<s>
numeric_std	O
is	O
a	O
library	O
package	O
defined	O
for	O
VHDL	B-Language
.	O
</s>
<s>
It	O
provides	O
arithmetic	B-Algorithm
functions	I-Algorithm
for	O
vectors	O
.	O
</s>
<s>
Overrides	O
of	O
std_logic_vector	O
are	O
defined	O
for	O
signed	B-Algorithm
and	I-Algorithm
unsigned	I-Algorithm
arithmetic	O
.	O
</s>
<s>
It	O
defines	O
numeric	O
types	O
and	O
arithmetic	B-Algorithm
functions	I-Algorithm
for	O
use	O
with	O
synthesis	O
tools	O
.	O
</s>
<s>
Two	O
numeric	O
types	O
are	O
defined	O
:	O
UNSIGNED	B-Algorithm
(	O
represents	O
UNSIGNED	B-Algorithm
number	I-Algorithm
in	O
vector	O
form	O
)	O
and	O
SIGNED	O
(	O
represents	O
a	O
SIGNED	O
number	O
in	O
vector	O
form	O
)	O
.	O
</s>
<s>
This	O
package	O
contains	O
overloaded	O
arithmetic	O
operators	O
on	O
the	O
SIGNED	B-Algorithm
and	I-Algorithm
UNSIGNED	I-Algorithm
types	O
.	O
</s>
<s>
This	O
package	O
does	O
not	O
provide	O
overrides	O
for	O
mixing	O
signed	B-Algorithm
and	I-Algorithm
unsigned	I-Algorithm
functions	O
.	O
</s>
<s>
For	O
an	O
unsigned	B-Algorithm
vector	O
,	O
a	O
size	O
increase	O
fills	O
the	O
leftmost	O
bits	O
with	O
zero	O
,	O
while	O
truncation	O
retains	O
n	O
rightmost	O
bits	O
.	O
</s>
