Re: [Tinycc-devel] TinyCC for bootstrapping (with patches)

[Christian Jullien]

It looks true for float and double, see also long double which differs greatly


On Windows: 32 and 64 bit with cl
sizeof(float)       4
sizeof(double)      8
sizeof(long double) 8

On Linux ARM32 (Rpi)
sizeof(float)       4
sizeof(double)      8
sizeof(long double) 8

On Linux ARM64
sizeof(float)       4
sizeof(double)      8
sizeof(long double) 16

On Linux x64
address@hidden ~]$ gcc -m32 foo.c -o foo && ./foo
sizeof(float)       4
sizeof(double)      8
sizeof(long double) 12

address@hidden ~]$ gcc -m64 foo.c -o foo && ./foo
sizeof(float)       4
sizeof(double)      8
sizeof(long double) 16

-----Original Message-----
From: Tinycc-devel [mailto:address@hidden On Behalf Of Giovanni Mascellani
Sent: lundi 14 janvier 2019 11:09
To: address@hidden
Subject: Re: [Tinycc-devel] TinyCC for bootstrapping (with patches)

Hi,

Il 13/01/19 19:37, Daniel Glöckner ha scritto:
> I really like the idea of using a library to perform floating point 
> operations and I also like that you made it optional.

Good!

> But it looks like you made the assumption that long double is an
> 80 bit floating point type. This is only true for x86-32. You have to 
> look at the LDOUBLE_SIZE macro to determine which of float64_t, 
> extFloat80_t, and float128_t to use (For x86-32 it is 12 instead of
> 10 because of padding).

I agree. As I said in my first email, for the moment the patch is 
Intel-specific (and actually i386-specific). I was asking for preliminary 
opinions, because if people immediately think that such a patch would never be 
accepted, then I would not bother generalizing it.

BTW, it is correct to assume that for all architecture supported by tcc float 
and double are always 32 and 64 bits?

Thanks, Giovanni.
--
Giovanni Mascellani <address@hidden> Postdoc researcher - Université Libre de 
Bruxelles