Re: [GD-General] ieee754 -0.0f?

[Andras B. <and...@gm...>]

I run this code:

float f = -0.0f;
void* p = *(reinterpret_cast<void**>(&f));
::printf("%f = %p\n", f, p);

And it prints all zeroes. For any other number I see the correct  
hexadecimal representation of the float number.


Thanks,

Andras



On Wed, 01 Feb 2006 10:32:28 -0700, Peter <pe...@to...> wrote:

> what is the context here?  If you're interpreting 0x80000000 (32 bit  
> int) as a 32-bit IEEE float it's -0.0f   and 0x00000000 is 0.0f.
>   Where are you seeing the -0.0f? In a debugger? I think you must be  
> seeing some idiosyncrasy of your development environment or toolchain.
>
> Andras Balogh wrote:
>
>> I know that -0.0f == +0.0f is true, but the floating point  
>> representation  of the two numbers should be different, no? Shouldn't  
>> the negative zero  have the sign bit set? Well, on my machine -0.0 and  
>> 0.0 are bitwise  equal!! What's going on here?
>>
>> thx,
>>
>>
>> Andras