Avago Technologies LSI53C1010R User Manual
Page 280
5-32
SCSI SCRIPTS Instruction Set
Version 2.2
Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
RA
Relative Addressing Mode
23
When this bit is set, the 24-bit signed value in the
DMA SCRIPTS Pointer Save (DSPS)
register is used as
a relative offset from the current
address, which is pointing
to the next instruction and not the one currently
executing. The relative mode does not apply to
Return and Interrupt SCRIPTS.
Jump/Call an Absolute Address
Start execution at the new absolute address.
Jump/Call a Relative Address
Start execution at the current address plus (or minus) the
relative offset.
The SCRIPTS program counter is a 32-bit value pointing
to the SCRIPTS currently under execution by the
LSI53C1010R. The next address is formed by adding the
32-bit program counter to the 24-bit signed value of the last
24 bits of the Jump or Call instruction. Because it is signed
(twos complement), the jump can be forward or backward.
MSG
C/D
I/O SCSI Phase
0
0
0
ST Data-Out
0
0
1
ST Data-In
0
1
0
Command
0
1
1
Status
1
0
0
DT Data-Out
1
0
1
DT Data-In
1
1
0
Message-Out
1
1
1
Message-In
Command
Condition Codes
Absolute Alternate Address
Command
Condition Codes
Don’t Care
Alternate Jump Offset