29 lines
1.1 KiB
HTML
29 lines
1.1 KiB
HTML
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Ordinarily, a handler installed with <a href="api/310205.html">DPMI
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Function 0205H</a> will only service software interrupts that are
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executed in protected mode; real mode software interrupts are passed
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to handlers installed with DOS Int 21H Function 25H issued from real
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mode, <a href="api/310201.html">DPMI Int 31H Function 0201H</a>, or by
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direct manipulation of the interrupt vector table at real mode address
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0000:0000. However, there are three real mode software interrupts
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that a DPMI host will always reflect to a protected mode handler, if
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one is installed:
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<ul>
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Int 1CH - ROM BIOS timer tick interrupt<br>
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Int 23H - DOS Ctrl+C interrupt<br>
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Int 24H - DOS critical error interrupt<br>
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</ul>
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Clients should never terminate during the processing of interrupts
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that were reflected from real mode. Such a termination might prevent
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the DPMI host from cleaning up the client's resources properly. <p>
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Protected mode handlers for software interrupts 0-7 are called with
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virtual interrupts disabled and trace flag reset, and these handlers
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should return with interrupts enabled. All other software interrupts
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do not modify the interrupt flag state. <p>
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