| 2345678910111213141516171819202122232425262728293031323334 |
转自：https://github.com/darrenhp/Practise/blob/master/csapp/ch02/2_73.c
加法处理，正溢出输出TMax,负溢出输出Tmin.
#include<stdio.h>
#include<limits.h>
int
saturating_add
(
int
x
,
int
y
)
{
int
mask
=
INT_MIN
;
int
sum
=
x
+
y
;
int
w
=
(
sizeof
(
int
)
<<
3
)
-
1
;
int
tmin
=
(
((
x
&
mask
)
&&
(
y
&
mask
)
&&!
(
sum
&
mask
))
<<
w
>>
w
)
&
INT_MIN
;
int
tmax
=
(
((
~
x
&
mask
)
&&
(
~
y
&
mask
)
&&
(
sum
&
mask
))
<<
w
>>
w
)
&
INT_MAX
;
return
(
sum
&
~
(
!
(
tmin
|
tmax
)))
|
tmin
|
tmax
;
}
void
show_saturating_add
(
int
x
,
int
y
)
{
printf
(
"saturating_add(0x%08X, 0x%08X) = 0x%08X:%d
\n
"
,
x
,
y
,
saturating_add
(
x
,
y
),
saturating_add
(
x
,
y
)
);
printf
(
"%d + %d = %d
\n
"
,
x
,
y
,
x
+
y
);
printf
(
"
\n
"
);
}
int
main
()
{
show_saturating_add
(
0xFFFFFFFF
,
0x80000000
);
show_saturating_add
(
0xFFFFFFFF
,
0xFFFFFFFF
);
show_saturating_add
(
0x7FFFFFF0
,
0x0000000F
);
show_saturating_add
(
0x7FFFFFF5
,
0x0000000F
);
show_saturating_add
(
0x55555555
,
0x55555555
);
show_saturating_add
(
0x55555555
,
0x33333333
);
show_saturating_add
(
0x55555555
,
0x23333333
);
show_saturating_add
(
0x55555555
,
0x2FFFFFFF
);
}
|