[LispM-Hackers] load band help

[Carl Shapiro]

I have been trying to figure out the format of a load band, and have
been left terribly confused by some code in e3 which I have included
below:

(see band.cc, line 223)

  e3WordAddr e3Band::load(e3MemMap *m)
  {
  #ifdef NOTDEF
    dumpRegions();
  #endif

    e3Word dpmt = readWord(NUM_REGIONS + 9);
    e3u32  origin_address = dpmt.getPointer();

    ...

NUM_REGIONS is defined to be 2048.  I would very much like to know
what the corresponding constant on the Explorer is.  I suspect it may
be SI:SIZE-OF-REGION-ARRAYS, but I am short on compelling evidence.
The 9 that NUM_REGIONS is summed with confuses me even more.  I have
positively no idea why we seek that many words father into the band.

Have I missed a section of the SSDN where these aspects of load band
are discussed?