<s>
In	O
computer	O
instruction	B-General_Concept
set	I-General_Concept
architectures	I-General_Concept
(	O
ISA	O
)	O
,	O
a	O
repeat	B-General_Concept
instruction	I-General_Concept
is	O
a	O
machine	B-Language
language	I-Language
instruction	I-Language
which	O
repeatedly	O
executes	O
another	O
instruction	O
a	O
fixed	O
number	O
of	O
times	O
,	O
or	O
until	O
some	O
condition	O
is	O
met	O
.	O
</s>
<s>
Since	O
it	O
is	O
an	O
instruction	O
that	O
operates	O
on	O
other	O
instructions	O
like	O
the	O
execute	B-General_Concept
instruction	I-General_Concept
,	O
it	O
has	O
been	O
classified	O
as	O
a	O
meta-instruction	O
.	O
</s>
<s>
The	O
Univac	B-Device
1103	I-Device
(	O
1953	O
)	O
includes	O
a	O
repeat	B-General_Concept
instruction	I-General_Concept
(	O
op	O
code	O
mnemonic	O
:	O
)	O
which	O
executes	O
the	O
following	O
instruction	O
a	O
fixed	O
number	O
of	O
times	O
,	O
possibly	O
incrementing	O
one	O
or	O
both	O
of	O
the	O
address	O
fields	O
of	O
that	O
instruction	O
.	O
</s>
<s>
This	O
compensates	O
for	O
the	O
architecture	O
's	O
lack	O
of	O
index	B-General_Concept
registers	I-General_Concept
.	O
</s>
<s>
The	O
GE-600/Honeywell	O
6000	O
series	O
(	O
1964	O
)	O
supports	O
a	O
single-instruction	O
repeat	O
(	O
)	O
,	O
a	O
double-instruction	O
repeat	O
(	O
)	O
,	O
and	O
a	O
linked-list	B-Data_Structure
repeat	O
(	O
)	O
.	O
</s>
<s>
The	O
x86	B-Operating_System
ISA	O
,	O
starting	O
with	O
the	O
8086	B-General_Concept
,	O
includes	O
a	O
series	O
of	O
special-purpose	O
repeat	B-General_Concept
instructions	I-General_Concept
(	O
)	O
which	O
are	O
called	O
"	O
repeat	O
string	O
operation	O
prefixes	O
"	O
and	O
may	O
only	O
be	O
applied	O
to	O
a	O
small	O
number	O
of	O
string	O
instructions	O
(	O
)	O
.	O
</s>
<s>
The	O
Texas	B-Architecture
Instruments	I-Architecture
TMS320	I-Architecture
digital	O
signal	O
processor	O
(	O
1983	O
)	O
includes	O
an	O
instruction	O
for	O
repeating	O
a	O
single-cycle	O
instruction	O
or	O
two	O
single-cycle	O
instruction	O
in	O
parallel	O
(	O
)	O
and	O
an	O
instruction	O
for	O
repeating	O
a	O
block	O
of	O
instructions	O
(	O
)	O
.	O
</s>
<s>
The	O
instruction	O
or	O
instruction	O
pair	O
to	O
be	O
executed	O
follows	O
the	O
repeat	B-General_Concept
instruction	I-General_Concept
.	O
</s>
<s>
In	O
the	O
case	O
of	O
the	O
TMS320	B-Architecture
,	O
a	O
block	O
of	O
up	O
to	O
64Kbytes	O
can	O
be	O
repeated	O
.	O
</s>
