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routines (V86 requests from the client and hardware interrupt handlers): - Install trampoline real mode interrupt handlers at IDT vectors 0x20-0x2f to handle hardware interrupts by invoking the appropriate vector (0x8-0xf or 0x70-0x78). This allows the 8259As to use vectors 0x20-0x2f in real mode as well as protected mode will ensuring that the master 8259A doesn't share IDT space with CPU exceptions in protected mode. - Since we don't need to reserve space for page tables and a page directory anymore since dropping paging support, move the TSS and protected mode IDT up by 16k. Grow the ring 1 link stack by 16k as a result. - Repurpose the ring 1 link stack to be used as a real mode stack when invoking real mode routines either via a V86 request or a hardware interrupts. This simplifies a few things as we avoid disturbing the original user stack. - Add some more block comments to explain how the code interacts with the V86 structure as this wasn't immediately obvious from the prior comments (e.g. that we explicitly copy the seg regs for real mode out of the V86 struct onto the stack to be popped off when going into real mode, etc.). Also, document some of the stack frames we create going to real mode and back. - Remove all of the virtual 86 related code including having to simulate various instructions and BIOS calls on a trap from virtual 86 mode. - Explicitly panic if a user client attempts to perform a V86 CALL request that isn't a far call. - Bump version to 1.2. Assuming this works ok this should fix some of the long standing issues with USB booting as well as etherboot. MFC after: 2 weeks Submitted by: kib (some parts from his original real mode patch) |
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| btx | ||
| btxldr | ||
| lib | ||
| Makefile | ||
| Makefile.inc | ||