10 printf 触发 undefined instruction 异常

发布于 2022-02-28 11:08:45 浏览：1358 订阅该版

各位大佬好，打扰了。最近在 zynq7020 上测试发现，在启用 libc posix 后，尝试使用 ``printf``, 发现打印 int 参数会导致 `undefined instruction`. 请问可能是什么原因, 谢谢.
----

测试代码:
```C
#include <stdio.h>
int test_libc(int argc, char **argv)
{
    int i = 12;
    printf("hello libc %d\n", i);
    return 0;
}
MSH_CMD_EXPORT(test_libc, test libc);
```
---
结果:
```SHELL
msh />
msh />test_libc
undefined instruction:
Execption:
r00:0x0013e520 r01:0x0014a02c r02:0x00137378 r03:0x0014b95c
r04:0x0014b95c r05:0xdeadbeef r06:0xdeadbeef r07:0xdeadbeef
r08:0xdeadbeef r09:0xdeadbeef r10:0xdeadbeef
fp :0x0014b97c ip :0x0014a77e
sp :0x0014b924 lr :0x00132609 pc :0x00133388
cpsr:0x20000033
thread           pri  status      sp     stack size max used left tick  error
---------------- ---  ------- ---------- ----------  ------  ---------- ---
tshell            20  running 0x00000184 0x00001000    09%   0x00000009 000
ulog_async        30  suspend 0x000000ac 0x00000400    25%   0x00000013 000
tidle0            31  ready   0x00000060 0x00000200    22%   0x00000004 000
main              10  suspend 0x000000bc 0x00000800    28%   0x00000011 000
shutdown...
(0) assertion failed at function:rt_hw_cpu_shutdown, line number:85 
```
---
根据 pc objdup 定位到的代码
```

00133380 <_vfprintf_r>:
  133380:	e92d 4ff0 	stmdb	sp!, {r4, r5, r6, r7, r8, r9, sl, fp, lr}
  133384:	461c      	mov	r4, r3
  133386:	ed2d 8b04 	vpush	{d8-d9}
  13338a:	4688      	mov	r8, r1
  13338c:	4693      	mov	fp, r2
  13338e:	4605      	mov	r5, r0
  133390:	b0bd      	sub	sp, #244	; 0xf4
  133392:	9005      	str	r0, [sp, #20]
```
---
编译参数
``` PYTHON
DEVICE = ' -Wall -mcpu=cortex-a9 -mfpu=vfpv3 -ffunction-sections -fdata-sections -ftree-vectorize -munaligned-access -ffast-math -mfloat-abi=hard'
    CFLAGS = DEVICE
    AFLAGS = ' -c -fmessage-length=0' + DEVICE + ' -x assembler-with-cpp -D__ASSEMBLY__ -I. '
    LINK_SCRIPT = 'lscript.ld'
    LFLAGS = DEVICE + ' -Wl,-Map=zynq7000.map,--gc-sections,-build-id=none -specs=Xilinx.spec -Wl,-T -Wl,%s' % LINK_SCRIPT
    
```