24531904_j

INT n/INTO/INT 3—Call to Interrupt Procedure ( 続き )
操作
以下の操作の記述は、 INT n 命令お よ び INTO 命令だけでな く 、 外部割 り 込みお よ び例外
にも適用される。
IF Itanium System EnvironmentTHEN
IF INT3 Form THEN IA-32_Exception(3);
IF INTO Form THEN IA-32_Exception(4);
IF INT Form THEN IA-32_Interrupt(N);
FI;
/*IN the Itanium System Environment all of the following operations are intercepted*/
IF PE=0
THEN
GOTO REAL-ADDRESS-MODE;
ELSE (* PE=1 *)
GOTO PROTECTED-MODE;
FI;
REAL-ADDRESS-MODE:
IF ((DEST ∗ 4) + 3) is not within IDT limit THEN #GP; FI;
IF stack not large enough for a 6-byte return information THEN #SS; FI;
Push (EFLAGS[15:0]);
IF ← 0; (* Clear interrupt flag *)
TF ← 0; (* Clear trap flag *)
AC ← 0; (*Clear AC flag*)
Push(CS);
Push(IP);
(* No error codes are pushed *)
CS ← IDT(Descriptor (vector ∗ 4), selector));
EIP ← IDT(Descriptor (vector ∗ 4), offset)); (* 16 bit offset AND 0000FFFFH *)
END;
PROTECTED-MODE:
IF ((DEST ∗ 8) + 7) is not within IDT limits
OR selected IDT descriptor is not an interrupt-, trap-, or task-gate type
THEN #GP((DEST ∗ 8) + 2 + EXT);
(* EXT is bit 0 in error code *)
FI;
IF software interrupt (* generated by INTn, INT3, or INTO *)
THEN
IF gate descriptor DPL < CPL
THEN #GP((vector number ∗ 8) + 2 );
(* PE=1, DPL