一步步写嵌入式操作系统 linux平台实现代码
step 0 准备开发环境 1 安装交叉编译工具 sudo apt-get install gcc-arm-none-eabi sudo apt-get install gcc-arm-linux-gnueabihf sudo apt-get install g++-arm-linux-gnueabihf
2 手边编译skyeye 用apt命令安装的skyeye模拟器版本（1.2.5）有bug,需要手动编译更高版本的skyeye
下载并解压skyeye 1.2.6_rc1的代码，
~/Downloads/skyeye-1.2.6_rc1
根据执行skyeye-1.2.6_rc1/INSTALL的说明
1 执行 ./configure
2 执行 make 后
编译错误1：
In file included from /usr/include/fcntl.h:289:0,
from nandflash/nandflash_smallblock.c:19:
In function ‘open’,
inlined from ‘nandflash_sb_setup’ at nandflash/nandflash_smallblock.c:519:24:
/usr/include/x86_64-linux-gnu/bits/fcntl2.h:50:4: error: call to ‘__open_missing_mode’ declared with attribute error: open with O_CREAT or O_TMPFILE in second argument needs 3 arguments
__open_missing_mode ();
解决方法： 修改skyeye-1.2.6_rc1/device/nandflash/nandflash_smallblock.c 519行 if ((nf->fdump= open(dev->dump, FILE_FLAG)) < 0) 改为： if ((nf->fdump= open(dev->dump, FILE_FLAG, 0777)) < 0)
编译错误2：
gcc -g -O2 -o skyeye skyeye.o ./utils/libutils.a ./arch/arm/libarm.a ./device/libdev.a ./arch/mips/libmips.a ./arch/ppc/libppc.a ./arch/bfin/libbfin.a ./arch/mips/libmips.a ./arch/coldfire/libcoldfire.a -lc ./utils/libutils.a -lbfd -lm -lc
./arch/mips/libmips.a(decoder.o)：在函数‘decode’中：
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1079：对‘sign_extend_UInt32’未定义的引用
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1105：对‘sign_extend_UInt32’未定义的引用
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1049：对‘sign_extend_UInt32’未定义的引用
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1027：对‘sign_extend_UInt32’未定义的引用
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1013：对‘sign_extend_UInt32’未定义的引用
./arch/mips/libmips.a(decoder.o):/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:1001: 跟着更多未定义的参考到 sign_extend_UInt32
./arch/mips/libmips.a(decoder.o)：在函数‘decode’中：
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:240：对‘divide_UInt32’未定义的引用
/home/kolya/Downloads/skyeye-1.2.6_rc1/arch/mips/common/decoder.c:231：对‘divide_Int32’未定义的引用
collect2: error: ld returned 1 exit status
Makefile:305: recipe for target 'skyeye' failed
make[2]: *** [skyeye] Error 1
make[2]: Leaving directory '/home/kolya/Downloads/skyeye-1.2.6_rc1'
Makefile:351: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/kolya/Downloads/skyeye-1.2.6_rc1'
Makefile:227: recipe for target 'all' failed
解决方法：
修改skyeye-1.2.6_rc1/arch/mips/common/decoder.c文件：
添加函数
UInt32 sign_extend_UInt32(UInt32 x, int s)
{
return x + s;
}
skyeye-1.2.6_rc1/arch/mips/common/decoder.c:231行 注释掉divide_Int32(x, y); skyeye-1.2.6_rc1/arch/mips/common/decoder.c:240行 注释掉divide_UInt32(x, y);
编译错误3：
checking for C++ compiler default output file name...
configure: error: C++ compiler cannot create executables
See `config.log' for more details.
解决方法:安装g++
编译错误4：
checking for gcc... configure: error: **** gcc < 3.0 !!!
解决方法:
在configure文件中有:
case `$gcc_exec -dumpversion | sed -e 's,\..*,.,' -e q` in
3.*)
;;
[456789].*)
dbct=false
;;
*)
{ { echo "$as_me:$LINENO: error: **** gcc < 3.0 !!!" >&5
echo "$as_me: error: **** gcc < 3.0 !!!" >&2;}
{ (exit 1); exit 1; }; }
;;
esac
gcc版本为7.3.0, 但执行gcc -dumpversion输出为7 说明这里把gcc的版本误判为了小于3. 解决方法为case判断中添加对7的处理逻辑
case `$gcc_exec -dumpversion | sed -e 's,\..*,.,' -e q` in
3.*)
;;
7)
dbct=false
;;
[456789].*)
dbct=false
;;
*)
{ { echo "$as_me:$LINENO: error: **** gcc < 3.0 !!!" >&5
echo "$as_me: error: **** gcc < 3.0 !!!" >&2;}
{ (exit 1); exit 1; }; }
;;
esac
之后重新make即可编译出skyeye