LSI LSI53C1000, Technical Manual

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Transfer Control Instructions 5-27
5.5 Transfer Control Instructions
This section describes transfer control instructions for the first Dword,
second Dword, and third Dword.
5.5.1 First Dword
This section describes the first Dword of the Transfer Control Instruction
register.
Figure 5.9 Transfer Control Instructions - First Dword
IT[1:0] Instruction Type -
Transfer Control Instruction
[31:30]
OPC[2:0] Opcode [29:27]
This 3-bit field specifies the type of transfer control
instruction to execute. All transfer control instructions can
be conditional. They can be dependent on a true/false
comparison of the ALU Carry bit, or a comparison of the
SCSI information transfer phase with the Phase field,
and/or a comparison of the First Byte Received with the
Data Compare field. Each instruction can operate in the
initiator or target mode.
Jump Instruction
The LSI53C1000 can do a true/false comparison of the
ALU carry bit, or compare the phase and/or data as
defined by the Phase Compare, Data Compare and
True/False bit fields. If the comparisons are true, it loads
31 30 29 27 26 24 23 22 21 20 19 18 17 16 15 8 7 0
DCMD Register DBC Register
IT[1:0] OPC[2:0] SCSIP[2:0] RA J CT IF TF CD CP VP MC DC
OPC2 OPC1 OPC0 Instruction Defined
0 0 0 Jump
0 0 1 Call
0 1 0 Return
0 1 1 Interrupt
1 x x Reserved