joncampbell123/dosbox-x dosbox-x-windows-6ba2abd942920bc343f48dfb6f874971e15c20c4.zip

dosbox-x-windows-6ba2abd942920bc343f48dfb6f874971e15c20c4

on GitHub

286 BIOS reset vector added. Some reset modes supported now. Added support to emulate double fault and triple fault exceptions. Doing so allows 286-based code to switch in and out of protected mode as needed. Added 8086, 80186, and 286 cpu types to normal core. The 286 core is mostly tested, while the 8086 and 80186 cores are experimental. It is now possible to run Windows 3.0 and 3.1 in standard mode with cputype=286, where if Windows detects a 286 it uses the BIOS reset vector and causes a triple fault as a method of returning back to real mode. Added code to FPU emulation where if cputype=286 it changes FCOMP emulation to act like a 287 (makes -inf == +inf which is the common test to determine 80287 vs 80387). Added code to zero INT 67h if ems=false, this was added for a DOS demo that refused to run because it thought EMM386.EXE was resident despite the fact that ems=false, it turned out the demo only checked to see if INT 67h was nonzero rather than properly checking for expanded memory services. Added code to setup the "default interrupt callback" in the DOS kernel such that INT 1 and INT 3 debug interrupts now point directly at the IRET instruction, which was added for another DOS demo that refused to run because it thought DOSBox's callback instruction was a debugger. More comments, and lots of other minor fixes.