cp1_cntl.vhd
The Register Read/Writeback control for all registers associated with
the MOVI2S, MOVS2I instructions. This essentially acts likes
a coprocessor instruction and we want to keep this register decoding,
enabling separate from the GPR registers. We call this 'cp1_cntl'
for coprocessor 1 control
Adding another special register will only require this logic to be
be modifed; the normal GPR decode/exe/mem/write logic will remain the same
Warning!! During MOVI2S, NO FORWARDING is done for the new value of
the special purpose register value!!! These instructions are not used enough
to warrant the extra complexity. During MOVS2I, normal GPR destination
forwarding is done
C_IAR_oe
This signal is the output enable signal for the
C_IAR register in the interrupt block
IAR_oe
This is the output enable of the IAR register
which is the source of input to the program
counter
IMSK_oe
This signal is the output enable signal for the
IMSK register in the interrupt block
imsk_load
This is the load enable signal of the IMSK register
in the interrupt block