Texas Instruments TI Programmable 57 User Manual

There is a family of instructions on your calculator designed to let you
build decision-making into your programs. The basic operation of this
family of instructions is similar — and they're quite easy to learn, but they
are also flexible enough to allow a great deal of programming power.
Basically when a conditional transfer key sequence is encountered in a
program, the calculator immediately compares two quantities: the
number in the display register (called x) and the number in a special test
or “t” register (called t). (The “'t’ or test register is just memory 70on your
calculator.) The calculator then asks one of 4 questions about how x and
t compare — depending on the program instruction you use:
EM isx = t? (Isx equal t?)
(NV) (2nd) BH = Isx # t? (Is x not equal t?)
(2né) EM = Isx => t? (Is x greater than or.equal to t?)
(iV) (2nd) EI = Isx < t? (Isx less than t?)
If the answer is yes, the program pointer goes on to the instruction
immediately following. If the answer is NO, the program pointer SKIPS the
instruction immediately following and continues.
Let's go through each of the conditional transfer instructions (and the
keys for using them) one at a time.
[xst] — THE “x EXCHANGE wiTH t” Key
When this key is pressed the contents of the display register and the "'t’’
register
(memory
7)
are
just
exchanged.
This
provides
a
convenient
method of getting any test, or t, value into the test register.
(You can also use the @ 7 key sequence, or simply the 7
sequence if it is appropriate in your program.)
[2nd]
—
Tue
“Is
x
Equat
To
t?”
Key
SEQUENCE
You
can
enter
this
key
sequence
while
in
“learn”
mode
to
Have
the
program
pointer
take
one
of
several
pathways
in
your
program.
When
the
program
pointer
comes
to
this
instruction
in
a
program,
the
calculator
compares
what's
in
the
display
register
(x)
and
what's
in
the
“t’’
register
(t)
and
asks:
Is
x
equal
to
t?
If
the
answer
is
yes,
the
calculator
goes
right
on
to
the
step
following
the
key
sequence.
If
no,
the
pointer
skips
whatever
instruction
follows
and
moves
on
to
the
next
instruction
and
continues.

Texas Instruments TI Programmable 57 Specifications

General

Brand	Texas Instruments
Model	TI Programmable 57
Category	Calculator
Language	English