Intel 80C186XL Instruction Set Descriptions, Table C-4.Instruction Set Continued, C-38, Name

Models: 80C186XL 80C188XL

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INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name

Description

Operation

Flags

Affected

 

 

 

 

 

 

 

RET

Return:

(IP) ((SP) = 1:(SP))

AF –

 

RET optional-pop-value

(SP) (SP) + 2

CF –

 

if

DF –

 

Transfers control from a procedure

 

inter-segment

IF –

 

back to the instruction following the

 

then

OF –

 

CALL that activated the procedure.

 

(CS) ((SP) + 1:(SP))

PF –

 

The assembler generates an intra-

 

(SP) (SP) + 2

SF –

 

segment RET if the programmer has

 

if

TF –

 

defined the procedure near, or an

 

add immed8 to SP

ZF –

 

intersegment RET if the procedure has

 

then

 

 

been defined as far. RET pops the

 

 

(SP) (SP) + data

 

 

word at the top of the stack (pointed to

 

 

 

 

 

by register SP) into the instruction

 

 

 

pointer and increments SP by two. If

 

 

 

RET is intersegment, the word at the

 

 

 

new top of stack is popped into the CS

 

 

 

register, and SP is again incremented

 

 

 

by two. If an optional pop value has

 

 

 

been specified, RET adds that value to

 

 

 

SP.

 

 

 

Instruction Operands:

 

 

 

RET immed8

 

 

 

 

 

 

ROL

Rotate Left:

(temp) count

AF –

 

ROL dest, count

do while (temp) 0

CF

 

(CF) high-order bit of (dest)

DF –

 

Rotates the destination byte or word

 

(dest) (dest) × 2 + (CF)

IF –

 

left by the number of bits specified in

 

(temp) (temp) – 1

OF ¸

 

the count operand.

if

PF –

 

Instruction Operands:

 

count = 1

SF –

 

ROL reg, n

then

TF –

 

ROL mem, n

if

ZF –

 

ROL reg, CL

high-order bit of (dest) (CF)

 

 

ROL mem CL

then

 

 

 

(OF) 1

 

 

 

else

 

 

 

(OF) 0

 

 

 

else

 

 

 

(OF) undefined

 

 

 

 

 

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

the flag is updated after the instruction is executed

C-38

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Intel 80C186XL Instruction Set Descriptions, Table C-4.Instruction Set Continued, C-38, Name, Operation, Flags, Affected