RE: [Dev-C++] new is a wrapper around malloc so...

[Daniel G. <sp...@ho...>]

All I know is that the MSDN documentation I read says 2GB. I'm not sure 
about how you calculate it all, so you're one up on me!


>From: "Abhijit Shylanath" <mu...@gm...>
>To: "Daniel Glenfield" <sp...@ho...>
>CC: "Dev-Cpp mailing list" <dev...@li...>
>Subject: RE: [Dev-C++] new is a wrapper around malloc so...
>Date: Wed, 16 Jul 2003 00:40:19 +0530
>
>
> > In 16 bit your code is separated into 'segments' each a maximum of 64k 
>in
> > size. 32-bit can have up to 2GB segments (!!!).
>
>4G, right? (2^32).
>
>However, that's true only on a 32-bit system (as you've said)... what
>platform are you building on? On 16-bit (`real-mode') DOS, even though
>sizeof(farptr) will give you four, it cannot address 32-bits worth of
>memory. Far pointers work like this:
>
>	32 bits of farptr  =
>	16 bits of segment .
>	16 bits of offset
>
>The effective address is actually calculated by multiplying the segment by
>16 decimal (0x10 (which is equivalent to left-shifting by four)) and then
>ADDING the offset... so that if your far-ptr has this value:
>
>	0x1234abcd
>
>Written as:
>
>	1234:abcd
>
>Its effective address, which is worth 20-bits (and can therefore address
>2^20 = 1M) is calculated  as:
>
>	0x12340
>+	 0xabcd
>-------------
>=	0x1cf0d
>
>Whereas, in the flat memory model(protected-mode), the effective address
>would itself be
>
>	0x1234abcd
>
>--
>Abhijit Shylanath
>Homepage: http://mudeth.tripod.com/
>

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