HP HP-16C - Section 9: Program Branching and Controls; Further Information; Subroutines

92 Section 9: Program Branching and Controls
Keystrokes Display
(9](#8] 012- 43 7 Sumsthebitsin the
X-register.
013- 40 Adds this sum to least
significant part of
current checksum. Might
set carry flag.
(xxy] 014- 34 Brings most significant
part of current checksum
into X.
0 015- 0 Places0inX.
(g](RLC] 016- 43 C PlacesalintoXifa
carry was generated in
the preceding addition.
017- 40 Adds carry bit to most
significant part of
checksum.
(xxy] 018- 34 Returns least significant
part of checksum to X.
(9](bsz] 019- 4323 Decrements the current
register number stored in
R;.
0 020- 22 0 Ifregister numberinR;
is not yet zero, then
continues with loop.
(9](RTN] 021- 43 21
Now, calculate an updated checksum (bit summation) given the
following 4-bit hexadecimal values in R; through Ry:
Ry: A Ry B Rs: 3 Ry A Re: D
Rz: 7 R4: 1 RGI D RBI 2 RA: 6
Keystrokes Display ([STATUS]: 0-04-0000)
(e](P/R] Returns to Run mode.
A 1 A h Storethe above values in
: . R, through Rj,.
6 (STOJA 6 h