我只是想编译一些我从书中输入的简单示例代码,GCC给出了上述错误.这是我的代码:
$cat -n test.cpp
1 #define READ_COMMAND 3
2
3 #define MSG_LENGTH 128
4
5 #include dio.h>
7
8 int main(int argc,char *arg[])
9 {
10 int syslog_command = READ_COMMAND;
11 int bytes_to_read = MSG_LENGTH;
12 int retval;
13 char buffer[MSG_LENGTH];
14
15 asm volatile(
16 "movl %1,%%ebx\n\t"
17 "movl %2,%%ecx\n\t"
18 "movl %3,%%edx\n\t"
19 "movl $103,%%eax\n\t"
20 "int $128\n\t"
21 "movl %%eax,%0"
22 :"=r" (retval)
23 :"m"(syslog_command),"r"(buffer),"m"(bytes_to_read)
24 :"%eax","%ebx","%ecx","%edx");
25 if (retval > 0) printf("%s\n",buffer);
26
27 }
28
29
代码应该调用syslog()系统调用来从内核printk()环形缓冲区读取最后128个字节.以下是有关我的操作系统和系统配置的一些信息:
uname -a:
Linux 3.2.0-26-generic #41-Ubuntu SMP Thu Jun 14 17:49:24 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
gcc -v:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v –with-pkgversion=’Ubuntu/Linaro 4.6.3-1ubuntu5′ –with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs –enable-languages=c,c++,fortran,objc,obj-c++ –prefix=/usr –program-suffix=-4.6 –enable-shared –enable-linker-build-id –with-system-zlib –libexecdir=/usr/lib –without-included-gettext –enable-threads=posix –with-gxx-include-dir=/usr/include/c++/4.6 –libdir=/usr/lib –enable-nls –with-sysroot=/ –enable-clocale=gnu –enable-libstdcxx-debug –enable-libstdcxx-time=yes –enable-gnu-unique-object –enable-plugin –enable-objc-gc –disable-werror –with-arch-32=i686 –with-tune=generic –enable-checking=release –build=x86_64-linux-gnu –host=x86_64-linux-gnu –target=x86_64-linux-gnu
Thread model: posix
gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5)
下面是完整的错误:
$gcc test.cpp
test.cpp: Assembler messages:
test.cpp:25: Error: unsupported for `mov'