
Transfer Control Instruction
6-27
Jump Instruction
The SYM53C895 can do a true/false comparison of the
ALU carry bit, or compare the phase and/or data as
dened by the Phase Compare, Data Compare and
True/False bit elds.
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 SYM53C895 fetches the
next instruction from the address pointed to by the DMA
SCRIPTS Pointer (DSP) register, leaving the instruction
pointer unchanged.
Call Instruction
The SYM53C895 can do a true/false comparison of the
ALU carry bit, or compare the phase and/or data as
dened by the Phase Compare, Data Compare, and
True/False bit elds.
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 SYM53C895 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 SYM53C895 fetches the
next instruction from the address pointed to by the DSP
register and the instruction pointer is not modied.
Return Instruction
The SYM53C895 can do a true/false comparison of the
ALU carry bit, or compare the phase and/or data as
dened by the Phase Compare, Data Compare, and
True/False bit elds.
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.