Since a certain someone managed to run ddcpuid on Windows NT 3.51 with, I believe, an original Pentium (thankfully baseline for dmd on i386 targets Pentium Pro) only has up to CPUID.01h, the program assumes CPUID.04h and crashes with a division by 0 error.
If CPUID.04h cannot be reached at the make to make out the topology, it's safe to assume 1 core 1 thread.
Since a certain someone managed to run ddcpuid on Windows NT 3.51 with, I believe, an original Pentium (thankfully baseline for dmd on i386 targets Pentium Pro) only has up to CPUID.01h, the program assumes CPUID.04h and crashes with a division by 0 error.
If CPUID.04h cannot be reached at the make to make out the topology, it's safe to assume 1 core 1 thread.