S3C84E5/C84E9/P84E9

INSTRUCTION SET

 

 

COM — Complement

COMdst

Operation: dst NOT dst

The contents of the destination location are complemented (one's complement). All "1s" are changed to "0s", and vice-versa.

Flags:

C:

Unaffected.

 

Z: Set if the result is "0"; cleared otherwise.

 

S: Set if the result bit 7 is set; cleared otherwise.

 

V: Always reset to "0".

 

D:

Unaffected.

 

H:

Unaffected.

Format:

 

Bytes Cycles Opcode

Addr Mode

(Hex)

dst

opc

dst

2

4

60

R

 

4

61

IR

Examples: Given: R1 = 07H and register 07H = 0F1H:

COM

R1

R1

=

0F8H

COM

@R1

R1

=

07H, register 07H = 0EH

In the first example, the destination working register R1 contains the value 07H (00000111B). The statement "COM R1" complements all the bits in R1: all logic ones are changed to logic zeros, and logic zeros to logic ones, leaving the value 0F8H (11111000B).

In the second example, Indirect Register (IR) addressing mode is used to complement the value of the destination register 07H (11110001B), leaving the new value 0EH (00001110B).

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Samsung S3C84E5 COM Complement, COMdst Operation dst ← not dst, Opc Dst Examples Given R1 = 07H and register 07H = 0F1H