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INSTRUCTION SET DESCRIPTIONS
C-32
OR Logical OR:
OR
dest,src
Performs the logical "inclusive or" of
the two operands (bytes or words) and
returns the result to the destination
operand. A bit in the result is set if
either or both corresponding bits in the
original operands are set; otherwise
the result bit is cleared.
Instruction Operands:
OR reg, reg
OR reg, mem
OR mem, reg
OR accum, immed
OR reg, immed
OR mem, immed
(dest) ← (dest) or (src)
(CF) ← 0
(OF) ← 0
AF ?
CF
DF –
IF –
OF
PF
SF
TF –
ZF
OUT Output:
OUT
port, accumulator
Transfers a byte or a word from the AL
register or the AX register, respec-
tively, to an output port. The port
number may be specified either with
an immediate byte constant, allowing
access to ports numbered 0 through
255, or with a number previously
placed in register DX, allowing variable
access (by changing the value in DX)
to ports numbered from 0 through
65,535.
Instruction Operands:
OUT immed8, AL
OUT DX, AX
(dest) ← (src) AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
Table C-4. Instruction Set (Continued)
Name Description Operation
Flags
Affected
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
the flag is updated after the instruction is executed