Table 5.3 Read/Write Instructions (Cont.)

 

OpCode 111

OpCode 110

OpCode 101

Operator

Read-Modify-Write

Move to SFBR

Move from SFBR

 

 

 

 

100

AND data with register and

AND data with register and

AND data with SFBR and

 

place the result in the same

place the result in the SCSI

place the result in the

 

register. Syntax: “Move

First Byte Received (SFBR)

register. Syntax: “Move

 

RegA & data8 to RegA”

register. Syntax: “Move

SFBR & data8 to RegA”

 

 

RegA & data8 to SFBR”

 

 

 

 

 

1011

Shift register one bit to the

Shift register one bit to the

Shift the SFBR register one

 

right and place the result in

right and place the result in

bit to the right and place the

 

the same register. Syntax:

the SCSI First Byte

result in the register. Syntax:

 

“Move RegA SHR RegA”

Received (SFBR) register.

“Move SFBR SHR RegA”

 

 

Syntax: “Move RegA SHR

 

 

 

SFBR”

 

 

 

 

 

110

Add data to register without

Add data to register without

Add data to SFBR without

 

carry and place the result

carry and place the result in

carry and place the result in

 

in the same register.

the SCSI First Byte

the register. Syntax: “Move

 

Syntax: “Move RegA +

Received (SFBR) register.

SFBR + data8 to RegA”

 

data8 to RegA”

Syntax: “Move RegA + data8

 

 

 

to SFBR”

 

 

 

 

 

111

Add data to register with

Add data to register with

Add data to SFBR with carry

 

carry and place the result

carry and place the result in

and place the result in the

 

in the same register.

the SCSI First Byte

register. Syntax: “Move

 

Syntax: “Move RegA +

Received (SFBR) register.

SFBR + data8 to RegA with

 

data8 to RegA with carry”

Syntax: “Move RegA + data8

carry”

 

 

to SFBR with carry”

 

 

 

 

 

1. Data is shifted through the Carry bit and the Carry bit is shifted into the data byte. Miscellaneous Notes:

Substitute the desired register name or address for “RegA” in the syntax examples.

data8 indicates eight bits of data.

Use SFBR instead of data8 to add two register values.

5.6 Transfer Control Instructions

This section describes the Transfer Control Instructions. The configuration of the OpCode bits define which Transfer Control Instruction to perform.

Transfer Control Instructions

5-25

Page 225
Image 225
LSI 53C875A technical manual Transfer Control Instructions