<s>
BLISS	B-Language
is	O
a	O
system	B-Language
programming	I-Language
language	I-Language
developed	O
at	O
Carnegie	O
Mellon	O
University	O
(	O
CMU	O
)	O
by	O
W	O
.	O
A	O
.	O
Wulf	O
,	O
D	O
.	O
B	O
.	O
Russell	O
,	O
and	O
A	O
.	O
N	O
.	O
Habermann	O
around	O
1970	O
.	O
</s>
<s>
It	O
was	O
perhaps	O
the	O
best	O
known	O
system	O
language	O
until	O
C	B-Language
debuted	O
a	O
few	O
years	O
later	O
.	O
</s>
<s>
Since	O
then	O
,	O
C	B-Language
became	O
popular	O
and	O
common	O
,	O
and	O
BLISS	B-Language
faded	O
into	O
obscurity	O
.	O
</s>
<s>
When	O
C	B-Language
was	O
in	O
its	O
infancy	O
,	O
a	O
few	O
projects	O
within	O
Bell	O
Labs	O
debated	O
the	O
merits	O
of	O
BLISS	B-Language
vs.	O
C	B-Language
.	O
</s>
<s>
BLISS	B-Language
is	O
a	O
typeless	O
block-structured	O
programming	O
language	O
based	O
on	O
expressions	O
rather	O
than	O
statements	O
,	O
and	O
includes	O
constructs	O
for	O
exception	B-General_Concept
handling	I-General_Concept
,	O
coroutines	B-Architecture
,	O
and	O
macros	O
.	O
</s>
<s>
It	O
does	O
not	O
include	O
a	O
goto	B-Application
statement	O
.	O
</s>
<s>
The	O
original	O
Carnegie	O
Mellon	O
compiler	B-Language
was	O
notable	O
for	O
its	O
extensive	O
use	O
of	O
optimizations	B-Application
,	O
and	O
formed	O
the	O
basis	O
of	O
the	O
classic	O
book	O
The	O
Design	O
of	O
an	O
Optimizing	B-Application
Compiler	I-Application
.	O
</s>
<s>
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
developed	O
and	O
maintained	O
BLISS	B-Language
compilers	B-Language
for	O
the	O
PDP-10	B-Device
,	O
PDP-11	B-Device
,	O
VAX	B-Device
,	O
DEC	B-Architecture
PRISM	I-Architecture
,	O
MIPS	B-Device
,	O
DEC	B-Device
Alpha	I-Device
,	O
and	O
Intel	B-Device
IA-32	I-Device
,	O
The	O
language	O
did	O
not	O
become	O
popular	O
among	O
customers	O
and	O
few	O
had	O
the	O
compiler	B-Language
,	O
but	O
DEC	O
used	O
it	O
heavily	O
in-house	O
into	O
the	O
1980s	O
;	O
most	O
of	O
the	O
utility	O
programs	O
for	O
the	O
OpenVMS	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
were	O
written	O
in	O
BLISS-32	O
.	O
</s>
<s>
The	O
DEC	O
BLISS	B-Language
compiler	B-Language
has	O
been	O
ported	O
to	O
the	O
IA-64	B-General_Concept
and	O
x86-64	B-Device
architectures	O
as	O
part	O
of	O
the	O
ports	O
of	O
OpenVMS	B-Operating_System
to	O
these	O
platforms	O
.	O
</s>
<s>
The	O
x86-64	B-Device
BLISS	B-Language
compiler	B-Language
uses	O
LLVM	B-Application
as	O
its	O
backend	O
code	B-Application
generator	I-Application
,	O
replacing	O
the	O
proprietary	O
GEM	O
backend	O
used	O
for	O
Alpha	B-Device
and	O
IA-64	B-General_Concept
.	O
</s>
<s>
The	O
BLISS	B-Language
language	I-Language
has	O
the	O
following	O
characteristics	O
:	O
</s>
<s>
on	O
a	O
16-bit	O
machine	O
such	O
as	O
the	O
PDP-11	B-Device
,	O
a	O
constant	O
is	O
16	O
bits	O
;	O
on	O
a	O
VAX	B-Device
computer	O
,	O
constants	O
are	O
32	O
bits	O
,	O
and	O
on	O
a	O
PDP-10	B-Device
,	O
a	O
constant	O
is	O
36	O
bits	O
.	O
</s>
<s>
Block	O
statements	O
are	O
similar	O
to	O
those	O
of	O
ALGOL	B-Language
:	O
a	O
block	O
is	O
started	O
with	O
a	O
BEGIN	O
statement	O
and	O
terminated	O
with	O
END	O
.	O
</s>
<s>
As	O
with	O
ALGOL	B-Language
,	O
statements	O
are	O
terminated	O
with	O
the	O
semicolon	O
(";	O
"	O
)	O
.	O
</s>
<s>
Declaring	O
a	O
variable	O
normally	O
causes	O
the	O
compiler	B-Language
to	O
allocate	O
space	O
for	O
it	O
;	O
when	O
necessary	O
,	O
a	O
variable	O
may	O
be	O
assigned	O
a	O
fixed	O
machine	O
address	O
via	O
the	O
BIND	O
declaration	O
.	O
</s>
<s>
The	O
language	O
supports	O
arrays	B-Data_Structure
,	O
which	O
are	O
referred	O
to	O
as	O
structures	O
,	O
and	O
declared	O
with	O
the	O
keyword	O
VECTOR	O
.	O
</s>
<s>
The	O
language	O
supports	O
some	O
high-level	B-Language
programming	I-Language
language	I-Language
constructs	O
such	O
as	O
:	O
</s>
<s>
The	O
following	O
example	O
is	O
taken	O
verbatim	O
from	O
the	O
Bliss	B-Language
Language	I-Language
Manual	O
:	O
</s>
