<s>
An	O
indirect	B-Language
branch	I-Language
(	O
also	O
known	O
as	O
a	O
computed	B-Language
jump	I-Language
,	O
indirect	B-Language
jump	I-Language
and	O
register-indirect	B-Language
jump	I-Language
)	O
is	O
a	O
type	O
of	O
program	O
control	O
instruction	O
present	O
in	O
some	O
machine	B-Language
language	I-Language
instruction	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
Rather	O
than	O
specifying	O
the	O
address	B-General_Concept
of	O
the	O
next	O
instruction	O
to	O
execute	B-General_Concept
,	O
as	O
in	O
a	O
direct	O
branch	B-General_Concept
,	O
the	O
argument	O
specifies	O
where	O
the	O
address	B-General_Concept
is	O
located	O
.	O
</s>
<s>
An	O
example	O
is	O
'	O
jump	O
indirect	O
on	O
the	O
r1	O
register	B-General_Concept
 '	O
,	O
which	O
means	O
that	O
the	O
next	O
instruction	O
to	O
be	O
executed	O
is	O
at	O
the	O
address	B-General_Concept
in	O
register	B-General_Concept
r1	O
.	O
</s>
<s>
The	O
address	B-General_Concept
to	O
be	O
jumped	O
to	O
is	O
not	O
known	O
until	O
the	O
instruction	O
is	O
executed	O
.	O
</s>
<s>
Indirect	B-Language
branches	I-Language
can	O
also	O
depend	O
on	O
the	O
value	O
of	O
a	O
memory	B-General_Concept
location	I-General_Concept
.	O
</s>
<s>
An	O
indirect	B-Language
branch	I-Language
can	O
be	O
useful	O
to	O
make	O
a	O
conditional	B-General_Concept
branch	I-General_Concept
,	O
especially	O
a	O
multiway	O
branch	B-General_Concept
.	O
</s>
<s>
For	O
instance	O
,	O
based	O
on	O
program	O
input	O
,	O
a	O
value	O
could	O
be	O
looked	O
up	O
in	O
a	O
jump	O
table	O
of	O
pointers	O
to	O
code	B-Language
for	O
handling	O
the	O
various	O
cases	O
implied	O
by	O
the	O
data	O
value	O
.	O
</s>
<s>
The	O
data	O
value	O
could	O
be	O
added	O
to	O
the	O
address	B-General_Concept
of	O
the	O
table	O
,	O
with	O
the	O
result	O
stored	O
in	O
a	O
register	B-General_Concept
.	O
</s>
<s>
An	O
indirect	B-Language
jump	I-Language
could	O
then	O
be	O
made	O
based	O
on	O
the	O
value	O
of	O
that	O
register	B-General_Concept
,	O
efficiently	O
dispatching	O
program	O
control	O
to	O
the	O
code	B-Language
appropriate	O
to	O
the	O
input	O
.	O
</s>
<s>
In	O
a	O
similar	O
manner	O
,	O
subroutine	O
call	O
instructions	O
can	O
be	O
indirect	O
,	O
with	O
the	O
address	B-General_Concept
of	O
the	O
subroutine	O
to	O
be	O
called	O
specified	O
in	O
memory	O
.	O
</s>
<s>
Function	B-Language
Pointers	I-Language
are	O
typically	O
implemented	O
with	O
indirect	O
subroutine	O
calls	O
.	O
</s>
<s>
Indirect	B-Language
branches	I-Language
were	O
one	O
of	O
the	O
attack	O
surfaces	O
of	O
Spectre	B-Error_Name
.	O
</s>
<s>
To	O
mitigate	O
the	O
attack	O
GCC	O
8.1	O
introduced	O
the	O
following	O
new	O
options	O
:	O
-mindirect-branch	O
=	O
,	O
-mfunction-return	O
=	O
and	O
-mindirect-branch-register	O
.	O
</s>
<s>
|	O
RISC-V	B-Device
:	O
</s>
