Intel 80C186EA, User Manual

Page: 336 / 417

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.