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.

 

 

C-1

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Intel 80C188XL, 80C186XL user manual Table C-1. Instruction Format Variables, Variable Description