Intel iAPX 86/88 User Manual page 38

8086/8088 CPU
Table 1·12 Key to Instruction Coding Formats
IDENTIFIER
destination
source
source-table
target
short-label
accumulator
port
source-string
dest-string
count
interrupt-type
USEDIN
data transfer,
bit manipulation
data transfer,
arithmetic,
bit manipulation
XLAT
JMP, CALL
cond. transfer,
iteration control
IN,OUT
IN,OUT
string ops.
string ops.
shifts, rotates
INT
optional-pop-value RET
external-opcode ESC
EXPLANATION
A register or memory location that may contain data
operated on by the instruction, and which receives (is
replaced by) the result of the operation.
A register, memory location or immediate value that is
used in the operation, but is not altered by the instruc-
tion.
Name of memory translation table addressed by register
BX.
A label to which control is to be transferred directly, or a
register or memory location whose
content
is the
address of the location to which control is to be transfer-
red indirectly.
A label to which control is to be conditionally
transferred; must lie within -128 to +127 bytes of the first
byte of the next instruction.
Register AX for word transfers, AL for bytes.
An I/O port number; specified as an immediate value of
0-255, or register DX (which contains port number in
range 0-64k).
Name of a string in memory that is addressed by register
SI; used only to identify string as byte or word and
specify segment override, if any. This string is used in
the operation, but is not altered.
Name of string in memory that is addressed by register
DI; used only to identify string as byte or word. This
string receives (is replaced by) the result of the opera-
tion.
Specifies number of bits to shift or rotate; written as
immediate value 1 or register CL (which contains the
count in the range 0-255).
Immediate value of 0-255 identifying interrupt pOinter
number.
Number of bytes (0-64k, ordinarily an even number) to
discard from stack.
Immediate value (0-63) that is encoded in the instruction
for use by an external processor.
1-22
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