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Avago Technologies LSI53C1010 User Manual

Page 73

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Instruction Descriptions

3-33

Example

JUMP Do_Next_Command WHEN COMMAND

JUMP Data_Check, IF DATA_IN AND 0x80 MASK 0x7F

Address

Is the location to which execution will be transferred if the
subroutine is called. If REL is used, Address is the offset from
the current DSP value.

WHEN

Forces the SCRIPTS engine to wait for a valid SCSI bus phase
before continuing. A valid phase is indicated by assertion of the
SREQ/ signal.

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.

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