Converting enum code (integer) to EnumItem

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Hi guys,

I have been working with MyHDL for a few months and I find it really great. Thanks for bringing joy of hardware programing back :wink:

Today I’ve revisited an issue I gave up in the past and I still can’t convince myself there isn’t a nice way of doing.

I have a protocol implemented in FPGA where I use MyHDL for the full development cycle, simulation, conversion to VHDL and then syntesis to Lattice device. Within this protocol I have a simple “command” field, for which I used enum so I can see pretty names on simulation. Example:

t_CMD = enum("NONE", "RD", "WR", "ID", "PROBE", "ADDR", encoding="binary")

When a “packet” is received, the integer code for the command is extracted from header with bit slicing like:

header = Signal(intbv(0)[16:])
(...)
cmd.next = CtrlCmds.getCmd(header[7:])

where cmd.next is expect to be like t_CMD.NONE (EnumItem type).

The problem lies in the “getCmd()” implementation… I can’t think of a good and syntetizable way of geting EnumItem back from integer code that is not an ugly sequence of if’s like:

def getCmd(val):
    if val == CMD_NONE:
        return t_CMD.NONE
    elif val == CMD_RD:
        return t_CMD.RD
    (...)

I have tried a few ideas, like iterating through enum reftype() and then using getattr(t_CMD, name) or preloading all t_CMD values to a list, but they all failed to convert. (although some work on simulation)

Am I missing some clever way of doing this lookup / type conversion?

Thanks!

Miguel