Intel 253666-024US User Manual

Page 143

Vol. 2A 3-97

INSTRUCTION SET REFERENCE, A-M

CALL—Call Procedure

tempEIP ← DEST(Offset);

IF OperandSize

THEN tempEIP ← tempEIP AND 0000FFFFH; FI; (* Clear upper 16 bits *)

IF (EFER.LMA = 0 or target mode = Compatibility mode) and (tempEIP outside new code

segment limit)

THEN #GP(0); FI;

IF tempEIP is non-canonical

THEN #GP(0); FI;

IF OperandSize

THEN

Push(CS); (* Padded with 16 high-order bits *)
Push(EIP);
CS ← DEST(CodeSegmentSelector);

(* Segment descriptor information also loaded *)
CS(RPL) ← CPL;

EIP ← tempEIP;

ELSE

IF OperandSize = 16

THEN

Push(CS);
Push(IP);
CS ← DEST(CodeSegmentSelector);

(* Segment descriptor information also loaded *)
CS(RPL) ← CPL;

EIP ← tempEIP;

ELSE (* OperandSize = 64 *)

Push(CS); (* Padded with 48 high-order bits *)
Push(RIP);
CS ← DEST(CodeSegmentSelector);

(* Segment descriptor information also loaded *)
CS(RPL) ← CPL;

RIP ← tempEIP;

FI;

END;

CALL-GATE:

IF call gate (DPL < CPL) or (RPL > DPL)

THEN #GP(call gate selector); FI;

IF call gate not present

THEN #NP(call gate selector); FI;

IF call gate code-segment selector is NULL

THEN #GP(0); FI;

IF call gate code-segment selector index is outside descriptor table limits