3 INSTRUCTION SET

RZF

Reset zero flag

 

Source Format:

RZF

 

 

 

 

 

 

 

 

 

 

 

 

 

Operation:

Z

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OP-Code:

1

 

1

1

1

0

1

0

1

1

1

0

1

 

F5DH

 

MSB

 

 

 

 

 

 

 

 

 

 

LSB

 

Type:

VI

 

 

 

 

 

 

 

 

 

 

 

 

 

Clock Cycles:

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Flag:

C – Not affected

 

 

Z – Reset

 

 

D – Not affected

 

 

I – Not affected

 

Description:

Resets the Z (zero) flag.

 

 

 

Example:

 

 

 

 

 

 

 

ADD A,3

 

 

RZF

 

Z flag

0

 

1

0

 

A register

1101

 

0000

0000

SBC r,i

Subtract with carry immediate data i from r-register

Source Format:

SBC r,i

 

Operation:

r

r - i3 to i0 - C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OP-Code:

1

 

1

0

1

0

1

r1

r0

i3

i2

i1

i0

 

D40H to D7FH

 

MSB

 

 

 

 

 

 

 

 

 

 

LSB

 

Type:

II

 

 

 

 

 

 

 

 

 

 

 

 

 

Clock Cycles:

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Flag:

C – Set if a borrow is generated; otherwise, reset.

Z– Set if the result is zero; otherwise, reset. D – Not affected

I – Not affected

Description: Subtracts the carry flag and immediate data i from the r-register.

Example:

 

SBC A,9

 

 

SBC MY,0DH

 

A register

1000

 

1111

 

1111

 

Memory (MY)

1110

 

1110

 

0000

 

C flag

0

 

1

 

0

 

Z flag

0

 

0

 

1

76

EPSON

S1C6200/6200A CORE CPU MANUAL