Please enable JavaScript.

Coggle requires JavaScript to display documents.

Ch6 (Boolean and Comparison Instructions (XOR Instruction (Flag變化 (CF = 0,…

- - - - CF = 0, OF = 0
      - 改變 SF、ZF、PF
    - - XOR(reg,0) Can be used to check the parity of a number without changing its value
      - xOR ah,al
        
        檢查16-bits的parity (因為兩個1會被cancel掉)
        
        檢查32bits data 則要拆部分來XOR ( B0 XOR B1 XOR B2 XOR B3)
    - - 可用來做翻轉(0變1，1變0)
  - - - 執行一個隱含的減法
      - 兩個運算元都不會被修改
    - - Destination < source ZF = 0, CF = 1 (借位)
      - Destination > source ZF = 0, CF = 0 (沒借位)
      - Destination = source ZF = 1, CF = 0
    - - Destination < source SF != OF
      - Destination > source SF = OF
      - Destination = source ZF = 1
- - - - 特定旗標值
        
        JZ/JNZ : ZF = 1 / 0
        
        JC/JNC : CF = 1 / 0
        
        JO/JNO : OF = 1 / 0
        
        JS/JNS : SF = 1 / 0
        
        JP/JNP : PF = 1 / 0
      - 相等
        
        JE/JNE : leftOP = rigntOP / leftOP != rigntOP
        
        JCXZ/JECXZ/JRCXZ : CX/ECX/RCX = 0
      - 無號數比較
        
        JA/JNBE/JAE/JNB/JB/JNAE/JBE/JNA
        
        A : above (>)
        
        E : eaual (=)
        
        B : below (<)
      - 有號數比較
        
        JG = JNLE (>)
        
        JGE = JNL (>=)
        
        JL = JNGE (<)
        
        JLE = JNG (<=)
      - 有號無號的比較
        
        無號 : A、B、E
        
        有號 : G、L、E