-ld: warning: cannot find entry symbol _start; defaulting to 00000000arm-linux-objcopy -O binary led.elf led.binarm-linux-objdump -D led.elf > led_elf.disgcc mkv210_image.c -o mkx210./mkx210 led.bin 210.bin