From:	Nick <jp_prongs AT yahoo DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: bit and bytes ... help [ biosdisk ]
Date:	Tue, 11 Jun 2002 18:29:53 -0400
Organization:	MindSpring Enterprises
Lines:	21
Message-ID:	<3D0679E1.E9F97F93@yahoo.com>
References:	<eGkN8.90451$6v2 DOT 3674113 AT twister DOT southeast DOT rr DOT com>
NNTP-Posting-Host:	a5.f7.88.b7
Mime-Version:	1.0
X-Server-Date:	11 Jun 2002 22:30:12 GMT
X-Mailer:	Mozilla 4.75 [en] (Win98; U)
X-Accept-Language:	en
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

"Frank Troy Cook Jr." wrote:
> 
> i need to extract drive information returned from a biosdisk call. for
> example:
-snip-
> i understandfrom the djgpp site that the first 4 bytes return:
> byte 0 = sectors per track (bits 0..5) and top two bits of cylinder (in bits
> 6..7)
> byte 1 = cyliders (bits 0..7)
> byte 2 = number of drives
> byte 3 = number of heads
> how do i convert this to integer numbers correctly?

int sectors_per_track = buffer[0] & 0x1f;
int cylinders = buffer[1] + ((buffer[0] & 0xc0) << 2);
int number_of_drives = buffer[2];
int number_of_heads = buffer[3];

Some of the parentheses on "cylinders" may be unnecessary, but I think it's clearer that way.

- Raw text -