beautypg.com

Zilog Z16F2810 User Manual

Page 185

background image

UM018809-0611

SUB Instruction

ZNEO

®

CPU Core

User Manual

169

SUB

Definition

Subtract

Syntax

SUB dst, src

Operation

dst

dst – src

Description

This instruction subtracts the source operand from the destination operand. The result is stored in
the destination address or register. The contents of the source operand are unaffected. The ZNEO
CPU performs subtraction by adding the two’s complement of the source operand to the destina-
tion operand.

Flags

Flags are set based on the memory destination size, or 32 bits for register destinations.

7

6

5

4

3

2

1

0

C

Z

S

V

B

CIRQE IRQE

*

*

*

*

*

Legend

C

= Set to 1 if the result generated a borrow; otherwise set to 0.

Z

= Set to 1 if the result is zero; otherwise, set to 0.

S

= Set to 1 if the result msb is 1; otherwise set to 0.

V

= Set to 1 if an arithmetic overflow occurs; otherwise set to 0.

B

= Set to 1 if the initial destination or source value is 0; otherwise set to 0.

CIRQE

= No change.

IRQE

= No change.

Note:

This manual is related to the following products: