Intel 64 and IA-32 Architectures Software Developers Manual Volume 2A, Instruction Set Reference, A-M

Vol. 2 3-449
INSTRUCTION SET REFERENCE, A-M
Operation
IF SRC = 0
THEN #DE; (* Divide error *)
FI;
IF OperandSize
= 8 (* Word/byte operation *)
THEN
temp ← AX / SRC; (* Signed division *)
IF (temp > 7FH) or (temp < 80H)
(* If a positive result is greater than 7FH or a negative result is less than 80H *)
THEN #DE; (* Divide error *)
ELSE
AL ← temp;
AH ← AX SignedModulus SRC;
FI;
ELSE IF OperandSize
= 16 (* Doubleword/word operation *)
THEN
temp ← DX:AX / SRC; (* Signed division *)
IF (temp > 7FFFH) or (temp < 8000H)
(* If a positive result is greater than 7FFFH
or a negative result is less than 8000H *)
THEN
#DE; (* Divide error *)
ELSE
AX ← temp;
DX ← DX:AX SignedModulus SRC;
FI;
FI;
ELSE IF OperandSize = 32 (* Quadword/doubleword operation *)
temp ← EDX:EAX / SRC; (* Signed division *)
IF (temp > 7FFFFFFFH) or (temp < 80000000H)
Table 3-55. IDIV Results
Operand Size Dividend Divisor Quotient Remainder Quotient Range
Word/byte AX r/m8 AL AH −128 to +127
Doubleword/word DX:AX r/m16 AX DX −32,768 to
+32,767
Quadword/doubleword EDX:EAX r/m32 EAX EDX −2
31
to 2
32
− 1
Doublequadword/
quadword
RDX:RAX r/m64 RAX RDX −2
63
to 2
64
− 1