I don't know offhand what instructions were introduced in Pentium or later.
Doing some googling... 486 had cmpxchg, that's good.
Seems it didn't have rdtsc. It's not out of the question, I might say even pretty common, for user mode code to use that one via inline asm to implement a timer.
Obviously no SIMD instructions. If they say they're supporting 686 or better they might have some compiler flags that depend on mmx or similar? SSE came late to P6.
Doing some googling... 486 had cmpxchg, that's good.
Seems it didn't have rdtsc. It's not out of the question, I might say even pretty common, for user mode code to use that one via inline asm to implement a timer.
Obviously no SIMD instructions. If they say they're supporting 686 or better they might have some compiler flags that depend on mmx or similar? SSE came late to P6.