AMD K5

Control Register 4 (CR4) Extensions 3-19
18524C/0—Nov1996 AMD-K5 Processor Technical Reference Manual
Table 3-5D. Instructions that Modify the IF or VIF Flags—Virtual-8086 Mode Interrupt
Extensions (VME)
1
TYPE PE VM VME PVI IOPL GP(0) IF VIF
CLI 111— 3NoIF ← 0 No Change
CLI 111—< 3 No No Change VIF ← 0
STI 1 1 1 — 3 No IF ← 1 No Change
STI 1 1 1 — < 3
No
3
No Change VIF ← 1
PUSHF 1 1 1 — 3 No Pushed Not Pushed
PUSHF 111—< 3 No Not Pushed Pushed into IF
PUSHFD 1 1 1 — 3 No Pushed Pushed
PUSHFD 111—< 3Yes — —
POPF 1 1 1 — 3 No Popped Not Popped
POPF 1 1 1 — < 3 No Not Popped Popped from IF
POPFD 1 1 1 — 3 No Popped Not Popped
POPFD 1 1 1 — < 3Yes — —
IRET from
V86 Mode
1 1 1 — 3 No Popped Not Popped
IRET from
V86 Mode
111—< 3
No
3
Not Popped Popped from IF
IRETD from
V86 Mode
1 1 1 — 3 No Popped Not Popped
IRETD from
V86 Mode
111—< 3Yes — —
IRETD from
Protected Mode
2
111——
No
3
Popped Popped
Notes:
1. All Virtual-8086 mode tasks run at CPL = 3.
2. All protected virtual interrupt handlers run at CPL = 0.
3. GP(0) if an attempt is made to set VIF when VIP = 1.
— Not applicable.