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INSTRUCTION SET DESCRIPTIONS
Name
INC
Increment:
INC dest
Adds one to the destination operand.
The operand may be byte or a word
and is treated as an unsigned binary
number (see AAA and DAA).
Instruction Operands:
INC reg
INC mem
INS
In String:
INS dest-string, port
Performs block input from an I/O port
to memory. The port address is placed
in the DX register. The memory
address is placed in the DI register.
This instruction uses the ES register
(which cannot be overridden). After the
data transfer takes place, the DI
register increments or decrements,
depending on the value of the direction
flag (DF). The DI register changes by 1
for byte transfers or 2 for word
transfers.
Instruction Operands:
INS dest-string, port
INS (repeat) dest-string, port
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
C-18
Table C-4. Instruction Set (Continued)
Description
Operation
(dest) ← (dest) + 1
(dest) ← (src)
Flags
Affected
ü
AF
CF –
DF –
IF –
ü
OF
ü
PF
ü
SF
TF –
ü
ZF
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
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