Error announced by xwb_crossbar, when the block contains only a blackbox.

[wzab]

When I try to generate the Wishbone fabric containing only a single blackbox,like below:

<sysdef top="MAIN">
<constant name="NEXTERNS" val="4" />
<constant name="NSEL_BITS" val="3" />
<constant name="NSEL_MAX" val="(1 &lt;&lt; NSEL_BITS)-1" />
<!-- include block1.xml -->
<block name="MAIN">
  <blackbox name="EXTHUGE" type="HTEST" addrbits="16" />
</block>
</sysdef>

it results in an error:

ghdl -e -g --mb-comments  --std=93c -fexplicit --ieee=standard wb_test_top_tb ./wb_test_top_tb --unbuffered --stop-time=5000ns --wave=wb_test_top_tb.ghw  
general-cores/modules/wishbone/wb_crossbar/xwb_crossbar.vhd:107:7:@0ms:(assertion failure): Address space smaller than a wishbone register; slave #0[0x10000/0x1fffe]
./wb_test_top_tb:error: assertion failed
./wb_test_top_tb:error: error during elaboration
make: *** [Makefile:43: wb_test_top_tb.ghw] Error 1

The version that shows the problem is available via tag demo-bug1 in the repository, in directory test.

Adding just a single additional (in addition to VER & ID) register cures the problem.