7. CONTROL SYSTEM ARITHMETIC LOGIC UNIT FLAGS Instruction Queue OPERANDS ∑ Memory Interface EU BIU Instruction Decoder DESTINATION INDEX (DI) SOURCE INDEX (SI) BASE POINTER (BP) STACK POINTER (SP) DL DH CL CH BL BH AL AH EXTRA SEGMENT (ES) INSTRUCTION POINTER (IP) DATA SEGMENT (DS) STACK SEGMENT (SS) CODE SEGMENT (CS) 6 5 4 3 2 1
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12. Flag Register CF U PF U AF U ZF SF TF IF DF OF U U U U DIRECTION FLAG DF 9. INTERRUPT FLAG IF 8. Control Flags TRAP FLAG TF 7. OVERFLOW FLAG OF 6. SIGN FLAG SF 5. ZERO FLAG ZF 4. AUXILIARY CARRY AF 3. PARITY FLAG PF 2. Conditional Flags (Compatible with 8085, except OF) CARRY FLAG CF 1.
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14. CONTROL SYSTEM ARITHMETIC LOGIC UNIT FLAGS Instruction Queue OPERANDS ∑ Memory Interface EU BIU Instruction Decoder DESTINATION INDEX (DI) SOURCE INDEX (SI) BASE POINTER (BP) STACK POINTER (SP) DL DH CL CH BL BH AL AH EXTRA SEGMENT (ES) INSTRUCTION POINTER (IP) DATA SEGMENT (DS) STACK SEGMENT (SS) CODE SEGMENT (CS) 6 5 4 3 2 1
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18. Memory 00000H FFFFFH 1MB Address Range 64KB Memory Segment Only 4 such segments can be addressed at a time 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 7 6 5 4