Appendix c instruction set descriptions, Table c1. instruction format variables – Intel 80C188XL User Manual

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C-1

APPENDIX C

INSTRUCTION SET DESCRIPTIONS

This appendix provides reference information for the 80C186 Modular Core family instruction
set. Tables C-1 through C-3 define the variables used in Table C-4, which lists the instructions
with their descriptions and operations.

Table C-1. Instruction Format Variables

Variable

Description

dest

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.

src

A register, memory location or immediate value that is used in the operation, but is not
altered by the instruction

target

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 transferred
indirectly.

disp8

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.

accum

Register AX for word transfers, AL for bytes.

port

An I/O port number; specified as an immediate value of 0–255, or register DX (which
contains port number in range 0–64K).

src-string

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.

dest-string

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 operation.

count

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).

interrupt-type

Immediate value of 0–255 identifying interrupt pointer number.

optional-pop-value

Number of bytes (0–64K, ordinarily an even number) to discard from the stack.

external-opcode

Immediate value (0–63) that is encoded in the instruction for use by an external
processor.

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