Bitwise and

[Joachim]

I have the following definition in one class

public const Int32 C_RET_ERR_INVALID_BAND = unchecked((int)
0x80080000);

which I am accessing from another class:

string RetValAsString(
Int32 return_value)
{
int l_r = Common.C_RET_ERR_INVALID_BAND;
int l_res = (return_value & l_r);
if (l_res != 0)

When return_value = -7 (0x80000007) I think that I should get l_res == 0, i e

1000 0000 0000 1000 0000 0000 0000 0000
1000 0000 0000 0000 0000 0000 0000 0111
-------------------------------------------------
1000 0000 0000 0000 0000 0000 0000 0000

but I instead get 0x80080000, i e

1000 0000 0000 1000 0000 0000 0000 0000

Where am I doing / thinking wrong?

[Michael C]

"Joachim" <Jo*****@discussions.microsoft.comwrote in message
news:1A**********************************@microsof t.com...

>I have the following definition in one class

public const Int32 C_RET_ERR_INVALID_BAND = unchecked((int)
0x80080000);

which I am accessing from another class:

string RetValAsString(
Int32 return_value)
{
int l_r = Common.C_RET_ERR_INVALID_BAND;
int l_res = (return_value & l_r);
if (l_res != 0)

When return_value = -7 (0x80000007) I think that I should get l_res == 0,
i e

For 0x80080000 & 0x80000007 you should get 0x80000000 not 0. Aside from that
are you sure the values in the vars are correct?

Michael

[Michael C]

"Joachim" <Jo*****@discussions.microsoft.comwrote in message
news:1A**********************************@microsof t.com...

When return_value = -7 (0x80000007) I think that I should get l_res == 0,
i e

I missed the problem before. -7 is not 0x80000007, it's 0xFFFFFFF9.

Michael

[Joachim]

Thanks Michael,

but isn't 0x80000000 for an Int32 equal to 0?
The values are those which come up when I debug.

Regards,
Joachim

"Michael C" wrote:

"Joachim" <Jo*****@discussions.microsoft.comwrote in message
news:1A**********************************@microsof t.com...

I have the following definition in one class

public const Int32 C_RET_ERR_INVALID_BAND = unchecked((int)
0x80080000);

which I am accessing from another class:

string RetValAsString(
Int32 return_value)
{
int l_r = Common.C_RET_ERR_INVALID_BAND;
int l_res = (return_value & l_r);
if (l_res != 0)

When return_value = -7 (0x80000007) I think that I should get l_res == 0,
i e

For 0x80080000 & 0x80000007 you should get 0x80000000 not 0. Aside from that
are you sure the values in the vars are correct?

Michael

[Joachim]

Ok... Thanks!

"Michael C" wrote:

"Joachim" <Jo*****@discussions.microsoft.comwrote in message
news:1A**********************************@microsof t.com...

When return_value = -7 (0x80000007) I think that I should get l_res == 0,
i e

I missed the problem before. -7 is not 0x80000007, it's 0xFFFFFFF9.

Michael

[Michael C]

"Joachim" <Jo*****@discussions.microsoft.comwrote in message
news:AA**********************************@microsof t.com...

Thanks Michael,

but isn't 0x80000000 for an Int32 equal to 0?
The values are those which come up when I debug.

No, 0x00000000 is 0. 0x80000000 is -2^31.
-1 is 0xFFFFFFFF
-2 is 0xFFFFFFFE
so 0x80000000 is the largest negative value.

Michael