Assembly Language Programming - Fundamentals of Computer Organization and Architecture - page 49

Figure 3.6 The base register sets of the X86 programming model

31 18 17 16 15 14 13 12 11 10 9 8 7 6543 2 1 0

Reserved AG VM RF 0 NT IOPL ODITSZ A P C

Figure 3.7 The X86 flag register

TABLE 3.8 X86 Status Flags

Flag Meaning Processor Flag Meaning Processor

C Carry All P Parity All

A Auxiliary All Z Zero All

S Sign All T Trap All

I Interrupt All D Direction All

O Overflow All IOPL I / O privilege level 286

NT Nested task 286 RF Resume 386

VM Virtual mode 386 AC Alignment check 486