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#x87

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FreeDOSDeep Dive October 3, 2026 7 min read

x87 Exception Reporting in DOS: Masks, Sticky Flags, and Deferred Faults

Diagnose x87 arithmetic faults using status and control words, sticky exception flags, synchronization points, and CPU-specific DOS handling.

#freedos#dos#x87

FreeDOSDeep Dive October 3, 2026 7 min read

Preserving x87 State Across DOS Libraries and Interrupt Boundaries

Understand what x87 environment and full-state saves actually preserve, when save instructions reset the unit, and how DOS code avoids corrupting callers.

#freedos#x87#assembly