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Message-ID: | <4166DE17.82290D05@yahoo.com> |
From: | CBFalconer <cbfalconer AT yahoo DOT com> |
Organization: | Ched Research |
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Newsgroups: | comp.os.msdos.djgpp |
Subject: | Re: Free() crash my program! |
References: | <D7Kdnfji89etsfvcRVn-qA AT comcast DOT com> <41663c2c$0$179$cc7c7865 AT news DOT luth DOT se> <4166513D DOT 92D782BF AT yahoo DOT com> <01c4ad2e$Blat.v2.2.2$6d165ee0 AT zahav DOT net DOT il> |
Lines: | 28 |
Date: | Fri, 08 Oct 2004 18:53:34 GMT |
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X-Trace: | bgtnsc04-news.ops.worldnet.att.net 1097261614 12.76.142.242 (Fri, 08 Oct 2004 18:53:34 GMT) |
NNTP-Posting-Date: | Fri, 08 Oct 2004 18:53:34 GMT |
To: | djgpp AT delorie DOT com |
DJ-Gateway: | from newsgroup comp.os.msdos.djgpp |
Reply-To: | djgpp AT delorie DOT com |
Eli Zaretskii wrote: > > > From: CBFalconer <cbfalconer AT yahoo DOT com> > > Date: Fri, 08 Oct 2004 08:57:58 GMT > > > > Shouldn't there be some limit on the len parameter? Just > > considering the nature of the DOS memory addressing, I would expect > > it to not work for anything over 65535. > > dosmemget is a DJGPP function, it doesn't call any DOS interrupts, and > so isn't limited by DOS limitations. > > What dosmemget does is simply copy a block of memory from here to > there, and it uses the fact that the conventional memory is mapped > into a special segment of the DJGPP address space whose selector is > _dos_ds and whose limit is 1MB + 64KB. The code that copies the > memory block runs in protected mode, using 32-bit registers for > segment offsets. Thus, there's no 64KB limit. If you want, you can > copy the entire DOS address space in one go. i.e. len cannot be greater than 1M + 64KB - addr, no? -- Chuck F (cbfalconer AT yahoo DOT com) (cbfalconer AT worldnet DOT att DOT net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net> USE worldnet address!
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