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
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To: djgpp AT delorie DOT com
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"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.