<s>
TI	B-Language
BASIC	I-Language
is	O
an	O
ANSI-compliant	O
BASIC	O
programming	O
language	O
interpreter	B-Application
built	O
into	O
the	O
1979	O
Texas	B-Device
Instruments	I-Device
TI-99/4	I-Device
home	O
computer	O
and	O
its	O
improved	O
1981	O
version	O
,	O
the	O
TI-99/4A	B-Device
.	O
</s>
<s>
In	O
contrast	O
to	O
most	O
BASICs	O
found	O
on	O
contemporary	O
microcomputers	B-Architecture
,	O
TI	B-Language
BASIC	I-Language
does	O
not	O
trace	O
its	O
history	O
to	O
Microsoft	B-Language
BASIC	I-Language
,	O
but	O
was	O
instead	O
a	O
TI-developed	O
interpreter	B-Application
following	O
the	O
emerging	O
Minimal	O
BASIC	O
standard	O
being	O
created	O
by	O
ANSI	O
and	O
ECMA	O
.	O
</s>
<s>
This	O
was	O
,	O
in	O
turn	O
,	O
based	O
on	O
the	O
original	O
Dartmouth	B-Language
BASIC	I-Language
from	O
the	O
1960s	O
.	O
</s>
<s>
There	O
are	O
a	O
number	O
of	O
differences	O
,	O
sometimes	O
subtle	O
,	O
between	O
TI	B-Language
BASIC	I-Language
and	O
the	O
more	O
common	O
MS	O
varieties	O
.	O
</s>
<s>
Minimal	O
BASIC	O
lacks	O
a	O
number	O
of	O
features	O
that	O
are	O
commonly	O
found	O
on	O
contemporary	O
BASICs	O
,	O
and	O
Texas	O
Instruments	O
later	O
introduced	O
the	O
TI	B-Language
Extended	I-Language
BASIC	I-Language
cartridge	B-Protocol
that	O
enhanced	O
the	O
functionality	O
accessible	O
to	O
BASIC	O
users	O
.	O
</s>
<s>
As	O
was	O
common	O
on	O
home	O
computers	O
,	O
TI	B-Language
BASIC	I-Language
was	O
used	O
not	O
only	O
for	O
programming	O
but	O
also	O
as	O
a	O
thin	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
On	O
top	O
of	O
Minimal	O
BASIC	O
,	O
TI	O
added	O
commands	O
for	O
text	O
,	O
graphics	O
,	O
and	O
basic	O
file	O
operations	O
like	O
recording	O
to	O
tape	B-Device
or	O
any	O
other	O
file	O
system	O
.	O
</s>
<s>
Due	O
to	O
the	O
specifics	O
of	O
the	O
TI-99	B-Device
platform	O
,	O
TI	B-Language
BASIC	I-Language
was	O
most	O
notable	O
for	O
its	O
extremely	O
slow	O
performance	O
,	O
roughly	O
half	O
that	O
of	O
common	O
machines	O
,	O
but	O
conversely	O
sported	O
high	O
numerical	O
accuracy	O
.	O
</s>
<s>
The	O
TI-99	B-Device
was	O
based	O
on	O
the	O
TMS9900	B-General_Concept
microprocessor	B-Architecture
,	O
a	O
16-bit	O
design	O
that	O
was	O
originally	O
built	O
to	O
provide	O
a	O
single-chip	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	O
)	O
in	O
low-end	O
models	O
of	O
their	O
TI-990	B-Device
minicomputer	B-Architecture
lineup	O
.	O
</s>
<s>
The	O
TMS9900	B-General_Concept
was	O
also	O
suitable	O
for	O
use	O
in	O
a	O
microcomputer	B-Architecture
,	O
but	O
at	O
that	O
time	O
the	O
rest	O
of	O
the	O
support	O
chips	O
required	O
to	O
build	O
a	O
complete	O
computer	O
were	O
invariably	O
8-bit	O
,	O
and	O
this	O
included	O
TI	O
's	O
wide	O
catalog	O
of	O
such	O
chips	O
.	O
</s>
<s>
In	O
a	O
minicomputer	B-Architecture
,	O
16-bit	O
support	O
systems	O
were	O
built	O
up	O
of	O
many	O
individual	O
chips	O
,	O
but	O
this	O
was	O
not	O
suitable	O
for	O
a	O
low-cost	O
product	O
.	O
</s>
<s>
TI	O
thus	O
adopted	O
the	O
solution	O
of	O
making	O
the	O
machine	O
mostly	O
8-bit	O
and	O
connecting	O
the	O
various	O
support	O
chips	O
to	O
this	O
8-bit	O
bus	O
,	O
with	O
the	O
TMS9900	B-General_Concept
reading	O
the	O
bus	O
twice	O
to	O
produce	O
a	O
16-bit	O
value	O
.	O
</s>
<s>
The	O
TMS9900	B-General_Concept
's	O
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
was	O
based	O
on	O
16-bit	O
opcodes	B-Language
,	O
meaning	O
that	O
programs	O
would	O
generally	O
be	O
twice	O
as	O
large	O
as	O
they	O
would	O
be	O
on	O
an	O
8-bit	O
machine	O
.	O
</s>
<s>
To	O
address	O
this	O
,	O
TI	O
created	O
an	O
8-bit	O
virtual	B-Architecture
machine	I-Architecture
with	O
its	O
own	O
language	O
or	O
intermediate	B-Application
representation	I-Application
known	O
as	O
the	O
"	O
Graphic	O
Programming	O
Language	O
"	O
,	O
or	O
GPL	O
,	O
that	O
allowed	O
programs	O
to	O
be	O
written	O
in	O
a	O
more	O
compact	O
format	O
.	O
</s>
<s>
The	O
downside	O
to	O
this	O
approach	O
is	O
that	O
every	O
GPL	O
instruction	O
had	O
to	O
be	O
converted	O
on	O
the	O
fly	O
into	O
one	O
or	O
more	O
underlying	O
TMS9900	B-General_Concept
instructions	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
TI	B-Language
BASIC	I-Language
had	O
poor	O
performance	O
;	O
on	O
common	O
benchmarks	O
of	O
the	O
era	O
,	O
the	O
TI-99	B-Device
generally	O
ran	O
half	O
as	O
fast	O
as	O
8-bit	O
machines	O
like	O
the	O
Commodore	B-Device
PET	I-Device
or	O
Apple	B-Device
II	I-Device
.	O
</s>
<s>
For	O
instance	O
,	O
running	O
the	O
Byte	B-Language
Sieve	I-Language
in	O
BASIC	O
took	O
3960	O
seconds	O
in	O
TI	B-Language
BASIC	I-Language
,	O
while	O
the	O
same	O
test	O
in	O
Applesoft	B-Language
BASIC	I-Language
on	O
the	O
Apple	B-Device
II	I-Device
,	O
ostensibly	O
a	O
much	O
slower	O
machine	O
,	O
took	O
2806	O
seconds	O
,	O
about	O
30%	O
faster	O
that	O
the	O
TI	O
.	O
</s>
<s>
Unlike	O
most	O
BASICs	O
of	O
the	O
era	O
,	O
TI	B-Language
BASIC	I-Language
did	O
not	O
provide	O
a	O
full-screen	O
editor	O
.	O
</s>
<s>
It	O
used	O
a	O
prompt	O
to	O
indicate	O
the	O
current	O
new	O
line	O
in	O
immediate	B-Application
mode	I-Application
,	O
as	O
opposed	O
to	O
the	O
more	O
common	O
.	O
</s>
<s>
Line	O
entry	O
was	O
aided	O
by	O
the	O
command	O
,	O
available	O
only	O
in	O
immediate	B-Application
mode	I-Application
,	O
which	O
entered	O
ascending	O
line	O
numbers	O
,	O
and	O
,	O
which	O
renumbered	O
an	O
existing	O
program	O
.	O
</s>
<s>
TI	B-Language
BASIC	I-Language
also	O
included	O
a	O
number	O
of	O
debugging	O
commands	O
.	O
</s>
<s>
Unlike	O
,	O
the	O
exit	O
to	O
immediate	B-Application
mode	I-Application
did	O
not	O
occur	O
on	O
the	O
line	O
where	O
appeared	O
,	O
but	O
on	O
the	O
lines	O
referred	O
to	O
.	O
</s>
<s>
For	O
instance	O
,	O
would	O
cause	O
the	O
program	O
to	O
exit	O
to	O
immediate	B-Application
mode	I-Application
whenever	O
it	O
moved	O
to	O
line	O
130	O
.	O
</s>
<s>
The	O
ANSI-compatible	O
statements	O
of	O
TI	B-Language
BASIC	I-Language
are	O
.	O
</s>
<s>
is	O
not	O
valid	O
in	O
TI	B-Language
BASIC	I-Language
.	O
</s>
<s>
This	O
can	O
easily	O
lead	O
to	O
off-by-one	B-Error_Name
errors	I-Error_Name
if	O
the	O
conversion	O
is	O
not	O
careful	O
about	O
changing	O
the	O
sense	O
of	O
the	O
boolean	O
comparison	O
.	O
</s>
<s>
TI	B-Language
BASIC	I-Language
did	O
,	O
however	O
,	O
support	O
the	O
clause	O
:	O
</s>
<s>
This	O
precluded	O
its	O
use	O
as	O
a	O
statement	O
separator	O
,	O
a	O
concept	O
that	O
TI	B-Language
BASIC	I-Language
did	O
not	O
have	O
.	O
</s>
<s>
Due	O
to	O
the	O
way	O
BASIC	O
interpreters	B-Application
work	O
,	O
-based	O
loops	O
can	O
be	O
sped	O
up	O
significantly	O
by	O
combining	O
code	O
onto	O
a	O
single	O
line	O
,	O
which	O
avoids	O
having	O
to	O
search	O
through	O
the	O
program	O
for	O
line	O
numbers	O
.	O
</s>
<s>
For	O
instance	O
,	O
clears	O
the	O
screen	B-Device
,	O
and	O
returns	O
the	O
keycode	O
of	O
the	O
currently	O
pressed	O
key	O
on	O
the	O
keyboard	O
.	O
</s>
<s>
The	O
language	O
lacked	O
PEEK	B-Language
and	I-Language
POKE	I-Language
so	O
there	O
was	O
no	O
way	O
to	O
create	O
new	O
CALLable	O
code	O
within	O
BASIC	O
,	O
to	O
do	O
this	O
one	O
would	O
require	O
the	O
TI	O
Editor/Assembler	O
,	O
the	O
TI	O
Mini	O
Memory	O
cartridge	B-Protocol
which	O
included	O
a	O
small	O
assembler	B-Language
,	O
or	O
by	O
using	O
Extended	O
BASIC	O
.	O
</s>
<s>
Unlike	O
Microsoft	B-Language
BASICs	I-Language
,	O
which	O
used	O
,	O
,	O
,	O
and	O
for	O
manipulating	O
strings	O
,	O
TIBASIC	O
used	O
the	O
ANSI-compliant	O
and	O
.	O
</s>
<s>
TI	B-Language
BASIC	I-Language
was	O
located	O
in	O
the	O
system	O
's	O
internal	O
ROMs	O
.	O
</s>
<s>
In	O
1981	O
,	O
TI	O
released	O
a	O
plug-in	O
ROM	B-Protocol
cartridge	I-Protocol
that	O
added	O
additional	O
functions	O
to	O
the	O
existing	O
code	O
,	O
improving	O
the	O
language	O
in	O
a	O
number	O
of	O
ways	O
.	O
</s>
<s>
Confusingly	O
,	O
as	O
a	O
statement	O
with	O
two	O
colons	O
was	O
also	O
possible	O
in	O
TI	B-Language
BASIC	I-Language
,	O
for	O
instance	O
,	O
,	O
which	O
would	O
output	O
"	O
A	O
"	O
,	O
a	O
blank	O
line	O
and	O
then	O
"	O
B	O
"	O
,	O
so	O
these	O
statements	O
required	O
a	O
space	O
to	O
be	O
added	O
in	O
Extended	O
BASIC	O
,	O
.	O
</s>
<s>
The	O
last	O
three	O
statements	O
are	O
used	O
for	O
structured	B-Language
programming	I-Language
,	O
allowing	O
the	O
creation	O
of	O
named	O
subroutines	O
.	O
</s>
<s>
When	O
equipped	O
with	O
the	O
TI	O
Speech	B-Application
Synthesizer	I-Application
,	O
TI	B-Language
Extended	I-Language
BASIC	I-Language
users	O
could	O
also	O
generate	B-Application
speech	I-Application
from	O
a	O
predefined	O
vocabulary	O
as	O
easily	O
as	O
writing	O
text	O
on-screen	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
following	O
line	O
of	O
text	O
would	O
cause	O
the	O
speech	B-Application
synthesizer	I-Application
to	O
identify	O
the	O
computer	O
:	O
</s>
<s>
Using	O
a	O
word	O
not	O
included	O
in	O
the	O
speech	B-Application
synthesizer	I-Application
's	O
built-in	O
vocabulary	O
of	O
338	O
words	O
and	O
phrases	O
would	O
cause	O
it	O
to	O
slowly	O
spell	O
out	O
the	O
word	O
.	O
</s>
<s>
TI	O
's	O
Terminal	O
Emulator	O
II	O
cartridge	B-Protocol
provided	O
text-to-speech	B-Application
functionality	O
.	O
</s>
