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

Wei Song ws327 at cam.ac.uk
Thu Jul 20 17:24:14 BST 2017

I see. The BBL in pk is left there for Spike (the instruction set 
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 
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.


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 
> <mailto: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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