XLAT/XLATB -- Table Look-up Translation

XLAT/XLATB -- Table Look-up Translation D7 XLAT m8 5 Set AL to memory byte DS:[(E)BX + unsigned AL] D7 XLATB 5 Set AL to memory byte DS:[(E)BX + unsigned AL] Operation IF AddressSize = 16 THEN AL = (BX + ZeroExtend(AL)) ELSE (* AddressSize = 32 *) AL = (EBX + ZeroExtend(AL)); FI; Description XLAT changes the AL register from the table index to the table entry. AL should be the unsigned index into a table addressed by DS:BX (for an address-size attribute of 16 bits) or DS:EBX (for an address-size attribute of 32 bits). The operand to XLAT allows for the possibility of a segment override. XLAT uses the contents of BX even if they differ from the offset of the operand. The offset of the operand should have been moved intoBX/EBX with a previous instruction. The no-operand form, XLATB, can be used if the BX/EBX table will always reside in the DS segment. Flags Affected None Protected Mode Exceptions #GP(0) for an illegal memory operand effective address in the CS, DS, ES, FS, or GS segments; #SS(0) for an illegal address in the SS segment; #PF(fault-code) for a page fault Real Address Mode Exceptions Interrupt 13 if any part of the operand would lie outside of the effective address space from 0 to 0FFFFH Virtual 8086 Mode Exceptions Same exceptions as in Real Address Mode; #PF(fault-code) for a page fault