78 lines
2.0 KiB
HTML
78 lines
2.0 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type"
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content="text-html; charset=Windows-1252">
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<title>INT 21,52 - Get Pointer to DOS "INVARS"
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(Undocumented)</title>
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<meta name="FORMATTER" content="Microsoft FrontPage 2.0">
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</head>
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<body>
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<h1><a name="kap_interrupt_2410"></a>INT 21,52 - Get Pointer to
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DOS "INVARS" (Undocumented)</h1>
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<p> AH = 52h</p>
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<p> on return:</p>
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<p> ES:BX = pointer to DOS "invars", a table of
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pointers used by DOS.</p>
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<p> Known "invars" fields follow (varies with DOS
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version):</p>
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<p> % Offset Size Description</p>
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<p> -12 word sharing retry count (DOS 3.1-3.3)</p>
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<p> -10 word sharing retry delay (DOS 3.1-3.3)</p>
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<p> -8 dword pointer to current disk buffer (DOS 3.x)</p>
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<p> -4 word pointer in DOS code segment of unread CON input;</p>
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<p> 0 indicates no unread input (DOS 3.x)</p>
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<p> -2 word segment of first Memory Control Block (~MCB~)</p>
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<p> 00 dword pointer to first ~DRIVE PARAMETER TABLE~ (A:) in
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chain</p>
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<p> 04 dword pointer to DOS ~System File Table~ (SFT)</p>
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<p> 08 dword pointer to $CLOCK device driver</p>
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<p> 0C dword pointer to CON device driver</p>
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<p> 10 byte number of logical drives in system</p>
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<p> 11 word maximum bytes/block of any block device</p>
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<p> 13 dword pointer to DOS cache buffer header</p>
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<p> 17 18bytes NUL device header, first 4 bytes of device header</p>
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<p> point to the next device in device chain</p>
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<hr>
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<table border="0" width="100%" cols="3">
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<tr>
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<td width="33%">Zurück zum <a href="inte1at0.htm">Interrupt
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Info</a>. </td>
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<td align="center" width="33%"><a
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href="mailto:Roger.Morgan@htl-steyr.ac.at">Roger Morgan</a>
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/ 1998 </td>
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<td align="right" width="33%"><font size="1">L.Änderung <!--webbot
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bot="Timestamp" s-type="EDITED" s-format="%d.%m.%y"
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startspan -->29.03.99<!--webbot bot="Timestamp" endspan
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i-checksum="13964" --> </font></td>
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</tr>
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</table>
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</body>
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</html>
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