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

 

 

 

 

Jump Instruction

The LSI53C810A 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, then it loads the DMA SCRIPTS Pointer (DSP) register with the contents of the DMA SCRIPTS Pointer Save (DSPS) register. The DMA SCRIPTS Pointer (DSP) register now contains the address of the next instruction.

If the comparisons are false, the LSI53C810A fetches the next instruction from the address pointed to by the DMA SCRIPTS Pointer (DSP) register, leaving the instruction pointer unchanged.

Call Instruction

The LSI53C810A 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, then it loads the DMA SCRIPTS Pointer (DSP) register with the contents of the DMA SCRIPTS Pointer Save (DSPS) register and that address value becomes the address of the next instruction.

When the LSI53C810A executes a Call instruction, the instruction pointer contained in the DMA SCRIPTS Pointer (DSP) register is stored in the Temporary (TEMP) register. Since the TEMP register is not a stack and can only hold one Dword, nested call instructions are not allowed.

6-28

Instruction Set of the I/O Processor

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LSI 53C810A technical manual Jump Instruction, Call Instruction