PIC18F010T-I/SN View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC18F010T-I/SN

High Performance Microcontrollers

Microchip Technology 

PIC18F010/020

SUBWF

Syntax:

Subtract WREG from f

[ label ] SUBWF f [ ,d [,a] ]

Operands:

0 ≤ f ≤ 255

d ∈ [0,1]

a ∈ [0,1]

Operation:

(f) – (WREG) → dest

Status Affected: N,OV, C, DC, Z

Encoding:

0101 11da ffff ffff

Description:

Subtract WREG from register 'f'

(2’s complement method). If 'd' is

0, the result is stored in WREG. If

'd' is 1, the result is stored back in

register 'f' (default). If ’a’ is 0, the

Access Bank will be selected,

overriding the BSR value. If ’a’ is

1, the Bank will be selected as per

the BSR value.

Words:

1

Cycles:

1

Q Cycle Activity:

Q1

Decode

Q2

Read

register ’f’

Q3

Process

Data

Q4

Write to

destination

SUBWF

Example 1:

Subtract WREG from f (cont’d)

SUBWF REG

Before Instruction

REG = 3

WREG = 2

C

=?

After Instruction

REG = 1

WREG = 2

C

=1

Z

=0

N

=0

; result is positive

Example 2:

SUBWF REG, W

Before Instruction

REG = 2

WREG = 2

C

=?

After Instruction

REG = 2

WREG = 0

C

=1

Z

=1

N

=0

; result is zero

Example 3:

SUBWF REG

Before Instruction

REG = 1

WREG = 2

C

=?

After Instruction

REG =

WREG =

C

=

Z

=

N

=

0xFF ;(2’s complement)

2

0 ; result is negative

0

1

DS41142A-page 132

Preliminary

 2001 Microchip Technology Inc.

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