HP -16C Owner's Handbook Manual page 66

64 Section 6: Memory and Storage
available for storage), then 101 storage registers(R, to Ry,,) are
available, since 203/2 = 101.5 and half registers are not available
for data storage.
Given a word size of 16, the configuration of memory allocation
would look like this with the first recorded program line:
Storage Registers (16 bits each)
Ro
R,
Rg
Directly Ra
addressable <
registers
Re
R.o
. R
(R20,) R32
(Rea, ) R1oo
Half register left
(not usablz2).
Program Memory
001-instruction
002-
003-
004-
005-
006-
007-
Lines 002 to 007
are available but
unoccupied.
These 3V2 registers
(seven bytes) are
converted to seven
lines of program
memory when the first
program instruction is
recorded.
When the eighth program instruction is recorded, another 3%
registers (seven bytes) will be converted to program memory. This