12.3.3 Interrupt-Time Code

A 32-bit code segment in a Windows application must not contain code that is executed at interrupt time. Also, it must not contain data that is accessed at interrupt time. Any code executed at interrupt time must be in a USE16 code segment. The code must use a USE16 stack. Data used at interrupt time must be USE16 data. This rule also applies to processor exceptions (such as the coprocessor exception) because they are handled as interrupts are handled. Note, however, that it is acceptable for a 32-bit code segment to access data in a USE16 data segment.