XT implies 8086 and there are more real address mode instructions than those available in 8086. AFAIK real address mode can use pretty much any 32bit instructions with a prefix, which is what this project is doing.
(this incompatibility bit me a bit many years ago when i was writing a small real mode OS in assembly - i used a bunch of instructions i thought were available in 8086 but when i tried the OS on a real XT machine it would lock up :-P)
(this incompatibility bit me a bit many years ago when i was writing a small real mode OS in assembly - i used a bunch of instructions i thought were available in 8086 but when i tried the OS on a real XT machine it would lock up :-P)