Note: the Mode Flag is supported only on the NEC V20/30,

   it is reserved on Intel CPUs.

   The diagram below shows the names for each bit as referenced to in most
   books, along with the CPU in which the bit was =officially= introduced.

      Description:                  Name:   CPU introduced:

      CPUID available───────────────ID      Pentium
      Virtual Interrupt Pending─────VIP     Pentium
      Virtual Interrupt flag────────VI      Pentium
      Alignment Check Flag──────────AC      486
      Virtual-86 Mode Flag──────────VM      386
      Resume Flag───────────────────RF      386
      Mode Flag (8O8O emulation on)─MD      V20/V30 only
      Nested Task───────────────────NT      286
      I/O privilege level 0..3──────IOPL    286
      Overflow Flag─────────────────OF       86
      Direction Flag (1=up)─────────DF       86
      Interrupt Flag (1=enabled)────IF       86
      Trap Flag (single step mode)──TF       86
      Sign Flag─────────────────────SF       86
      Zero Flag─────────────────────ZF       86
      Auxiliary carry Flag──────────AF       86
      Parity Flag───────────────────PF       86
      Carry Flag────────────────────CF       86

(8080 is written here as 8O8O to avoid visual confusion with the 8088).
(Mode Flag supplied by Anthony Naggs)




EXT   Extract bit field (NEC V20/30 only)
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