学 Win32 汇编[28] - 跳转指令: JMP、JECXZ、JA、JB、JG、JL、JE、JZ、JS、JC、JO、JP 等

http://www.cnblogs.com/del/archive/2010/04/16/1713886.html

跳转指令分三类:
一、无条件跳转: JMP;
二、根据 CX、ECX 寄存器的值跳转: JCXZ(CX 为 0 则跳转)、JECXZ(ECX 为 0 则跳转);
三、根据 EFLAGS 寄存器的标志位跳转, 这个太多了.

根据标志位跳转的指令:

JE   ;等于则跳转
JNE  ;不等于则跳转

JZ   ;为 0 则跳转
JNZ  ;不为 0 则跳转

JS   ;为负则跳转
JNS  ;不为负则跳转

JC   ;进位则跳转
JNC  ;不进位则跳转

JO   ;溢出则跳转
JNO  ;不溢出则跳转

JA   ;无符号大于则跳转
JNA  ;无符号不大于则跳转
JAE  ;无符号大于等于则跳转
JNAE ;无符号不大于等于则跳转

JG   ;有符号大于则跳转
JNG  ;有符号不大于则跳转
JGE  ;有符号大于等于则跳转
JNGE ;有符号不大于等于则跳转

JB   ;无符号小于则跳转
JNB  ;无符号不小于则跳转
JBE  ;无符号小于等于则跳转
JNBE ;无符号不小于等于则跳转

JL   ;有符号小于则跳转
JNL  ;有符号不小于则跳转
JLE  ;有符号小于等于则跳转
JNLE ;有符号不小于等于则跳转

JP   ;奇偶位置位则跳转
JNP  ;奇偶位清除则跳转
JPE  ;奇偶位相等则跳转
JPO  ;奇偶位不等则跳转

跳转相关的标志位:

11	10	9	8	7	6	5	4	3	2	1	0
OF	DF	IF	TF	SF	ZF		AF		PF		CF
溢出				符号	零	未用	辅助	未用	奇偶	未用	进位

JMP 测试

; Test28_1.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    jmp @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

;测试结果应该是:
;1
;4
;以下都应该是这样.

JE 测试

; Test28_2.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov eax, 123
    cmp eax, 123
    je @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JZ 测试

; Test28_3.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    xor eax, eax
    jz @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JS 测试

; Test28_4.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    xor eax, eax
    dec eax
    js @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JC 测试

; Test28_5.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov al, 0FFh
    add al, 1
    jc @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JO 测试

; Test28_6.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov al, -128
    sub al, 1
    jo @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JA 测试

; Test28_7.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov eax, 22
    cmp eax, 11
    ja @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JG 测试

; Test28_8.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov eax, 1
    cmp eax, -1
    jg @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JP 测试

; Test28_9.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    mov al, 00001110b
    inc al
    jp @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main

JECXZ 测试

; Test28_10.asm;
.386
.model flat, stdcall

include    windows.inc
include    kernel32.inc
include    masm32.inc
include    debug.inc
includelib kernel32.lib
includelib masm32.lib
includelib debug.lib

.code
main proc
    PrintText '1'
    xor ecx, ecx
    jecxz @F
    PrintText '2'
    PrintText '3'
@@: PrintText '4'
    ret
main endp
end main