Avago Technologies LSI53C1010 - Manual (Page 76)

3-36 The SCSI SCRIPTS Processor Instruction Set
Description The SCSI Jump instruction is a conditional jump to the destination
address, if the SCSI phase, data, or attention condition compares true
with the phase, data, or attention condition described in the instruction.
If the comparison is false, the SCRIPTS processor does not branch to
the destination but instead fetches the next instruction and continues
execution.
When the optional data field is used, it is compared to the SFBR. This
contains the most recent byte of any type of data that has been moved
into the SFBR register. The SCSI SCRIPTS program determines which
routine to execute next based on received data values. Using a series of
these compares, the algorithm processes complex sequences with no
intervention required by the external processor.
When the optional MASK keyword and its associated value are specified,
the SCRIPTS processor allows selective comparisons of bits within the
data byte. During the compare, any mask bits that are set will cause the
corresponding bit in the data byte to be ignored for the comparison.
Compare
Phase Compare current SCSI phase to SCSI phase field or SATN/.
This bit is set whenever the Phase operand is used.
0 - Do not compare phase
1 - Perform comparison
Wait Wait for valid phase. This bit is set by the WHEN operand in
the instruction, and cleared by the IF operand.
0 - Perform comparison immediately
1 - Wait for valid phase (SREQ/ asserted by target)
Mask An 8-bit field that is used to mask the value in SFBR before the
comparison with the data field in the instruction takes place. As
a result of this operation, any bits that are set will cause the
corresponding bit in the data byte to be ignored. If this field is
not specified, a mask of 0x00 is used.
Data An 8-bit field that is compared with the incoming data after the
mask operation of the mask byte takes place. Comparison
indicates either an equal or not equal condition. If the Data field
is not specified, the Compare Data bit is cleared and 0x00 is
coded for both the mask and data bytes.
Destination
Address A 32-bit address (or 24-bit offset) where execution will continue
if the jump is executed.