80C186EB/80C188EB Microprocessor User's Manual - CEUNES

INSTRUCTION SET DESCRIPTIONSTable C-4. Instruction Set (Continued)Name Description OperationFlagsAffectedXLATXORNOTE:Translate:XLAT translate-tableReplaces a byte in the AL register witha byte from a 256-byte, user-codedtranslation table. Register BX isassumed to point to the beginning ofthe table. The byte in AL is used as anindex into the table and is replaced bythe byte at the offset in the table correspondingto AL's binary value. The firstbyte in the table has an offset of 0. Forexample, if AL contains 5H, and thesixth element of the translation tablecontains 33H, then AL will contain 33Hfollowing the instruction. XLAT isuseful for translating characters fromone code to another, the classicexample being ASCII to EBCDIC orthe reverse.Instruction Operands:XLAT src-tableExclusive Or:XOR dest, srcPerforms the logical "exclusive or" ofthe two operands and returns theresult to the destination operand. A bitin the result is set if the correspondingbits of the original operands containopposite values (one is set, the otheris cleared); otherwise the result bit iscleared.Instruction Operands:XOR reg, regXOR reg, memXOR mem, regXOR accum, immedXOR reg, immedXOR mem, immedAL ← ((BX) + (AL)) AF –CF –DF –IF –OF –PF –SF –TF –ZF –(dest) ← (dest) xor (src)(CF) ← 0(OF) ← 0The three symbols used in the Flags Affected column are defined as follows:– the contents of the flag remain unchanged after the instruction is executed? the contents of the flag is undefined after the instruction is executedüthe flag is updated after the instruction is executedAF ?CF üDF –IF –OF üPF üSF üTF –ZF üC-47