HP HP-67 - Section 12: Using the I-Register for Indirect Control

Section 12
Using the I-Register
for Indirect Control
You have seen how the value in the I-register can be altered using
the (sT1], , (52) and operations. But the value contained in
the I-register can also be used to control other operations. The [f
(indirect) function combined with certain other functions allows you
to control those functions using the current number in the I-register.
[@ uses the number stored in the I-register as an address.
The indirect operations that can be controlled by the I-register are:
EE3 (@, when the number in the I-register is O through 9, changes
display formatting so that the number in the display contains the
number of decimal places specified by the current number in the
I-register.
(@, when the number in the I-register is O through 25, stores
the value that is in the display in the primary or secondary storage
register addressed by the current number in the I-register.
[@, when the number in the I-register is O through 25, recalls
the contents of the primary or secondary storage register addressed
by the current number in the I-register.
[@,E50 & [, 58 £ [@, and £ & (@, when the number
in the I-register is O through 25, perform storage register arithmetic
upon the contents of the primary or secondary storage register
addressed by the current number in the I-register.
B (EZ0), when the number in the I-register is O through 25, in-
crements
(adds
1
to)
the
contents
of
the
primary
or
secondary
storage
register
addressed
by
the
current
number
in
the
I-register.
In
a
running
program,
one
step
is
skipped
if
the
contents
of
the
addressed
register
are
then
zero.
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