3 INSTRUCTION SET

RETS

Return then skip an instruction

 

Source Format:

RETS

 

 

 

 

 

 

 

Operation:

PCSL M(SP), PCSH

M(SP+1), PCP

M(SP+2), SP SP + 3, PC PC + 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OP-Code:

1

1

1

1

1

1

0

1

1

1

1

0

 

FDEH

 

MSB

 

 

 

 

LSB

 

Type: VI

Clock Cycles: 12

Flag: C – Not affected

Z– Not affected D – Not affected I – Not affected

Description: Jumps to the return address that was pushed onto the stack when the subroutine was called and then skips one instruction.

Example:

 

RETS

 

PCP

0110

0000

 

PCS

1001 0000

0000 0111

 

SP

B0

B3

 

Memory (SP)

0110

0110

 

Memory (SP+1)

0000

0000

 

Memory (SP+2)

0000

0000

RLC r

Rotate r-register left with carry

 

 

 

Source Format:

RLC r

 

 

 

 

 

 

 

 

 

 

Operation:

d3

d2, d2

d1, d1

d0, d0

C, C

d3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OP-Code:

1

 

0

1

0

1

1

1

1

r1

r0

r1

r0

 

AF0H to AFFH

 

MSB

 

 

 

 

 

 

 

 

 

 

LSB

 

Type:

IV

 

 

 

 

 

 

 

 

 

 

 

 

 

Clock Cycles:

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Flag:

C – Set when the high-order bit of the r-register is 1; otherwise, reset.

Z– Not affected D – Not affected I – Not affected

Description: Shifts the contents of the r-register one bit to the left. The high-order bit is shifted into the carry flag and the carry bit becomes the low-order bit of the r-register.

 

C

r-register

 

 

 

C

r-register

 

C

 

d3

d2

d1

d0

 

 

 

d3

d2

d1

d0

C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Example:

 

 

RLC A

 

A register

0011

 

0111

 

C flag

1

 

0

 

 

 

 

 

74

EPSON

S1C6200/6200A CORE CPU MANUAL