汇编语言标记寄存器标记位

在8086CPU中，有一种标记寄存器，长度为16bit；

其中存储的信息被称为程序状态字(Program Status Word,PSW),以下将该寄存器简称为flag。

功能：1）用来存储相关指令的某些执行结果；

2）用来为CPU执行相关指令提供行为依据；

3）用来控制CPU的相关工作方式。

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" alt="" />

flag寄存器各位示意图

注明：16位中未标明字符的各位在8086CPU中没有使用，无意义；

标明字符的各位具有特殊含义。

位符号英文全称中文名称说明（数学或逻辑运算）

0 CF Carry Flag 进位标记位无符号数运算结果是否进位/借位

2 PF Parity Flag 奇偶标志位运算结果二进制表示各位为1的个数（奇偶表示）

4 AF Auxiliary carry Flag 辅助进位标记位 AF=1时,向高位或高字节进位或借位

6 ZF Zero Flag 零标志位运算结果是否为0

7 SF Sign Flag 符号标记位有符号数运算结果的正负

8 TF Trace Flag 跟踪标记位 TF=1,产生单步中断，引发中断过程

9 IF Interrupt-enable Flag 中断允许标记位 IF=1/0,CPU允许中断或关闭中断

10 DF Direction Flag 方向标记位字符串处理指令中DF=0/1，控制每次操作si，di的增减

11 OF Overflow Flag 溢出标记位有符号数运算结果是否溢出

注明：数学或逻辑运算指令才会影响flag,包括add,sub,mul,div,inc,dec,or,and等；

mov,push,pop等传送指令对flag没有影响；

TF跟踪标志（为调试机器或调试程序发现故障而设置）:

TF=1，CPU在执行完一条指令后将引发单步中断，转去执行中断处理程序；

TF=0，CPU处在连续工作状态。

IF中断允许标记位（可屏蔽中断的中断过程中CPU检测IF确定是否屏蔽中断）：

IF=1，CPU执行完当前指令后，响应中断，引发中断过程；

IF=0，CPU执行完当前指令后，不响应中断。

sti,则IF=1；

cti,则IF=0.

各寄存器的详细说明参考：http://www.cnblogs.com/ant-colonies/p/6008322.html

标记寄存器在Debug中的表示
AX=0000 BX=0000 CX=0000 DX=0000 SP=FFEE BP=0000 SI=0000 DI=0000
DS=**** ES=**** SS=**** CS=**** IP=0100 NV UP EI PL NZ NA PO NC
位    标志     值为的标志                  值为的标志
0     CF      CY(CarrY)                     NC(Not Carry)
2     PF       PE(Parity Even)             PO(Parity Odd)
4     AF      AC(Auxiliary Carry)        NA(No Auxiliary carry)
6   ZF      ZR(ZeRo)                     NZ(Not Zero)
7    SF      NG(NeGative)                PL(Positive)
9    IF       DI(Disabled Interrupt)    EI(Inabled Interrupt)
10   DF      DN(DowN)                    UP(Up)
11   OF      OV(Overflow)                NV(Not Overflow)

标记位CF与OF：

adc是带进位的加法指令
指令格式：adc object1,object2
功能：object1=object1+object2+CF
举例：adc ax,bx即 (ax)=(ax)+(bx)+CF

sbb是带借位的减法指令
指令格式：sbb object1,object2
功能：object1=object1-object2-CF
举例：adc ax,bx即 (ax)=(ax)-(bx)-CF

注：adc和sbb可以用于解决add,sub运算时的进位无法存储的问题；

adc(add & CF),带进位的加法;

sbb(sub & below),带错位的减法；

标志位CF与OF的比较：

1111 1111    8bit表示范围               对应标志位      超出表示范围时
2^8-1(255)     无符号数[0,255]         CF                 向更高位发生进位或借位
2^7-1(127)     有符号数[-128~127]   OF                 发生溢出

cmp指令
指令格式：cmp object1,object2
功能：计算操作对象object1-object2,但不保存结果，仅根据计算结果对标志寄存器进行设置
举例：
cmp ax,ax ;（无符号数之间的比较）
执行后ax值不变，zf=1,pf=1,cf=0,of=0 ;
mov ax,8
mov bx,3
cmp ax,bx
执行后：(ax)=8,zf=0,pf=1,cf=0,of=0。

指令 cmp ax,bx (无符号数之间比较,参考的标记位zf,cf)
zf=1,则(ax)=(bx)
zf=0,则(ax)!=(bx)
cf=1,则(ax)<(bx)
cf=0,则(ax)>=(bx)
cf=0且zf=0,则(ax)>(bx)
cf=1或zf=1,则(ax)<=(bx)

指令 cmp ah,bh (有符号数之间比较,参考的标记位sf,of,zf)
sf=1,且of=0,则(ah)<(bh)
sf=1,且of=1,则(ah)>(bh)
sf=0,且of=1,则(ah)<(bh)
sf=0,且of=0,则(ah)>=(bh)

条件转移指令：
"转移"的本质是——修改IP;"条件"指的是可以根据某种条件，决定是否修改IP
所有条件转移指令的转移位移范围为[-128,127]
1)jcxz,即当(cx)=0时，即修改IP(实现转移)
2)被cmp指令影响标记寄存器标记位，与以下条件转移指令配合使用
常用的根据无符号数的比较结果进行转移的条件转移指令：
指令              含义                 检测相关的标志位
je                 等于则转移          zf=1
jne               不等于则转移       zf=0
jb               小于则转移         cf=1
jnb               不小于则转移      cf=0
ja                 大于则转移         cf=0且zf=0
jna               不大于则转移       cf=1或zf=1

注：j-jmp
      e-equal   ne-not equal
      b-below nb-not below
      a-above na-not above

标记位DF与串传送指令：

df(direction flag),方向标志位，控制每次操作后si,di的增减
df=0,si,di递增
df=1,si,di递减
字符串传送指令：
格式：movsb                   ;mov string byte
功能：1)((es)*16+(di))=((ds)*16+(si))
             即：mov es:[di],byte ptr ds:[si]
      2)当df=0, (si)=(si)+1
                    (di)=(di)+1
           即：inc si
                  inc di
       当df=1, (si)=(si)-1
               (di)=(di)-1
           即：dec si
                   dec di

格式：movsw                   ;mov string word
功能：1)((es)*16+(di))=((ds)*16+(si))
             即：mov es:[di],word ptr ds:[si]
      2)当df=0, (si)=(si)+2
                    (di)=(di)+2
           即：add si,2
                  add di,2
       当df=1, (si)=(si)-2
               (di)=(di)-2
           即：sub si
                   sub di
一般movsb/movsw与rep配合使用   ;rep-repeat
格式：rep movsb
    即：s:movsb
          loop s       ;所以rep的作用是根据cx的值，进行重复串传送

设置df的指令：
cld      ;将df置0,字符串传送——偏移地址递增的方向      clear df
std   ;将df置1,字符串传送——偏移地址递减的方向      set df

assume cs:code,ds:data

data segment

  db 'Welcome to masm!'            ;将此字符串复制到相同段地址，偏移地址为16的内存位置

  db 16 dup (0)

data ends

code segment

  start: mov ax,data

         mov ds,ax

         mov es,ax

	 mov si,0

	 mov di,16

	 mov cx,8

	 cld

	 rep movsw

	 mov ax,4c00h

	 int 21h

code ends

end start

pushf和popf:

pushf的功能——将标记寄存器的值压栈；

popf的功能——出栈，将值送入标记寄存器中。

注：此文参考网络和《汇编语言》(王爽，第二版)

巴特西

汇编语言标记寄存器标记位_NV UP EI NG NZ AC PE CY

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