一个小小的GAS汇编问题！～

[C_program_Baby]

1 # gas command test
2 .section .data
3 value:
4 .int 1, 2, 3, 4, 5, 6
5 valu:
6 .quad 1, 2, 3, 4, 5, 6
7 .section .bss
8 .lcomm buffer,100
9 .section .text
10 .equ LINUX, 5
11 .globl _start
12 _start:
13 nop
14 pushl $0
15 call exit
16
~
我用GDB调试后 x /6gd &valu 它说没有定义valu这个符号 这是怎么回事？

[用户 昵称]

valu已经变成了数值了吧。

[独孤过儿]

[root@cv0005759d1 stack]# vim love.s 

#gas command test
.section    .data
value:
    .int    1, 2, 3, 4, 5, 6
valu:
    .quad   1, 2, 3, 4, 5, 6
.section    .bss
    .lcomm  buffer, 100
.section    .text
    .equ    LINUX, 5
.global _start
_start:
    nop
    pushw   $0  
    call    exit
~                                                                                                                                                                                                                                         
"love.s" 15L, 206C written
[root@cv0005759d1 stack]# as -gstabs love.s -o love.o
[root@cv0005759d1 stack]# ld -dynamic-linker /lib/ld-linux.so.2 -lc love.o -o love 
[root@cv0005759d1 stack]# gdb ./love
GNU gdb Red Hat Linux (6.5-25.el5rh)
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu"...Using host libthread_db library "/lib64/libthread_db.so.1".

(gdb) l
1       #gas command test
2       .section        .data
3       value:
4               .int    1, 2, 3, 4, 5, 6
5       valu:
6               .quad   1, 2, 3, 4, 5, 6
7       .section        .bss
8               .lcomm  buffer, 100
9       .section        .text
10              .equ    LINUX, 5
(gdb) l
11      .global _start
12      _start:
13              nop
14              pushw   $0
15              call    exit
(gdb) b 14
Breakpoint 1 at 0x400231: file love.s, line 14.
(gdb) r
Starting program: /home/stack/love 
/bin/bash: /home/stack/love: Accessing a corrupted shared library
/bin/bash: /home/stack/love: Success

Program exited with code 01.
You can't do that without a process to debug.
(gdb) x/6gd &valu
0x6003b8 <valu>:        1       2
0x6003c8 <valu+16>:     3       4
0x6003d8 <valu+32>:     5       6
(gdb)

[独孤过儿]

我的是64位的机器，所以pushl改成了pushw

[xiaopoy]

你编译时在选项中设置了 去掉汇编符号.

[hdyd]

[Quote=引用 3 楼 fetag 的回复:]
我的是64位的机器，所以pushl改成了pushw
[/Quote]

汇编程序已经支持64位了啊？

[rainsome]

[Quote=引用 4 楼 hdyd 的回复:]
引用 3 楼 fetag 的回复:
我的是64位的机器，所以pushl改成了pushw


汇编程序已经支持64位了啊？
[/Quote]
不支持，那么64位系统如何生成的。