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Name
XLAT
Translate:
XLAT translate-table
Replaces a byte in the AL register with
a byte from a 256-byte, user-coded
translation table. Register BX is
assumed to point to the beginning of
the table. The byte in AL is used as an
index into the table and is replaced by
the byte at the offset in the table corre-
sponding to AL's binary value. The first
byte in the table has an offset of 0. For
example, if AL contains 5H, and the
sixth element of the translation table
contains 33H, then AL will contain 33H
following the instruction. XLAT is
useful for translating characters from
one code to another, the classic
example being ASCII to EBCDIC or
the reverse.
Instruction Operands:
XLAT src-table
XOR
Exclusive Or:
XOR dest, src
Performs the logical "exclusive or" of
the two operands and returns the
result to the destination operand. A bit
in the result is set if the corresponding
bits of the original operands contain
opposite values (one is set, the other
is cleared); otherwise the result bit is
cleared.
Instruction Operands:
XOR reg, reg
XOR reg, mem
XOR mem, reg
XOR accum, immed
XOR reg, immed
XOR mem, immed
NOTE: The 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 executed
ü
the flag is updated after the instruction is executed
Table C-4. Instruction Set (Continued)
Description
INSTRUCTION SET DESCRIPTIONS
Operation
AL ← ((BX) + (AL))
(dest) ← (dest) xor (src)
(CF) ← 0
(OF) ← 0
Flags
Affected
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
AF ?
ü
CF
DF –
IF –
ü
OF
ü
PF
ü
SF
TF –
ü
ZF
C-47
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