5 transfer control instructions, 1 first dword, Transfer control instructions – Avago Technologies LSI8751D User Manual
Page 222: First dword
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Instruction Set of the I/O Processor
6.5 Transfer Control Instructions
6.5.1 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 Initiator or Target mode.
Jump Instruction
The LSI53C875 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 the
register with the contents of the
register. The DSP
register now contains the address of the next instruction.
If the comparisons are false, the LSI53C875 fetches the
next instruction from the address pointed to by the
register, leaving the instruction
pointer unchanged.
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