我沒有使用arm-elf-gdb 使用gdb替代，也可以用，

目前skyeye－1.2.9暫時不支援gdb除錯，但是1.2.8及以前版本是支援的，因此本文以1.2.8為例說明
要使用SkeyEye除錯功能，可以在執行的時候加入-d引數，例如：
$skyeye -e hello -d
skyeye會提示
debugmode= 1, filename = skyeye.conf, server TCP port is 12345
這時就在本機的12345埠開啟了gdb服務
這時在當前目錄重新開一個終端程式
$arm-elf-gdb hello
(gdb) target remote 127.0.0.1:12345
Remote debugging using 127.0.0.1:12345 
hello () at hello.c:23
23        }
(gdb)
同時原skeyeye段給出提示
Remote debugging using host:12345
這就說明已經連線上服務，可以開始除錯了




(gdb) help                   #－－獲取幫助資訊，呵呵，這個最重要了
List of classes of commands:

aliases -- Aliases of other commands
breakpoints -- Making program stop at certain points
data -- Examining data
files -- Specifying and examining files
internals -- Maintenance commands
obscure -- Obscure features
running -- Running the program
stack -- Examining the stack
status -- Status inquiries
support -- Support facilities
tracepoints -- Tracing of program execution without stopping the program
user-defined -- User-defined commands

Type "help" followed by a class name for a list of commands in that class.
Type "help all" for the list of all commands.
Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.

下面列出常用的除錯指令：

list ---列出原始碼

如果連續輸入，則會依次列出原始碼
如果想看23行的上下文，可以使用list 23



單步執行
step 進入子函式的單步－－如果在子函式中想要退出該子函式，可以使用finish命令
next 不進入子函式的單步


檢視變數
print
(gdb) print hellostr   －－ 檢視字串
$2 = 0x1000078 "helloworld"
(gdb) print timeout    －－檢視int變數
$3 = 1
(gdb) print hello       －－檢視函式資訊
$4 = {void (void)} 0x1000020 <hello>


修改變數的值
1。顯示變數型別
(gdb) ptype timeout
type = int
(gdb) whatis timeout
type = int
2。修改變數的值
(gdb) print timeout
$5 = 2
(gdb) set timeout=5
(gdb) print timeout
$6 = 5




設定斷點

break
1。break 行數
(gdb) b 18
Breakpoint 4 at 0x1000048: file hello.c, line 18.
2。函式斷點
(gdb) break hello
Breakpoint 2 at 0x100002c: file hello.c, line 13.
3。條件斷點
(gdb) break if timeout=3
Breakpoint 1 at 0x1000044: file hello.c, line 17.
檢視斷點資訊
(gdb) info b
Num     Type           Disp Enb Address    What
1       breakpoint     keep y   0x01000044 in hello at hello.c:17
    stop only if timeout=3
2       breakpoint     keep y   0x0100002c in hello at hello.c:13
3       breakpoint     keep y   0x01000044 in hello at hello.c:17
4       breakpoint     keep y   0x01000048 in hello at hello.c:18


監視變數的值
watch 變數名   當變數的值發生變化時，程式會中斷執行
(gdb) watch timeout
Watchpoint 5: timeout
例如，設定檢測timeout後，繼續執行到while(++timeout != BOGO_MIPS);單步執行
(gdb) s
Watchpoint 5: timeout

Old value = 1
New value = 2
0x0100004c in hello () at hello.c:18
18            while(++timeout != BOGO_MIPS);
GDB會中斷程式，並將變數的變化顯示出來
檢視監測資訊：
使用info watch 檢視
(gdb) info watch
Num     Type           Disp Enb Address    What
5       watchpoint     keep y              timeout
    breakpoint already hit 1 time
可見監測點也是斷點的一種


斷點的管理
1。檢視斷點資訊
Num     Type           Disp Enb Address    What
5       watchpoint     keep y              timeout
    breakpoint already hit 1 time
6       breakpoint     keep y   0x0100002c in hello at hello.c:13
7       breakpoint     keep y   0x01000048 in hello at hello.c:18
8       breakpoint     keep y   0x0100004c in hello at hello.c:18
    stop only if timeout=4

2。刪除斷點
如果要刪除所有斷點，可使用
(gdb) delete breakpoints
刪除所有斷點嗎？ (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
如果要刪除某一個斷點，可使用
(gdb) delete breakpoints 6
(gdb) info b
Num     Type           Disp Enb Address    What
5       watchpoint     keep y              timeout
    breakpoint already hit 1 time
7       breakpoint     keep y   0x01000048 in hello at hello.c:18
8       breakpoint     keep y   0x0100004c in hello at hello.c:18
    stop only if timeout=4

3。禁止某個斷點
(gdb) info b
Num     Type           Disp Enb Address    What
5       watchpoint     keep y              timeout
    breakpoint already hit 1 time
7       breakpoint     keep y   0x01000048 in hello at hello.c:18
8       breakpoint     keep y   0x0100004c in hello at hello.c:18
    stop only if timeout=4
(gdb) disable b 5
(gdb) info b
Num     Type           Disp Enb Address    What
5       watchpoint     keep n              timeout
    breakpoint already hit 1 time
7       breakpoint     keep y   0x01000048 in hello at hello.c:18
8       breakpoint     keep y   0x0100004c in hello at hello.c:18
    stop only if timeout=4
(gdb)
4。允許斷點
(gdb) enable b 5
(gdb) info b
Num     Type           Disp Enb Address    What
5       watchpoint     keep y              timeout
    breakpoint already hit 1 time
7       breakpoint     keep y   0x01000048 in hello at hello.c:18
8       breakpoint     keep y   0x0100004c in hello at hello.c:18
    stop only if timeout=4
(gdb)