Avago Technologies LSI53C1010 - Manual (Page 68)

3-28 The SCSI SCRIPTS Processor Instruction Set
Example JUMP Do_Next_Command WHEN COMMAND
JUMP Data_Check, IF DATA_IN AND 0x80 MASK 0x7F
IF Causes the SCRIPTS processor to immediately check for a
valid SCSI bus phase. IF should not be used when comparing
for a phase as this could yield unpredictable results. The only
exception is using a WHEN conditional just prior to the IF
conditional for any given sequence of phase checks.
NOT Negates the comparison. It clears the True bit if present,
otherwise the True bit is set.
Phase Specifies the Message, Command/Data, and Input/Output bit
values that identify the SCSI phase in the instruction. The
desired phase value is compared with the actual values of the
SCSI phase lines before the SCRIPTS processor performs the
instruction. This field is only valid for the initiator mode and
should not be used in the target mode.
ATN Is used to indicate that a jump should take place based on the
state of the initiator SATN/ signal. This field is valid only for
target mode and should not be used in the initiator mode.
data Represents an 8-bit value that is stored in the data field of the
instruction. In addition, this keyword indicates that the Compare
Data bit is set.
MASK Represents an 8-bit value that is stored in the mask field of the
instruction. Any bit that is set in the mask causes the
corresponding bit in the data byte to be ignored at the time of
the comparison.
CARRY Indicates that a jump should take place based on the value of
the carry bit in the ALU.
Figure 3.8 JUMP Format
31 30 29 27 26 24 23 22 21 20 19 18 17 16 15 8 7 0
DCMD Register DBC Register
Instr
Type
Opcode
SCSI
Phase
Rel
Addr
R
Carry
Test
R True
Comp
Data
Comp
Phase
Wait Mask Data
1 0 0 0 0 x x x x 0 0 0 x x x x x x x x x x x x x x x x x x x x
31 0
DSPS Register
Destination Address
x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x