Commit Graph

7 Commits (4174cd8e9393445e859974656c3560a1c0bff388)

Author SHA1 Message Date
Anton Blanchard b57325ce29 Merge branch 'divider' of https://github.com/paulusmack/microwatt 5 years ago
Anton Blanchard 5a6f8d26d1 Rename OP_SUBFC -> OP_SUBFE, OP_ADDC -> OP_ADDE
These were somewhat badly named.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Paul Mackerras d5bc6c8824 Add a divider unit and a testbench for it
This adds a divider unit, connected to the core in much the same way
that the multiplier unit is connected.  The division algorithm is
very simple-minded, taking 64 clock cycles for any division (even
32-bit division instructions).

The decoding is simplified by making use of regularities in the
instruction encoding for div* and mod* instructions.  Instead of
having PPC_* encodings from the first-stage decoder for each of the
different div* and mod* instructions, we now just have PPC_DIV and
PPC_MOD, and the inputs to the divider that indicate what sort of
division operation to do are derived from instruction word bits.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
Anton Blanchard 9867fb6149 Add a decode for the nop instruction
We want these to go out without any GPR dependencies, so add
a specific entry in decode for them.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard a2df2a10a2 Remove sim console
We can force all existing code to use the UART console
by passing 0 in bit zero of the sim config register.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 9687034d78 Add a decode bit to mark an instruction as single through the pipeline
This is used by the pipelining patches. Mark everyone as single through
the pipeline to start.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
Anton Blanchard 5a29cb4699 Initial import of microwatt
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago