Bit Name Function
0 CF Carry Flag -- Set on high-order bit carry or borrow; cleared
otherwise.
2 PF Parity Flag -- Set if low-order eight bits of result contain
an even number of 1 bits; cleared otherwise.
4 AF Adjust flag -- Set on carry from or borrow to the low order
four bits of AL; cleared otherwise. Used for decimal
arithmetic.
6 ZF Zero Flag -- Set if result is zero; cleared otherwise.
7 SF Sign Flag -- Set equal to high-order bit of result (0 is
positive, 1 if negative).
11 OF Overflow Flag -- Set if result is too large a positive number
or too small a negative number (excluding sign-bit) to fit in
destination operand; cleared otherwise.
T = instruction tests flag
M = instruction modifies flag
(either sets or resets depending on operands)
0 = instruction resets flag
-- = instruction's effect on flag is undefined
blank = instruction does not affect flag
Instruction OF SF ZF AF PF CF AAA -- -- -- TM -- M AAS -- -- -- TM -- M AAD -- M M -- M -- AAM -- M M -- M -- DAA -- M M TM M TM DAS -- M M TM M TM ADC M M M M M TM ADD M M M M M M SBB M M M M M TM SUB M M M M M M CMP M M M M M M CMPS M M M M M M SCAS M M M M M M NEG M M M M M M DEC M M M M M INC M M M M M IMUL M -- -- -- -- M MUL M -- -- -- -- M RCL/RCR 1 M TM RCL/RCR count -- TM ROL/ROR 1 M M ROL/ROR count -- M SAL/SAR/SHL/SHR 1 M M M -- M M SAL/SAR/SHL/SHR count -- M M -- M M SHLD/SHRD -- M M -- M M BSF/BSR -- -- M -- -- -- BT/BTS/BTR/BTC -- -- -- -- -- M AND 0 M M -- M 0 OR 0 M M -- M 0 TEST 0 M M -- M 0 XOR 0 M M -- M 0
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Appendices
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Appendix B -- Complete Flag Cross-Reference
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Appendix D -- Condition Codes