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From: ForthNet@willett.pgh.pa.us (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: Forth vs C
Message-ID: <2046.UUL1.3#5129@willett.pgh.pa.us>
Date: 4 Dec 90 03:37:18 GMT
Organization: String, Scotch tape, and Paperclips.  (in Pgh, PA)
Lines: 20

Category 2,  Topic 14
Message 5         Mon Dec 03, 1990
NMORGENSTERN                 at 19:43 EST
 
    The Forth word DriveError? in a previous upload is incorrect. DOS has some
VERY STRANGE effects. I was unaware that Int 37, leaves the flags on the stack
when it returns, and you have to remove them before you return!

DriveError? will test for such problems as door open, etc. by calling INT 25H
which is absolute disk read. It attempts to read 1 sector into PAD, and
returns an error flag. Drive is 0 for A: 1 for B: etc., which is DOS standard.
Return is 0 if ok. 2 is drive not ready. See DOS manual for other codes.

code DriveError? ( drive -- f) pop ax  xor ah, ah  mov cx, # 1  xor dx, dx mov
bx, # pad  int 37  bx pop    \ This line added to previous upload xor ah, ah 
1push end-code.

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