INSTRUCTION SET DESCRIPTIONS

 

Table C-4. Instruction Set (Continued)

 

 

 

 

 

 

Name

Description

 

Operation

Flags

 

Affected

 

 

 

 

 

 

 

 

 

CLI

Clear Interrupt-enable Flag:

(IF) 0

 

AF –

 

CLI

 

 

CF –

 

 

 

DF –

 

Zeroes the interrupt-enable flag (IF).

 

 

 

 

 

IF ¸

 

When the interrupt-enable flag is

 

 

OF –

 

cleared, the 8086 and 8088 do not

 

 

 

 

 

PF –

 

recognize an external interrupt request

 

 

 

 

 

SF –

 

that appears on the INTR line; in other

 

 

 

 

 

TF –

 

words maskable interrupts are

 

 

 

 

 

ZF –

 

disabled. A non-maskable interrupt

 

 

 

 

 

 

 

appearing on NMI line, however, is

 

 

 

 

honored, as is a software interrupt.

 

 

 

 

Instruction Operands:

 

 

 

 

none

 

 

 

 

 

 

 

 

CMC

Complement Carry Flag:

if

 

AF –

 

CMC

(CF) = 0

 

CF ¸

 

Toggles complement carry flag (CF) to

then

 

DF –

 

(CF) 1

 

IF –

 

its opposite state and affects no other

 

 

else

 

OF –

 

flags.

 

 

(CF) 0

 

PF –

 

Instruction Operands:

 

 

 

 

SF –

 

none

 

 

TF –

 

 

 

 

ZF –

 

 

 

 

 

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-9

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Intel 80C188XL, 80C186XL user manual Clear Interrupt-enable Flag, Complement Carry Flag