AAA - Ascii Adjust for Addition

Usage: AAA

Modifies Flags: AF CF (OF,PF,SF,ZF undefined)

Changes contents of AL to valid unpacked decimal. The high order nibble is zeroed.

AAD - Ascii Adjust for Division

Usage: AAD

Modifies Flags: SF ZF PF (AF,CF,OF undefined)

Used before dividing unpacked decimal numbers. Multiplies AH by 10 and the adds result into AL. Sets AH to zero. This instruction is also known to have an undocumented behavior.

AL := 10*AH+AL
AH := 0

AAM - Ascii Adjust for Multiplication

Usage: AAM

Modifies Flags: PF SF ZF (AF,CF,OF undefined)

Used after multiplication of two unpacked decimal numbers, this instruction adjusts an unpacked decimal number. The high order nibble of each byte must be zeroed before using this instruction. This instruction is also known to have an undocumented behavior.

AAS - Ascii Adjust for Subtraction

Usage: AAS

Modifies Flags: AF CF (OF,PF,SF,ZF undefined)

Corrects result of a previous unpacked decimal subtraction in AL. High order nibble is zeroed.

ADC - Add With Carry

Usage: ADC dest,src

Modifies Flags: AF CF OF SF PF ZF

Sums two binary operands placing the result in the destination. If CF is set, a 1 is added to the destination.

ADD - Arithmetic Addition

Usage: ADD dest,src

Modifies Flags: AF CF OF PF SF ZF

Adds "src" to "dest" and replacing the original contents of "dest". Both operands are binary.

AND - Logical And

Usage: AND dest,src

Modifies Flags: CF OF PF SF ZF (AF undefined)

Performs a logical AND of the two operands replacing the destination with the result.

ARPL - Adjusted Requested Privilege Level of Selector (286+ PM)

Usage: ARPL dest,src

Modifies Flags: ZF

Compares the RPL bits of "dest" against "src". If the RPL bits of "dest" are less than "src", the destination RPL bits are set equal to the source RPL bits and the Zero Flag is set. Otherwise the Zero Flag is cleared.

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