*LDB, *DBP

[JONL at MIT-MC (Jon L White)]

    Date: 18 September 1980 04:06-EDT
    BTW I notice that the functions *ldb and *dpb take the byte
    specifcation shifted left by 30 (octal).  This causes (ldb x y)
    to expand into (*ldb (lsh x 30) y).  This seems pretty gratuitous
    to me since it only takes one instruction to have *ldb and *dpb
    do the lsh themselves.  (*ldb contains an unnecessary move anyway!)
*LDB and *DPB take a pre-shifted argument so that when, for example,
"x" is a constant, the call becomes  (*ldb <x>_30 y), and the executable
sequence then doesn't include the LSH;  this in fact is the case worth
optimizing.