[lowrisc-dev] Untethered lowRISC: run bbl using Verilator

Grady Chen gchen at viosoft.com
Mon Jul 24 12:35:36 BST 2017

Hi Wei,

Thank you for your suggestion.
I will try to use UCB Rocket-chip.
But seems it doesn't have the following useful modules which make me easier
to run it on velece2 simulator:
grady at qt03:~/work/*lowrisc-chip*/src$ find . -name *.sv
grady at qt03:~/work*/lowrisc-chip*/src$ find . -name "*.cpp"

Are these modules still useful for UCB Rocket-chip?

Grady Chen

On Fri, Jul 21, 2017 at 12:24 AM, Wei Song <ws327 at cam.ac.uk> wrote:

> I see. The BBL in pk is left there for Spike (the instruction set
> simulator.)
> Depending on which board you are using (or does not matter for verilator),
> BBL can be found at fpga/board/<board>/bbl
> However, I must say, the BBL is really for FPGA demo, or Vivado
> simulation. I am not sure what would come up if it is simulated in
> verilator.
> I might have run Verilator simulation on it as well.
> If host interface is really what you want, I might suggest the Rocket-chip
> from UCB?
> So what is the specific reason for you to choose lowRISC?
> Anyway, tagged-memory-v0.1 does use a very old version of host interface.
> Note that it also needs different gcc compilers, one for newlib one for
> linux.
> And it runs only one a Zynq board (Zedboard). We do not support verilator
> simulation for that version either.
> -Wei
> On 20/07/2017 17:02, Grady Chen wrote:
> Hi Wei,
> The BBL, I got it from the following:
> git clone -b untether-v0.2 --recursive https://github.com/lowrisc/
> lowrisc-chip.git
> ls -l owrisc-chip/riscv-tools/riscv-pk/pk/bbl.c
> Which BBL should I use if I would like to run it by Verilator?
> I am using single core. Which version should I use if I would like to use
> host interface? tagged-v0.1?
> --
> Thanks,
> Grady Chen
> On Thu, Jul 20, 2017 at 11:06 PM, Wei Song <ws327 at cam.ac.uk> wrote:
>> Hello Grady,
>> As I have mentioned, we were trying to remove the host interface from the
>> SoC in order to make it standalone. The functions of the host interface is
>> very much reduced.
>> This means there is no more host side and software should not rely on the
>> host side to fulfill I/O functions or any functions really (except for exit
>> simulation).
>> So where does this BBL come from? We do not support the original BBL from
>> UCB or SiFive. The BBL in lowRISC should have been revised.
>> Is this host interface call is related to multicore and you have
>> configured to use multicore?
>> The 0.2v of lowRISC does not support multicore, I am afraid.
>> Thanks for the clarification,
>> Wei

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