Can all published DOS interrupts be emulated with protected-mode code?
While a protected-mode system could be coded this way, we don’t do this in our DOS extenders. Rather almost all DOS and BIOS interrupts are resignaled in real mode, after switching from protected mode. Of course, there is some copying of data and translation of pointers to make it work transparently, but we chose to code our systems to work this way to maximize compatibility. By reflecting most interrupts to real mode, we insure that your DOS-extended program will be maximally compatible with existing software and systems. For example, if a TSR hooks the disk reading interrupt, because we reflect the disk reading interrupts to real mode, we insure that the TSR hook will be called. The downside to this approach is that every DOS and BIOS call causes a switch to real mode and back again. Although most computers can perform such switching at a rate of tens of thousands of switches per second, the switching time can have a noticible impact on the performance of programs which heavily use D
Related Questions
- When moving salary from a non-sponsored fund source to a sponsored fund source and a Salary Reduction (SRB DOS code) was accessed, does the Salary Reduction DOS code (SRB) get moved also?
- Can all published DOS interrupts be emulated with protected-mode code?
- So, what DOS interrupts are handled by protected-mode code?
