Avago Technologies LSI53C895A User Manual

Page 249

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Transfer Control Instructions

5-27

Jump Instruction

The LSI53C895A 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 DSP

register now contains the address of the next instruction.

If the comparisons are false, the LSI53C895A fetches the
next instruction from the address pointed to by the

DMA

SCRIPTS Pointer (DSP)

register, leaving the instruction

pointer unchanged.

Call Instruction

The LSI53C895A 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

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 LSI53C895A executes a Call instruction, the
instruction pointer contained in the 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.

If the comparisons are false, the LSI53C895A fetches the
next instruction from the address pointed to by the DSP
register and the instruction pointer is not modified.

Return Instruction

The LSI53C895A 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

DMA SCRIPTS

Pointer (DSP)

register with the contents of the

DMA

SCRIPTS Pointer Save (DSPS)

register. That address

value becomes the address of the next instruction.

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