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#2
锋了2014-04-21 15:16
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$ uname -a
Linux ------ 2.6.32-431.11.2.el6.x86_64 #1 SMP Tue Mar 25 19:59:55 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
一、movq指令加载内存中的数据到mmx寄存器后，在gdb中使用print命令查看mmx寄存器显示为void
汇编程序：
程序代码：.section .data
intv:
.int 1, -1
bytev:
.byte 0x10, 0x05, 0xff, 0x32, 0x47, 0xe5, 0x23, 0x12
quadv:
.quad 123456
.section .text
.globl _start
_start:
nop
movq intv, %mm0
movq bytev, %mm1
movq quadv, %mm2
movl $1, %eax
movl $0, %ebx
int $0x80
intv:
.int 1, -1
bytev:
.byte 0x10, 0x05, 0xff, 0x32, 0x47, 0xe5, 0x23, 0x12
quadv:
.quad 123456
.section .text
.globl _start
_start:
nop
movq intv, %mm0
movq bytev, %mm1
movq quadv, %mm2
movl $1, %eax
movl $0, %ebx
int $0x80
编译链接：
$ as -gstabs -o mmx.o mmx.s
$ ld -o mmx mmx.o
查看
（gdb）print $mm0
$1 = void
(gdb)print $mm1
$2 = void
(gdb)print $mm2
$3 = void
为什么显示的是void而不是加载进去的值？？？
二、使用pushl指令出错
程序代码：.section .data
value:
.int 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60
output:
.asciz "The value is %d\n"
.section .text
.globl _start
_start:
nop
movl $0, %edi
loop:
movl value(, %edi, 4), %eax
pushl %eax
pushl $output
call printf
addl $8, %esp
inc %edi
cmpl $11, %edi
jne loop
movl $0, %ebx
movl $1, %eax
int $0x80
value:
.int 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60
output:
.asciz "The value is %d\n"
.section .text
.globl _start
_start:
nop
movl $0, %edi
loop:
movl value(, %edi, 4), %eax
pushl %eax
pushl $output
call printf
addl $8, %esp
inc %edi
cmpl $11, %edi
jne loop
movl $0, %ebx
movl $1, %eax
int $0x80
编译出错：
$ as -gstabs -o loop.o loop.s
loop.s: Assembler messages:
loop.s:13: Error: suffix or operands invalid for `push'
loop.s:14: Error: suffix or operands invalid for `push'
网上查说加--32参数：
$ as -gstabs -o loop.o loop.s
试了下，编译通过了。
链接出错：
$ ld -o loop loop.o
loop.o: could not read symbols: File in wrong format
$ file loop.o
loop.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not stripped
请问造成上述2个问题的原因什么？该如何解
[ 本帖最后由 锋了 于 2014-4-14 22:17 编辑 ]