The D flag bit is part of the cc flag bit register currently. But since it
is not being used any where in the implementation, it creates an unnecessary
dependency. Hence, it is being moved to a separate register.
This patch moves the ECF and EZF bits to individual registers (ecfBit and
ezfBit) and the CF and OF bits to cfofFlag registers. This is being done
so as to lower the read after write dependencies on the the condition code
register. Ultimately we will have the following registers [ZAPS], [OF],
[CF], [ECF], [EZF] and [DF]. Note that this is only one part of the
solution for lowering the dependencies. The other part will check whether
or not the condition code register needs to be actually read. This would
be done through a separate patch.
This is my best guess as far as what these should do. Other existing microops
use implicit registers, mul1s and mul1u for instance, so this should be ok.
The microop that loads the implicit DoubleBits register would fall into one
of the microop slots for moving to/from special registers.
There are no priviledge checks, so these instructions will all work in all
modes.
--HG--
extra : convert_revision : ff893eb569313d8aecbfffb47bcbd1c2d65cd393
This is stored in the integer register file so that it can be renamed, but it should be a misc reg.
--HG--
extra : convert_revision : eee48f24dd80b145f14427482047c4d8af2521ab
