Indirect Program Control With The Index Register; Program Loop Control; The Mechanics; Index Register Storage And Recall - HP -15C Owner's Handbook Manual

Section 10: The Index Register and Loop Control

Indirect Program Control With the Index Register

The V key is used for all forms of indirect program control other than
indirect register addressing. Hence, V (not %) is used for indirect
program branching, indirect display format control, and indirect flag
control.

Program Loop Control

Program loop counting and control can be carried out in the HP-15C by any
storage register: R
Loop control can also be carried out indirectly with %.

The Mechanics

Both V and % can be used in abbreviated key sequences, omitting the
preceding ´ prefix (as explained on page 78).

Index Register Storage and Recall

Direct. O V and l V. Storage and recall between the X-
register and the Index register operate in the same manner as with other data
storage registers (page 42).
Indirect. O (or l) % stores into (or recalls from) the data storage
register whose number is addressed by the integer portion of the value (0 to
65) in the Index register. See the table below and on the next page.
If R
contains:
I
± 0
⋮
9
10
11
⋮
19
20
 0 only.
*For R
I
through R , R
0 9 .0
Indirect Addressing
% will address:
R
0
⋮
R
9
R
.0
R
.1
⋮
R
.9
R
20
through R , or the Index register (V).
.9
t V or G V will
transfer to:*
´ b 0
⋮
´ b 9
" " .0
" " .1
⋮
´ b .9
" A
"
(Continued on next page.)
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