setimmediatevalue doesnt work for signals wider than 32 bit

cocotb_test.tar.gz

See attached testcase for details.

It looks like setimmediatevalue does not take effect if the signal width is greater than 32.

I tried the following variation and all of them fail

        dut.inp_short63.setimmediatevalue(0)
        dut.inp_short64.setimmediatevalue(BinaryValue(value=0,bits=65).value)
        dut.inp.setimmediatevalue(BinaryValue(value='0x0', bits=1024))

The normal assignment statement works

dut.inp_short70 <= BinaryValue(value=0xffffffffffffffff,bits=71).value

[eric-wieser]

Here’s the bug:

// Value related functions
int VpiSignalObjHdl::set_signal_value(long value)
{
    FENTER
    s_vpi_value value_s;

    value_s.value.integer = value;
    value_s.format = vpiIntVal;

    s_vpi_time vpi_time_s;

    vpi_time_s.type = vpiSimTime;
    vpi_time_s.high = 0;
    vpi_time_s.low  = 0;

    // Use Inertial delay to schedule an event, thus behaving like a verilog testbench
    vpi_put_value(GpiObjHdl::get_handle<vpiHandle>(), &value_s, &vpi_time_s, vpiInertialDelay);
    check_vpi_error();

    FEXIT
    return 0;
}

int VpiSignalObjHdl::set_signal_value(double value)
{
    FENTER
    s_vpi_value value_s;

    value_s.value.real = value;
    value_s.format = vpiRealVal;

    s_vpi_time vpi_time_s;

    vpi_time_s.type = vpiSimTime;
    vpi_time_s.high = 0;
    vpi_time_s.low  = 0;

    vpi_put_value(GpiObjHdl::get_handle<vpiHandle>(), &value_s, &vpi_time_s, vpiInertialDelay);
    check_vpi_error();

    FEXIT
    return 0;
}

int VpiSignalObjHdl::set_signal_value(std::string &value)
{
    FENTER
    s_vpi_value value_s;

    std::vector<char> writable(value.begin(), value.end());
    writable.push_back('\0');

    value_s.value.str = &writable[0];
    value_s.format = vpiBinStrVal;

    // !!! this path is the only one that fails
    vpi_put_value(GpiObjHdl::get_handle<vpiHandle>(), &value_s, NULL, vpiNoDelay);
    check_vpi_error();

    FEXIT
    return 0;
}

set_signal_value(std::string &value) does not use vpiInertialDelay, unlike the others which do.

[eric-wieser]

Ah, this is probably #637 in a new and exciting form.

It only fails if the write happens before any events have been yielded.

This fails, but passes if do_wait is changed to True

import cocotb
from cocotb.triggers import Timer, RisingEdge, ReadOnly
from cocotb.regression import TestFactory

@cocotb.coroutinue()
def do_test(dut, do_wait=False):
    if do_wait:
        yield Timer(1)
    dut.inp.setimmediatevalue(0)
    yield RisingEdge(dut.done)
    assert dut.inp.value == 0
    yield ReadOnly()