Operation

IF instruction = relative JMP (* i.e. operand is rel8, rel16, or rel32 *)
THEN
EIP EIP + rel18/16/32;
IF OperandSize = 16
THEN EIP EIP AND 0000FFFFH;
FI;
FI;

IF instruction = near indirect JMP
(* i.e. operand is r/m16 or r/m32 *)
THEN
IF OperandSize = 16
THEN
EIP [r/m16] AND 0000FFFFH;
ELSE (* OperandSize = 32 *)
EIP [r/m32;
FI;
FI;

IF (PE = 0 OR (PE = 1 AND VM = 1)) (* real mode or V86 mode *)
AND instruction = far JMP
(* i.e., operand type is m16:16, m16:32, ptr16:16, ptr16:32 *)
THEN GOTO REAL-OR-V86-MODE;
IF operand type = m16:16 or m16:32
THEN (* indirect *)
IF OperandSize = 16
THEN
CS:IP [m16:16];
EIP EIP AND 0000FFFFH; (* clear upper 16 bits *)
ELSE (* OperandSize = 32 *)
CS:EIP [m16:32];
FI;
FI;
IF operand type = ptr16:16 or ptr16:32
THEN
IF OperandSize = 16
THEN
CS:IP ptr16:16;
EIP EIP AND 0000FFFFH; (* clear upper 16 bits *)
ELSE (* OperandSize = 32 *)
CS:EIP ptr16:32;
FI;
FI;
FI;

IF (PE = 1 AND VM = 0) (* Protected mode, not V86 mode *)
AND instruction = far JMP
THEN
IF operand type = m16:16 or m16:32
THEN (* indirect *)
check access of EA dword;
#GP(0) or #SS(0) IF limit violation;
FI;
Destination selector is not null ELSE #GP(0)
Destination selector index is within its descriptor table limits ELSE #GP(selector)
Depending on AR byte of destination descriptor;
GOTO CONFORMING-CODE-SEGMENT;
GOTO NONCONFORMING-CODE-SEGMENT;
GOTO CALL-GATE;
GOTO TASK-GATE;
GOTO TASK-STATE-SEGMENT;
ELSE #GP(selector); (* illegal AR byte in descriptor *)
FI;

CONFORMING-CODE-SEGMENT:
Descriptor DPL must be ≤ CPL ELSE #GP(selector);
Segment must be present ELSE #NP(selector);
Instruction pointer must be within code-segment limit ELSE #GP(0);
IF OperandSize = 32
THEN Load CS:EIP from destination pointer;
ELSE Load CS:IP from destination pointer;
FI;
Load CS register with new segment descriptor;

NONCONFORMING-CODE-SEGMENT:
RPL of destination selector must be ≥ CPL ELSE #GP(selector);
Descriptor DPL must be = CPL ELSE #GP(selector);
Segment must be present ELSE #NP(selector);
Instruction pointer must be within code-segment limit ELSE #GP(0);
IF OperandSize = 32
THEN Load CS:EIP from destination pointer;
ELSE Load CS:IP from destination pointer;
FI;
Load CS register with new segment descriptor;
Set RPL field of CS register to CPL;

CALL-GATE:
Descriptor DPL must be ≥ CPL ELSE #GP(gate selector);
Descriptor DPL must be ≥ gate selector RPL ELSE #GP(gate selector);
Gate must be present ELSE #NP(gate selector);
Examine selector to code segment given in call gate descriptor:
Selector must not be null ELSE #GP(0);
Selector must be within its descriptor table limits ELSE
#GP(CS selector);
Descriptor AR byte must indicate code segment
ELSE #GP(CS selector);
IF non-conforming
THEN code-segment descriptor DPL must = CPL
ELSE #GP(CS selector);
FI;
IF conforming
THEN code-segment descriptor DPL must be ≤ CPL;
ELSE #GP(CS selector);
Code segment must be present ELSE #NP(CS selector);
Instruction pointer must be within code-segment limit ELSE #GP(0);
IF OperandSize = 32
THEN Load CS:EIP from call gate;
ELSE Load CS:IP from call gate;
FI;
Load CS register with new code-segment descriptor;
Set RPL of CS to CPL

TASK-GATE:
Gate descriptor DPL must be ≥ CPL ELSE #GP(gate selector);
Gate descriptor DPL must be ≥ gate selector RPL ELSE #GP(gate selector);
Task Gate must be present ELSE #NP(gate selector);
Examine selector to TSS, given in Task Gate descriptor:
Must specify global in the local/global bit ELSE #GP(TSS selector);
Index must be within GDT limits ELSE #GP(TSS selector);
Descriptor AR byte must specify available TSS (bottom bits 00001);
ELSE #GP(TSS selector);
Task State Segment must be present ELSE #NP(TSS selector);
SWITCH-TASKS (without nesting) to TSS;
Instruction pointer must be within code-segment limit ELSE #GP(0);

TASK-STATE-SEGMENT:
TSS DPL must be ≥ CPL ELSE #GP(TSS selector);
TSS DPL must be ≥ TSS selector RPL ELSE #GP(TSS selector);
Descriptor AR byte must specify available TSS (bottom bits 00001)
ELSE #GP(TSS selector);
Task State Segment must be present ELSE #NP(TSS selector);
SWITCH-TASKS (without nesting) to TSS;
Instruction pointer must be within code-segment limit ELSE #GP(0);

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