IA32中有一个指令movl,我的问题是:“movl"中的"l"是何意？（不耻上问）

nail63547188 2004-07-14 01:52:19

mov 指令的作用是在寄存器，内存，I/O端口间移动数据，“movl"中的"l"是何意呢？“l"是什么单词的首字母呢？恭候您的答复，谢谢

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nail63547188 2004-07-14

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to 中指兄：
不好意思，刚才有冒犯的地方，还请多多原谅，谢谢你对我的帮助

lbaby 2004-07-14

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AT&T汇编是UNIX下惯用的汇编格式
l ,w,b是AT&T汇编中用来表示操作属性的限定符

l是长字（4字节)，
w是双字
b是一个字节

加在指令的后边
相当于intel中的
dword ptr
word ptr
byte ptr

比如：
subl $8, %esp
leal -792(%ebp), %eax
pushl %eax
movl -796(%ebp), %eax
sall $8, %eax
addl 12(%ebp), %eax
pushl %eax
call _strcpy
addl $16, %esp

在intel 汇编中就相当于:
sub esp,8
lea eax,dword ptr [ebp-792]
push eax
mov eax,dword ptr [ebp- 796]
...
AT&T格式的汇编和intel编的差别可以参看有关AT&T汇编的书

lbaby 2004-07-14

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我晕
就是AT&T格式的汇编，跟intel格式不一样
比如：
.file "t1.c"
.globl _label_str
.text
LC0:
.ascii "id\0"
LC1:
.ascii "u_sub\0"
LC2:
.ascii "dlvrd\0"
LC3:
.ascii "submit_date\0"
LC4:
.ascii "done_date\0"
LC5:
.ascii "stat\0"
LC6:
.ascii "err\0"
LC7:
.ascii "txt\0"
.data
.align 32
_label_str:
.long LC0
.long LC1
.long LC2
.long LC3
.long LC4
.long LC5
.long LC6
.long LC7
.globl _fmt
.text
LC8:
.ascii "%255[^:]:%255[^ ^:]\0"
.data
.align 4
_fmt:
.long LC8
.text
LC9:
.ascii "%[^ ]\0"
.align 2
.globl _no_sp
.def _no_sp; .scl 2; .type 32; .endef
_no_sp:
pushl %ebp
movl %esp, %ebp
subl $8, %esp
movl 12(%ebp), %eax
movl %eax, -4(%ebp)
L7:
movl -4(%ebp), %eax
cmpb $32, (%eax)
je L9
jmp L8
L9:
leal -4(%ebp), %eax
incl (%eax)
jmp L7
L8:
subl $4, %esp
pushl 8(%ebp)
pushl $LC9
pushl -4(%ebp)
call _sscanf
addl $16, %esp
movl 8(%ebp), %eax
leave
ret
.align 2
.globl _get_content
.def _get_content; .scl 2; .type 32; .endef
_get_content:
pushl %ebp
movl %esp, %ebp
pushl %ebx
subl $804, %esp
movl $0, -796(%ebp)
movl 8(%ebp), %eax
movl %eax, -12(%ebp)
L11:
movl -12(%ebp), %eax
cmpb $0, (%eax)
jne L14
jmp L10
L14:
leal -792(%ebp), %eax
pushl %eax
leal -280(%ebp), %eax
pushl %eax
pushl _fmt
pushl -12(%ebp)
call _sscanf
addl $16, %esp
subl $8, %esp
leal -280(%ebp), %eax
pushl %eax
leal -536(%ebp), %eax
pushl %eax
call _no_sp
addl $16, %esp
movl $0, -804(%ebp)
L15:
cmpl $7, -804(%ebp)
jle L18
jmp L16
L18:
subl $8, %esp
movl -804(%ebp), %eax
pushl _label_str(,%eax,4)
leal -536(%ebp), %eax
pushl %eax
call _strcmp
addl $16, %esp
testl %eax, %eax
jne L17
movl -804(%ebp), %eax
movl %eax, -796(%ebp)
jmp L16
L17:
leal -804(%ebp), %eax
incl (%eax)
jmp L15
L16:
cmpl $8, -804(%ebp)
jne L20
jmp L13
L20:
subl $8, %esp
leal -792(%ebp), %eax
pushl %eax
movl -796(%ebp), %eax
sall $8, %eax
addl 12(%ebp), %eax
pushl %eax
call _strcpy
addl $16, %esp
L13:
subl $12, %esp
leal -280(%ebp), %eax
pushl %eax
call _strlen
addl $16, %esp
movl %eax, %ebx
subl $12, %esp
leal -792(%ebp), %eax
pushl %eax
call _strlen
addl $16, %esp
leal (%eax,%ebx), %eax
addl -12(%ebp), %eax
incl %eax
movl %eax, -12(%ebp)
jmp L11
L10:
movl -4(%ebp), %ebx
leave
ret
.def ___main; .scl 2; .type 32; .endef
.align 32
LC10:
.ascii "id:1 u_sub:2 dlvrd:3 submit_date:4 done_date:5 stat:6 err:7 txt:8 ok:88\0"
.align 32
LC11:
.ascii " done_date:0407081236 stat:DELIVRD err:000 txt:062\320\351\310\331\243\254\266\324\261\310\260\256\307\351\265\304 id:7% u_sub:001 dlvrd:001 submit_date:0407081236\0"
LC12:
.ascii "%20s %20s\12\0"
.align 32
LC13:
.ascii "-----------------------------------------------------------\0"
.align 2
.globl _main
.def _main; .scl 2; .type 32; .endef
_main:
pushl %ebp
movl %esp, %ebp
movl $4152, %eax
call __alloca
andl $-16, %esp
movl $0, %eax
movl %eax, -4144(%ebp)
movl -4144(%ebp), %eax
call __alloca
call ___main
movl $LC10, -12(%ebp)
movl $LC11, -2076(%ebp)
subl $8, %esp
leal -2072(%ebp), %eax
pushl %eax
pushl -12(%ebp)
call _get_content
addl $16, %esp
subl $8, %esp
leal -4136(%ebp), %eax
pushl %eax
pushl -2076(%ebp)
call _get_content
addl $16, %esp
movl $0, -4140(%ebp)
L22:
cmpl $7, -4140(%ebp)
jle L25
jmp L23
L25:
subl $4, %esp
leal -2072(%ebp), %edx
movl -4140(%ebp), %eax
sall $8, %eax
leal (%eax,%edx), %eax
pushl %eax
movl -4140(%ebp), %eax
pushl _label_str(,%eax,4)
pushl $LC12
call _printf
addl $16, %esp
leal -4140(%ebp), %eax
incl (%eax)
jmp L22
L23:
subl $12, %esp
pushl $LC13
call _puts
addl $16, %esp
movl $0, -4140(%ebp)
L26:
cmpl $7, -4140(%ebp)
jle L29
jmp L27
L29:
subl $4, %esp
leal -4136(%ebp), %edx
movl -4140(%ebp), %eax
sall $8, %eax
leal (%eax,%edx), %eax
pushl %eax
movl -4140(%ebp), %eax
pushl _label_str(,%eax,4)
pushl $LC12
call _printf
addl $16, %esp
leal -4140(%ebp), %eax
incl (%eax)
jmp L26
L27:
movl $0, %eax
leave
ret
.def _puts; .scl 2; .type 32; .endef
.def _printf; .scl 2; .type 32; .endef
.def _strcpy; .scl 2; .type 32; .endef
.def _strcmp; .scl 2; .type 32; .endef
.def _strlen; .scl 2; .type 32; .endef
.def _sscanf; .scl 2; .type 32; .endef

riitso 2004-07-14