We now have a record that represents the actions taken in executing an
instruction, and a process that computes that for the incoming
instruction. We no longer have 'current' or 'r.cur_instr', instead
things like the destination register are put into r.e in the first
cycle of an instruction and not reinitialized in subsequent busy
cycles.
For mfspr and mtspr, we now decode "slow" SPR numbers (those SPRs that
are not stored in the register file) to a new "spr_selector" record
in decode1 (excluding those in the loadstore unit). With this, the
result for mfspr is determined in the data path.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Besides the overflow and status carry bits, XER has 18 bits which need
to retain the value written by mtxer (in case software wants to
emulate the move-assist instructions (lswi, lswx, stswi, stswx).
Until now these bits (and others) have been stored in the GPR file as
a "fast" SPR, but this causes complications because XER is not really
a fast SPR.
Instead, we now store these 18 bits in the 'ctrl' signal, which exists
in execute1. This will enable us to simplify the data path in future,
and has the added bonus that with a little bit of plumbing, we can get
the full XER value printed when dumping registers at the end of a
simulation.
Therefore this changes scripts/run_test.sh to remove the greps which
exclude XER from the comparison of actual and expected register
results.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Simplify the flow control by stalling the whole upstream pipeline when
a stage can't proceed, instead of trying to let each stage progress
independently when it can.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
While these signals should only be read when valid is true, they
are only a small number of bits and we want to reduce the amount of
U/X state bouncing around the chip.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
decode1 has a lot of logic that uses i_out.insn without first looking at
i_iout.valid. Play it safe and never output X state.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
While we should only look at this when d_out.valid = 1, we may as remove
some U state across interfaces.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
While this is not an issue in VHDL, I noticed this when running
a script over the source and we may as well fix it.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
While trying to reduce U/X state issues, I notice that our BSS is not
being initialised in the hello world test.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
These instructions are similar to those at
https://ozlabs.org/~joel/microwatt/README
except they describe how to build the artifacts from scratch instead of
downloading them.
Signed-off-by: Joel Stanley <joel@jms.id.au>
The SoC defaults to using the uart16550 so provide instructions on how
to fetch that library when seetting up fusesoc.
Also remove the text about a working directory; fusesoc doesn't need
one.
Signed-off-by: Joel Stanley <joel@jms.id.au>
log2ceil() returns the number of bits required to store a value, so we
need to pass in memory_size-1, not memory_size.
Every other user of log2ceil() gets this right.
Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
Setting icache to be privileged and accessing physical memory directly.
And set big_endian to 0 to correspond to the testbench result.
Signed-off-by: Tianrui Wei <tianrui@tianruiwei.com>
Revert to linking dynamically by default, can statically link with
`make STATIC_URJTAG=1`
Fixes#351
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
We've had these for a while now:
- D/I cache
- GPR bypassing
- Supervisor state (and can boot linux)
We still need Vector/VMX/VSX (and probably some other things)
Signed-off-by: Michael Neuling <mikey@neuling.org>
This is necessary for the upcoming Arctic Tern system enablement,
since Arctic Tern uses two DRAM devices and a separate clock line
is routed to each device. LiteX handles this behavior correctly,
therefore we assume other hardware exists that uses a similar
DRAM clock design.
Updates from Mikey to fix some compile issues.
Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
