F2               1468 src/dps8/dps8_cpu.h #define F2 Fk [0]
F2                797 src/dps8/dps8_ins.c     putbits36_1  (& words[4], 31, cpu.du.F2);
F2                848 src/dps8/dps8_ins.c     cpu.du.F2       = getbits36_1  (words[4], 31);