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Registers 76543210 processor control clc e clear

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Unformatted text preview: ----|) HLT e Halt 11110100 (|ODITSZAPC| = |---------|) WAIT e Wait 10011011 (|ODITSZAPC| = |---------|) ESC e Escape (to External Device) 11011xxx LOCK e Bus Lock Prefix 11110000 NOTES AL e 8-bit accumulator AX e 16-bit accumulator CX e Count register DS e Data segment ES e Extra segment Above below refers to unsigned value Greater e more positive Less e less positive (more negative) signed values if d e 1 then ‘‘to’’ reg if d e 0 then ‘‘from’’ reg if w e 1 then word instruction if w e 0 then byte instruction if mod e 11 then r m is treated as a REG field if mod e 00 then DISP e 0 disp-low and disp-high are absent if mod e 01 then DISP e disp-low sign-extended to 16 bits disp-high is absent if mod e 10 then DISP e disp-high disp-low if r m e 000 then EA e (BX) a (SI) a DISP if r m e 001 then EA e (BX) a (DI) a DISP if r m e 010 then EA e (BP) a (SI) a DISP if r m e 011 then EA e (BP) a (DI) a DISP if r m e 100 then EA e (SI) a DISP if r m e 101 then EA e (DI) a DISP if r m e 110 then EA e (BP) a DISP if r m e 111 then EA e (BX) a DISP DISP follows 2nd byte of instruction (before data if required) except if mod e 00 and r m e 110 then EA e disp-high disp-low The codes used for 'Affected Flags' column are: |-*01? mod x x x r m (|ODITSZAPC| = |---------|) (|ODITSZAPC| = |---------|) if s w e 01 then 16 bits of immediate data form the operand if s w e 11 then an immediate data byte is sign extended to form the 16-bit operand if v e 0 then ‘‘count’’ e 1 if v e 1 then ‘‘count’’ in (CL) x e don’t care z is used for string primitives for comparison with ZF FLAG Rotate Instructions CF RCL SEGMENT OVERRIDE PREFIX 0 0 1 reg 1 1 0 CF REG is assigned according to the following table 16-Bit (w e 1) 000 001 010 011 100 101 110 111 AX CX DX BX SP BP SI DI 8-Bit (w e 0) 000 001 010 011 100 101 110 111 AL CL DL BL AH CH DH BH ROL Segment CF 00 ES 01 CS 10 SS 11 DS Instructions which reference the flag register file as a 16-bit object use the symbol FLAGS to represent the file FLAGS e X X X X (OF) (DF) (IF) (TF) (SF) (ZF) X (AF) X (PF) X (CF) 0 SHL CF 0 SAL CF RCR Intentionally Blank CF ROR | Unaffected/Affected/Reset/Set/Unknown CF 0 SHR NOTES: Tabulated and Edited by Dr. Mohammed Hawa, University of Jordan. Version 1.1, June, 2005. CF SAR ASCII Character Set Conditional Jump Instructions Instruction Description JC Jump if carry JNC Jump if no carry JZ Jump if zero JNZ Jump if not zero JS Jump if sign JNS Jump if no sign JO Jump if overflow JNO Jump if no overflow JP Jump if parity JPE Jump if parity even JNP Jump if no parity JPO Jump if parity odd Instruction JA JNBE JAE JNB JB JNAE JBE JNA JE JNE Cond...
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