x86 instruction listings

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The x86 instruction set has been extended several times, introducing wider registers and datatypes as well as new functionality[1]

x86 integer instructions[edit]

This is the full 8086/8088 instruction set, most, if not all of these instructions are available in 32-bit mode, they just operate on 32-bit registers (eax, ebx, etc.) and values instead of their 16-bit (ax, bx, etc.) counterparts. See also x86 assembly language for a quick tutorial for this processor family. The updated instruction set is also grouped according to architecture (i386, i486, i686) and more generally is referred to as x86_32 and x86_64 (also known as AMD64).

Original 8086/8088 instructions[edit]

Original 8086/8088 instruction set
Instruction Meaning Notes Opcode
AAA ASCII adjust AL after addition used with unpacked binary coded decimal 0x37
AAD ASCII adjust AX before division 8086/8088 datasheet documents only base 10 version of the AAD instruction (opcode 0xD5 0x0A), but any other base will work. Later Intel's documentation has the generic form too. NEC V20 and V30 (and possibly other NEC V-series CPUs) always use base 10, and ignore the argument, causing a number of incompatibilities 0xD5
AAM ASCII adjust AX after multiplication Only base 10 version (Operand is 0xA) is documented, see notes for AAD 0xD4
AAS ASCII adjust AL after subtraction 0x3f
ADC Add with carry destination := destination + source + carry_flag
ADD Add (1) r/m += r/imm; (2) r += m/imm; 0x00…0x05, 0x80/0…0x83/0
AND Logical AND (1) r/m &= r/imm; (2) r &= m/imm;
CALL Call procedure push eip; eip points to the instruction directly after the call
CBW Convert byte to word 0x98
CLC Clear carry flag CF = 0; 0xF8
CLD Clear direction flag DF = 0; 0xFC
CLI Clear interrupt flag IF = 0; 0xFA
CMC Complement carry flag 0xF5
CMP Compare operands
CMPSB Compare bytes in memory 0xA6
CMPSW Compare words 0xA7
CWD Convert word to doubleword 0x99
DAA Decimal adjust AL after addition (used with packed binary coded decimal) 0x27
DAS Decimal adjust AL after subtraction 0x2F
DEC Decrement by 1
DIV Unsigned divide DX:AX = DX:AX / r/m; resulting DX = remainder
ESC Used with floating-point unit
HLT Enter halt state 0xF4
IDIV Signed divide DX:AX = DX:AX / r/m; resulting DX = remainder
IMUL Signed multiply (1) DX:AX = AX * r/m; (2) AX = AL * r/m
IN Input from port (1) AL = port[imm]; (2) AL = port[DX]; (3) AX = port[DX];
INC Increment by 1
INT Call to interrupt
INTO Call to interrupt if overflow 0xCE
IRET Return from interrupt
Jcc Jump if condition (JA, JAE, JB, JBE, JC, JE, JG, JGE, JL, JLE, JNA, JNAE, JNB, JNBE, JNC, JNE, JNG, JNGE, JNL, JNLE, JNO, JNP, JNS, JNZ, JO, JP, JPE, JPO, JS, JZ)
JCXZ Jump if CX is zero 0xE3
JMP Jump
LAHF Load FLAGS into AH register 0x9F
LDS Load pointer using DS 0xC5
LEA Load Effective Address 0x8D
LES Load ES with pointer 0xC4
LOCK Assert BUS LOCK# signal (for multiprocessing) 0xF0
LODSB Load string byte if (DF==0) AL = *SI++; else AL = *SI--; 0xAC
LODSW Load string word if (DF==0) AX = *SI++; else AX = *SI--; 0xAD
LOOP/LOOPx Loop control (LOOPE, LOOPNE, LOOPNZ, LOOPZ) if (x && --CX) goto lbl;
MOV Move copies data from one location to another, (1) r/m = r; (2) r = r/m;
MOVSB Move byte from string to string if (DF==0) *(byte*)DI++ = *(byte*)SI++; else *(byte*)DI-- = *(byte*)SI--; 0xA4
MOVSW Move word from string to string if (DF==0) *(word*)DI++ = *(word*)SI++; else *(word*)DI-- = *(word*)SI--; 0xA5
MUL Unsigned multiply (1) DX:AX = AX * r/m; (2) AX = AL * r/m;
NEG Two's complement negation r/m *= -1;
NOP No operation opcode equivalent to XCHG EAX, EAX, but it is never optimized to "nothing happens", always using a fixed number of processor ticks 0x90
NOT Negate the operand, logical NOT r/m ^= -1;
OR Logical OR (1) r/m |= r/imm; (2) r |= m/imm;
OUT Output to port (1) port[imm] = AL; (2) port[DX] = AL; (3) port[DX] = AX;
POP Pop data from stack r/m = *SP++; POP CS (opcode 0x0F) works only on 8086/8088. Later CPUs use 0x0F as a prefix for newer instructions.
POPF Pop data from flags register FLAGS = *SP++; 0x9D
PUSH Push data onto stack *--SP = r/m;
PUSHF Push FLAGS onto stack *--SP = FLAGS; 0x9C
RCL Rotate left (with carry)
RCR Rotate right (with carry)
REPxx Repeat MOVS/STOS/CMPS/LODS/SCAS (REP, REPE, REPNE, REPNZ, REPZ)
RET Return from procedure Not a real instruction. The assembler will translate these to a RETN or a RETF depending on the memory model of the target system.
RETN Return from near procedure
RETF Return from far procedure
ROL Rotate left
ROR Rotate right
SAHF Store AH into FLAGS 0x9E
SAL Shift Arithmetically left (signed shift left) (1) r/m <<= 1; (2) r/m <<= CL;
SAR Shift Arithmetically right (signed shift right) (1) (signed)r/m >>= 1; (2) (signed)r/m >>= CL;
SBB Subtraction with borrow alternative 1-byte encoding of SBB AL, AL is available via undocumented SALC instruction
SCASB Compare byte string 0xAE
SCASW Compare word string 0xAF
SHL Shift left (unsigned shift left)
SHR Shift right (unsigned shift right)
STC Set carry flag CF = 1; 0xF9
STD Set direction flag DF = 1; 0xFD
STI Set interrupt flag IF = 1; 0xFB
STOSB Store byte in string if (DF==0) *ES:DI++ = AL; else *ES:DI-- = AL; 0xAA
STOSW Store word in string if (DF==0) *ES:DI++ = AX; else *ES:DI-- = AX; 0xAB
SUB Subtraction (1) r/m -= r/imm; (2) r -= m/imm;
TEST Logical compare (AND) (1) r/m & r/imm; (2) r & m/imm;
WAIT Wait until not busy Waits until BUSY# pin is inactive (used with floating-point unit) 0x9B
XCHG Exchange data r :=: r/m; A spinlock typically uses xchg as an atomic operation. (coma bug).
XLAT Table look-up translation behaves like MOV AL, [BX+AL] 0xD7
XOR Exclusive OR (1) r/m ^= r/imm; (2) r ^= m/imm;

Added in specific processors[edit]

Added with 80186/80188[edit]

Instruction Meaning Notes
BOUND Check array index against bounds raises software interrupt 5 if test fails
ENTER Enter stack frame Modifies stack for entry to procedure for high level language. Takes two operands: the amount of storage to be allocated on the stack and the nesting level of the procedure.
INS Input from port to string equivalent to
IN (E)AX, DX
MOV ES:[(E)DI], (E)AX
; adjust (E)DI according to operand size and DF
LEAVE Leave stack frame Releases the local stack storage created by the previous ENTER instruction.
OUTS Output string to port equivalent to
MOV (E)AX, DS:[(E)SI]
OUT DX, (E)AX
; adjust (E)SI according to operand size and DF
POPA Pop all general purpose registers from stack equivalent to
POP DI
POP SI
POP BP
POP AX ;no POP SP here, only ADD SP,2
POP BX
POP DX
POP CX
POP AX
PUSHA Push all general purpose registers onto stack equivalent to
PUSH AX
PUSH CX
PUSH DX
PUSH BX
PUSH SP
PUSH BP
PUSH SI
PUSH DI
PUSH immediate Push an immediate byte/word value onto the stack equivalent to
PUSH 12h
PUSH 1200h
IMUL immediate Unsigned multiplication of immediate byte/word value equivalent to
IMUL 12h
IMUL 1200h
SHL/SHR/ROL/ROR/RCL/RCR immediate Rotate/shift bits with an immediate value greater than 1 equivalent to
ROL AX,3
SHR BL,3

Added with 80286[edit]

Instruction Meaning Notes
ARPL Adjust RPL field of selector
CLTS Clear task-switched flag in register CR0
LAR Load access rights byte
LGDT Load global descriptor table
LIDT Load interrupt descriptor table
LLDT Load local descriptor table
LMSW Load machine status word
LOADALL Load all CPU registers, including internal ones such as GDT Undocumented, 80286 and 80386 only
LSL Load segment limit
LTR Load task register
SGDT Store global descriptor table
SIDT Store interrupt descriptor table
SLDT Store local descriptor table
SMSW Store machine status word
STR Store task register
VERR Verify a segment for reading
VERW Verify a segment for writing

Added with 80386[edit]

Instruction Meaning Notes
BSF Bit scan forward
BSR Bit scan reverse
BT Bit test
BTC Bit test and complement
BTR Bit test and reset
BTS Bit test and set
CDQ Convert double-word to quad-word Sign-extends EAX into EDX, forming the quad-word EDX:EAX. Since (I)DIV uses EDX:EAX as its input, CDQ must be called after setting EAX if EDX is not manually initialized (as in 64/32 division) before (I)DIV.
CMPSD Compare string double-word Compares ES:[(E)DI] with DS:[SI]
CWDE Convert word to double-word Unlike CWD, CWDE sign-extends AX to EAX instead of AX to DX:AX
INSD Input from port to string double-word
IRETx Interrupt return; D suffix means 32-bit return, F suffix means do not generate epilogue code (i.e. LEAVE instruction) Use IRETD rather than IRET in 32-bit situations
JECXZ Jump if ECX is zero
LFS, LGS Load far pointer
LSS Load stack segment
LODSD Load string double-word can be prefixed with REP
LOOPW, LOOPccW Loop, conditional loop Same as LOOP, LOOPcc for earlier processors
LOOPD, LOOPccD Loop while equal if (cc && --ECX) goto lbl;, cc = Z(ero), E(qual), NonZero, N(on)E(qual)
MOV to/from CR/DR/TR Move to/from special registers CR=control registers, DR=debug registers, TR=test registers (up to 80486)
MOVSD Move string double-word *(dword*)ES:EDI±± = (dword*)ESI±±; (±± depends on DF)
MOVSX Move with sign-extension (long)r = (signed char) r/m; and similar
MOVZX Move with zero-extension (long)r = (unsigned char) r/m; and similar
OUTSD Output to port from string double-word port[DX] = *(long*)ESI±±; (±± depends on DF)
POPAD Pop all double-word (32-bit) registers from stack Does not pop register ESP off of stack
POPFD Pop data into EFLAGS register
PUSHAD Push all double-word (32-bit) registers onto stack
PUSHFD Push EFLAGS register onto stack
SCASD Scan string data double-word
SETcc Set byte to one on condition, zero otherwise (SETA, SETAE, SETB, SETBE, SETC, SETE, SETG, SETGE, SETL, SETLE, SETNA, SETNAE, SETNB, SETNBE, SETNC, SETNE, SETNG, SETNGE, SETNL, SETNLE, SETNO, SETNP, SETNS, SETNZ, SETO, SETP, SETPE, SETPO, SETS, SETZ)
SHLD Shift left double-word
SHRD Shift right double-word r1 = r1>>CL ∣ r2<<(32-CL); Instead of CL, immediate 1 can be used
STOSD Store string double-word *ES:EDI±± = EAX; (±± depends on DF, ES cannot be overridden)

Added with 80486[edit]

Instruction Meaning Notes
BSWAP Byte Swap r = r<<24 | r<<8&0x00FF0000 | r>>8&0x0000FF00 | r>>24; Only works for 32 bit registers
CMPXCHG atomic CoMPare and eXCHanGe See Compare-and-swap / on later 80386 as undocumented opcode available
INVD Invalidate Internal Caches Flush internal caches
INVLPG Invalidate TLB Entry Invalidate TLB Entry for page that contains data specified
WBINVD Write Back and Invalidate Cache Writes back all modified cache lines in the processor's internal cache to main memory and invalidates the internal caches.
XADD eXchange and ADD Exchanges the first operand with the second operand, then loads the sum of the two values into the destination operand.

Added with Pentium[edit]

Instruction Meaning Notes
CPUID CPU IDentification Returns data regarding processor identification and features, and returns data to the EAX, EBX, ECX, and EDX registers. Instruction functions specified by the EAX register.[1] This was also added to later 80486 processors
CMPXCHG8B CoMPare and eXCHanGe 8 bytes Compare EDX:EAX with m64. If equal, set ZF and load ECX:EBX into m64. Else, clear ZF and load m64 into EDX:EAX.
RDMSR ReaD from Model-specific register Load MSR specified by ECX into EDX:EAX
RDTSC ReaD Time Stamp Counter Returns the number of processor ticks since the processor being "ONLINE" (since the last power on of system)
WRMSR WRite to Model-Specific Register Write the value in EDX:EAX to MSR specified by ECX
RSM [1] Resume from System Management Mode This was introduced by the i386SL and later and is also in the i486SL and later. Resumes from System Management Mode (SMM)

Added with Pentium MMX[edit]

Instruction Meaning Notes
RDPMC Read the PMC [Performance Monitoring Counter] Specified in the ECX register into registers EDX:EAX

Also MMX registers and MMX support instructions were added. They are usable for both integer and floating point operations, see below.

Added with AMD K6[edit]

Instruction Meaning Notes
SYSCALL functionally equivalent to SYSENTER
SYSRET functionally equivalent to SYSEXIT

AMD changed the CPUID detection bit for this feature from the K6-II on.

Added with Pentium Pro[edit]

Instruction Meaning Notes
CMOVcc Conditional move (CMOVA, CMOVAE, CMOVB, CMOVBE, CMOVC, CMOVE, CMOVG, CMOVGE, CMOVL, CMOVLE, CMOVNA, CMOVNAE, CMOVNB, CMOVNBE, CMOVNC, CMOVNE, CMOVNG, CMOVNGE, CMOVNL, CMOVNLE, CMOVNO, CMOVNP, CMOVNS, CMOVNZ, CMOVO, CMOVP, CMOVPE, CMOVPO, CMOVS, CMOVZ)
SYSENTER SYStem call ENTER
SYSEXIT SYStem call EXIT
UD2 Undefined Instruction Generates an invalid opcode. This instruction is provided for software testing to explicitly generate an invalid opcode. The opcode for this instruction is reserved for this purpose.

Added with SSE[edit]

Instruction Meaning Notes
MASKMOVQ Masked Move of Quadword Selectively write bytes from mm1 to memory location using the byte mask in mm2
MOVNTPS Move Aligned Four Packed Single-FP Non Temporal Move packed single-precision floating-point values from xmm to m128, minimizing pollution in the cache hierarchy.
MOVNTQ Move Quadword Non-Temporal
PREFETCH0 Prefetch Data from Address Prefetch into all cache levels
PREFETCH1 Prefetch Data from Address Prefetch into all cache levels EXCEPT L1
PREFETCH2 Prefetch Data from Address Prefetch into all cache levels EXCEPT L1 and L2
PREFETCHNTA Prefetch Data from Address Prefetch into all cache levels to non-temporal cache structure
SFENCE Store Fence Processor hint to make sure all store operations that took place prior to the SFENCE call are globally visible

Added with SSE2[edit]

Instruction Meaning Notes
CLFLUSH Cache Line Flush Invalidates the cache line that contains the linear address specified with the source operand from all levels of the processor cache hierarchy
LFENCE Load Fence Serializes load operations.
MASKMOVDQU Masked Move of Double Quadword Unaligned Stores selected bytes from the source operand (first operand) into a 128-bit memory location
MFENCE Memory Fence Performs a serializing operation on all load and store instructions that were issued prior the MFENCE instruction.
MOVNTDQ Move Double Quadword Non-Temporal Move double quadword from xmm to m128, minimizing pollution in the cache hierarchy.
MOVNTI Move Doubleword Non-Temporal Move doubleword from r32 to m32, minimizing pollution in the cache hierarchy.
MOVNTPD Move Packed Double-Precision Floating-Point Values Non-Temporal Move packed double-precision floating-point values from xmm to m128, minimizing pollution in the cache hierarchy.
PAUSE Provides a hint to the processor that the following code is a spin loop for cacheability

Added with SSE3[edit]

Instruction Meaning Notes
LDDQU Load Unaligned Integer 128 bits Instructionally equivalent to MOVDQU. Used for video encoding.
MONITOR EAX, ECX, EDX Setup Monitor Address Sets up a linear address range to be monitored by hardware and activates the monitor.
MWAIT EAX, ECX Monitor Wait Processor hint to stop instruction execution and enter an implementation-dependent optimized state until occurrence of a class of events.

Added with x86-64[edit]

Instruction Meaning Notes
CDQE Sign extend EAX into RAX
CQO Sign extend RAX into RDX:RAX
CMPSQ CoMPare String Quadword
CMPXCHG16B CoMPare and eXCHanGe 16 Bytes
IRETQ 64-bit Return from Interrupt
JRCXZ Jump if RCX is zero
LODSQ LOaD String Quadword
MOVSXD MOV with Sign Extend 32-bit to 64-bit
POPFQ POP RFLAGS Register
PUSHFQ PUSH RFLAGS Register
RDTSCP ReaD Time Stamp Counter and Processor ID
SCASQ SCAn String Quadword
STOSQ STOre String Quadword
SWAPGS Exchange GS base with KernelGSBase MSR

Added with AMD-V[edit]

Instruction Meaning Notes
CLGI Clear Global Interrupt Flag Clears the GIF
INVLPGA Invalidate TLB entry in a specified ASID Invalidates the TLB mapping for the virtual page specified in RAX and the ASID specified in ECX.
MOV(CRn) Move to or from control registers Moves 32- or 64-bit contents to control register and vice versa.
SKINIT Secure Init and Jump with Attestation Verifiable startup of trusted software based on secure hash comparison
STGI Set Global Interrupt Flag Sets the GIF.
VMLOAD Load state From VMCB Loads a subset of processor state from the VMCB specified by the physical address in the RAX register.
VMMCALL Call VMM Used exclusively to communicate with VMM
VMRUN Run virtual machine Performs a switch to the guest OS.
VMSAVE Save state To VMCB Saves additional guest state to VMCB.

Added with Intel VT-x[edit]

VMPTRLD, VMPTRST, VMCLEAR, VMREAD, VMWRITE, VMCALL, VMLAUNCH, VMRESUME, VMXOFF, VMXON

Added with SSE4a[edit]

LZCNT, POPCNT (POPulation CouNT) - advanced bit manipulation

x87 floating-point instructions[edit]

Original 8087 instructions[edit]

Instruction Meaning Notes
F2XM1 (2^x) - 1 more precise than 2^x for x close to zero
FABS Absolute value
FADD Add
FADDP Add and pop
FBLD Load BCD
FBSTP Store BCD and pop
FCHS Change sign
FCLEX Clear exceptions
FCOM Compare
FCOMP Compare and pop
FCOMPP Compare and pop twice
FDECSTP Decrement floating point stack pointer
FDISI Disable interrupts 8087 only, otherwise FNOP
FDIV Divide Pentium FDIV bug
FDIVP Divide and pop
FDIVR Divide reversed
FDIVRP Divide reversed and pop
FENI Enable interrupts 8087 only, otherwise FNOP
FFREE Free register
FIADD Integer add
FICOM Integer compare
FICOMP Integer compare and pop
FIDIV Integer divide
FIDIVR Integer divide reversed
FILD Load integer
FIMUL Integer multiply
FINCSTP Increment floating point stack pointer
FINIT Initialize floating point processor
FIST Store integer
FISTP Store integer and pop
FISUB Integer subtract
FISUBR Integer subtract reversed
FLD Floating point load
FLD1 Load 1.0 onto stack
FLDCW Load control word
FLDENV Load environment state
FLDENVW Load environment state, 16-bit
FLDL2E Load log2(e) onto stack
FLDL2T Load log2(10) onto stack
FLDLG2 Load log10(2) onto stack
FLDLN2 Load ln(2) onto stack
FLDPI Load π onto stack
FLDZ Load 0.0 onto stack
FMUL Multiply
FMULP Multiply and pop
FNCLEX Clear exceptions, no wait
FNDISI Disable interrupts, no wait 8087 only, otherwise FNOP
FNENI Enable interrupts, no wait 8087 only, otherwise FNOP
FNINIT Initialize floating point processor, no wait
FNOP No operation
FNSAVE Save FPU state, no wait, 8-bit
FNSAVEW Save FPU state, no wait, 16-bit
FNSTCW Store control word, no wait
FNSTENV Store FPU environment, no wait
FNSTENVW Store FPU environment, no wait, 16-bit
FNSTSW Store status word, no wait
FPATAN Partial arctangent
FPREM Partial remainder
FPTAN Partial tangent
FRNDINT Round to integer
FRSTOR Restore saved state
FRSTORW Restore saved state Perhaps not actually available in 8087
FSAVE Save FPU state
FSAVEW Save FPU state, 16-bit
FSCALE Scale by factor of 2
FSQRT Square root
FST Floating point store
FSTCW Store control word
FSTENV Store FPU environment
FSTENVW Store FPU environment, 16-bit
FSTP Store and pop
FSTSW Store status word
FSUB Subtract
FSUBP Subtract and pop
FSUBR Reverse subtract
FSUBRP Reverse subtract and pop
FTST Test for zero
FWAIT Wait while FPU is executing
FXAM Examine condition flags
FXCH Exchange registers
FXTRACT Extract exponent and significand
FYL2X y * log2 x if y = logb 2, then the base-b logarithm is computed
FYL2XP1 y * log2 (x+1) more precise than log2 z if x is close to zero

Added in specific processors[edit]

Added with 80287[edit]

Instruction Meaning Notes
FSETPM Set protected mode 80287 only, otherwise FNOP

Added with 80387[edit]

Instruction Meaning Notes
FCOS Cosine
FLDENVD Load environment state, 32-bit
FSAVED Save FPU state, 32-bit
FSTENVD Store FPU environment, 32-bit
FPREM1 Partial remainder Computes IEEE remainder
FRSTORD Restore saved state, 32-bit
FSIN Sine
FSINCOS Sine and cosine
FSTENVD Store FPU environment, 32-bit
FUCOM Unordered compare
FUCOMP Unordered compare and pop
FUCOMPP Unordered compare and pop twice

Added with Pentium Pro[edit]

  • FCMOV variants: FCMOVB, FCMOVBE, FCMOVE, FCMOVNB, FCMOVNBE, FCMOVNE, FCMOVNU, FCMOVU
  • FCOMI variants: FCOMI, FCOMIP, FUCOMI, FUCOMIP

Added with SSE[edit]

FXRSTOR, FXSAVE

These are also supported on later Pentium IIs which do not contain SSE support

Added with SSE3[edit]

FISTTP (x87 to integer conversion with truncation regardless of status word)

Undocumented x87 instructions[edit]

FFREEP performs FFREE ST(i) and pop stack

SIMD instructions[edit]

MMX instructions[edit]

Added with Pentium MMX[edit]

Instruction Meaning Notes
EMMS Empty MMX Technology State Marks all x87 FPU registers for use by FPU
MOVD mm, r/m32 Move doubleword
MOVQ mm, r/m64 Move quadword
PACKSSDW mm1, mm2/m64 Pack doubleword to word (signed with saturation)
PACKSSWB mm1, mm2/m64 Pack word to byte (signed with saturation)
PACKUSWB mm1, mm2/m64 Pack word to byte (signed with unsaturation)
PADDB mm, mm/m64 Add packed byte integers
PADDW mm, mm/m64 Add packed word integers
PADDD mm, mm/m64 Add packed doubleword integers
PADDSB mm, mm/m64 Add packed signed byte integers and saturate
PADDSW mm, mm/m64 Add packed signed word integers and saturate
PADDUSB mm, mm/m64 Add packed unsigned byte integers and saturate
PADDUSW mm, mm/m64 Add packed unsigned word integers and saturate
PAND mm, mm/m64 Bitwise AND
PANDN mm, mm/m64 Bitwise AND NOT
POR mm, mm/m64 Bitwise OR
PXOR mm, mm/m64 Bitwise XOR
PCMPEQB mm, mm/m64 Compare packed byte integers for equality
PCMPEQW mm, mm/m64 Compare packed word integers for equality
PCMPEQD mm, mm/m64 Compare packed doubleword integers for equality
PCMPGTB mm, mm/m64 Compare packed signed byte integers for greater than
PCMPGTW mm, mm/m64 Compare packed signed word integers for greater than
PCMPGTD mm, mm/m64 Compare packed signed doubleword integers for greater than
PMADDWD mm, mm/m64 Multiply packed wordi ntegers, add adjacent doubleword results
PMULHW mm, mm/m64 Multiply packed signed word integers, store high 16 bit results
PMULLW mm, mm/m64 Multiply packed signed word integers, store low 16 bit results
PSLLW mm, mm/m64 Shift left word, shift in zeros
PSLLD mm, mm/m64 Shift left doubleword, shift in zeros
PSLLQ mm, mm/m64 Shift left quadword, shift in zeros
PSRAD mm, mm/m64 Shift right doubleword, shift in sign bits
PSRAW mm, mm/m64 Shift right word, shift in sign bits
PSRLW mm, mm/m64 Shift right word, shift in zeros
PSRLD mm, mm/m64 Shift right doubleword, shift in zeros
PSRLQ mm, mm/m64 Shift right quadword, shift in zeros
PSUBB mm, mm/m64 Subtract packed byte integers
PSUBW mm, mm/m64 Subtract packed word integers
PSUBD mm, mm/m64 Subtract packed doubleword integers
PSUBSB mm, mm/m64 Subtract packed signed byte integers with saturation
PSUBSW mm, mm/m64 Subtract packed signed word integers with saturation
PSUBUSB mm, mm/m64 Subtract packed unsigned byte integers with saturation
PSUBUSW mm, mm/m64 Subtract packed unsigned word integers with saturation
PUNPCKHBW mm, mm/m64 Unpack and interleave high-order bytes
PUNPCKHWD mm, mm/m64 Unpack and interleave high-order words
PUNPCKHDQ mm, mm/m64 Unpack and interleave high-order doublewords
PUNPCKLBW mm, mm/m64 Unpack and interleave low-order bytes
PUNPCKLDQ mm, mm/m64 Unpack and interleave low-order words
PUNPCKLWD mm, mm/m64 Unpack and interleave low-order doublewords

MMX+ instructions[edit]

Added with Athlon[edit]

Same as the SSE SIMD integer instructions which operated on MMX registers.

EMMX instructions[edit]

EMMI instructions[edit]

(added with 6x86MX from Cyrix, deprecated now)

PAVEB, PADDSIW, PMAGW, PDISTIB, PSUBSIW, PMVZB, PMULHRW, PMVNZB, PMVLZB, PMVGEZB, PMULHRIW, PMACHRIW

3DNow! instructions[edit]

Added with K6-2[edit]

FEMMS, PAVGUSB, PF2ID, PFACC, PFADD, PFCMPEQ, PFCMPGE, PFCMPGT, PFMAX, PFMIN, PFMUL, PFRCP, PFRCPIT1, PFRCPIT2, PFRSQIT1, PFRSQRT, PFSUB, PFSUBR, PI2FD, PMULHRW, PREFETCH, PREFETCHW

3DNow!+ instructions[edit]

Added with Athlon and K6-2+[edit]

PF2IW, PFNACC, PFPNACC, PI2FW, PSWAPD

Added with Geode GX[edit]

PFRSQRTV, PFRCPV

SSE instructions[edit]

Added with Pentium III

SSE SIMD floating-point instructions[edit]

ADDPS, ADDSS, CMPPS, CMPSS, COMISS, CVTPI2PS, CVTPS2PI, CVTSI2SS, CVTSS2SI, CVTTPS2PI, CVTTSS2SI, DIVPS, DIVSS, LDMXCSR, MAXPS, MAXSS, MINPS, MINSS, MOVAPS, MOVHLPS, MOVHPS, MOVLHPS, MOVLPS, MOVMSKPS, MOVNTPS, MOVSS, MOVUPS, MULPS, MULSS, RCPPS, RCPSS, RSQRTPS, RSQRTSS, SHUFPS, SQRTPS, SQRTSS, STMXCSR, SUBPS, SUBSS, UCOMISS, UNPCKHPS, UNPCKLPS

SSE SIMD integer instructions[edit]

ANDNPS, ANDPS, ORPS, PAVGB, PAVGW, PEXTRW, PINSRW, PMAXSW, PMAXUB, PMINSW, PMINUB, PMOVMSKB, PMULHUW, PSADBW, PSHUFW, XORPS

Instruction Opcode Meaning
MOVUPS xmm1, xmm2/m128 0F 10 /r Move Unaligned Packed Single-Precision Floating-Point Values
MOVSS xmm1, xmm2/m32 F3 0F 10 /r Move Scalar Single-Precision Floating-Point Values
MOVUPS xmm2/m128, xmm1 0F 11 /r Move Unaligned Packed Single-Precision Floating-Point Values
MOVSS xmm2/m32, xmm1 F3 0F 11 /r Move Scalar Single-Precision Floating-Point Values
MOVLPS xmm, m64 0F 12 /r Move Low Packed Single-Precision Floating-Point Values
MOVHLPS xmm1, xmm2 0F 12 /r Move Packed Single-Precision Floating-Point Values High to Low
MOVLPS m64, xmm 0F 13 /r Move Low Packed Single-Precision Floating-Point Values
UNPCKLPS xmm1, xmm2/m128 0F 14 /r Unpack and Interleave Low Packed Single-Precision Floating-Point Values
UNPCKHPS xmm1, xmm2/m128 0F 15 /r Unpack and Interleave High Packed Single-Precision Floating-Point Values
MOVHPS xmm, m64 0F 16 /r Move High Packed Single-Precision Floating-Point Values
MOVLHPS xmm1, xmm2 0F 16 /r Move Packed Single-Precision Floating-Point Values Low to High
MOVHPS m64, xmm 0F 17 /r Move High Packed Single-Precision Floating-Point Values
PREFETCHNTA 0F 18 /0 Prefetch Data Into Caches (non-temporal data with respect to all cache levels)
PREFETCHT0 0F 18 /1 Prefetch Data Into Caches (temporal data)
PREFETCHT1 0F 18 /2 Prefetch Data Into Caches (temporal data with respect to first level cache)
PREFETCHT2 0F 18 /3 Prefetch Data Into Caches (temporal data with respect to second level cache)
NOP 0F 1F /0 No Operation
MOVAPS xmm1, xmm2/m128 0F 28 /r Move Aligned Packed Single-Precision Floating-Point Values
MOVAPS xmm2/m128, xmm1 0F 29 /r Move Aligned Packed Single-Precision Floating-Point Values
CVTPI2PS xmm, mm/m64 0F 2A /r Convert Packed Dword Integers to Packed Single-Precision FP Values
CVTSI2SS xmm, r/m32 F3 0F 2A /r Convert Dword Integer to Scalar Single-Precision FP Value
MOVNTPS m128, xmm 0F 2B /r Store Packed Single-Precision Floating-Point Values Using Non-Temporal Hint
CVTTPS2PI mm, xmm/m64 0F 2C /r Convert with Truncation Packed Single-Precision FP Values to Packed Dword Integers
CVTTSS2SI r32, xmm/m32 F3 0F 2C /r Convert with Truncation Scalar Single-Precision FP Value to Dword Integer
CVTPS2PI mm, xmm/m64 0F 2D /r Convert Packed Single-Precision FP Values to Packed Dword Integers
CVTSS2SI r32, xmm/m32 F3 0F 2D /r Convert Scalar Single-Precision FP Value to Dword Integer
UCOMISS xmm1, xmm2/m32 0F 2E /r Unordered Compare Scalar Single-Precision Floating-Point Values and Set EFLAGS
COMISS xmm1, xmm2/m32 0F 2F /r Compare Scalar Ordered Single-Precision Floating-Point Values and Set EFLAGS
SQRTPS xmm1, xmm2/m128 0F 51 /r Compute Square Roots of Packed Single-Precision Floating-Point Values
SQRTSS xmm1, xmm2/m32 F3 0F 51 /r Compute Square Root of Scalar Single-Precision Floating-Point Value
RSQRTPS xmm1, xmm2/m128 0F 52 /r Compute Reciprocal of Square Root of Packed Single-Precision Floating-Point Value
RSQRTSS xmm1, xmm2/m32 F3 0F 52 /r Compute Reciprocal of Square Root of Scalar Single-Precision Floating-Point Value
RCPPS xmm1, xmm2/m128 0F 53 /r Compute Reciprocal of Packed Single-Precision Floating-Point Values
RCPSS xmm1, xmm2/m32 F3 0F 53 /r Compute Reciprocal of Scalar Single-Precision Floating-Point Values
ANDPS xmm1, xmm2/m128 0F 54 /r Bitwise Logical AND of Packed Single-Precision Floating-Point Values
ANDNPS xmm1, xmm2/m128 0F 55 /r Bitwise Logical AND NOT of Packed Single-Precision Floating-Point Values
ORPS xmm1, xmm2/m128 0F 56 /r Bitwise Logical OR of Single-Precision Floating-Point Values
XORPS xmm1, xmm2/m128 0F 57 /r Bitwise Logical XOR for Single-Precision Floating-Point Values
ADDPS xmm1, xmm2/m128 0F 58 /r Add Packed Single-Precision Floating-Point Values
ADDSS xmm1, xmm2/m32 F3 0F 58 /r Add Scalar Single-Precision Floating-Point Values
MULPS xmm1, xmm2/m128 0F 59 /r Multiply Packed Single-Precision Floating-Point Values
MULSS xmm1, xmm2/m32 F3 0F 59 /r Multiply Scalar Single-Precision Floating-Point Values
SUBPS xmm1, xmm2/m128 0F 5C /r Subtract Packed Single-Precision Floating-Point Values
SUBSS xmm1, xmm2/m32 F3 0F 5C /r Subtract Scalar Single-Precision Floating-Point Values
MINPS xmm1, xmm2/m128 0F 5D /r Return Minimum Packed Single-Precision Floating-Point Values
MINSS xmm1, xmm2/m32 F3 0F 5D /r Return Minimum Scalar Single-Precision Floating-Point Values
DIVPS xmm1, xmm2/m128 0F 5E /r Divide Packed Single-Precision Floating-Point Values
DIVSS xmm1, xmm2/m32 F3 0F 5E /r Divide Scalar Single-Precision Floating-Point Values
MAXPS xmm1, xmm2/m128 0F 5F /r Return Maximum Packed Single-Precision Floating-Point Values
MAXSS xmm1, xmm2/m32 F3 0F 5F /r Return Maximum Scalar Single-Precision Floating-Point Values
PSHUFW mm1, mm2/m64, imm8 0F 70 /r ib Shuffle Packed Words
LDMXCSR m32 0F AE /2 Load MXCSR Register State
STMXCSR m32 0F AE /3 Store MXCSR Register State
SFENCE 0F AE /7 Store Fence
CMPPS xmm1, xmm2/m128, imm8 0F C2 /r ib Compare Packed Single-Precision Floating-Point Values
CMPSS xmm1, xmm2/m32, imm8 F3 0F C2 /r ib Compare Scalar Single-Precision Floating-Point Values
PINSRW mm, r32/m16, imm8 0F C4 /r Insert Word
PEXTRW r32, mm, imm8 0F C5 /r Extract Word
SHUFPS xmm1, xmm2/m128, imm8 0F C6 /r ib Shuffle Packed Single-Precision Floating-Point Values
PMOVMSKB r32, mm 0F D7 /r Move Byte Mask
PMINUB mm1, mm2/m64 0F DA /r Minimum of Packed Unsigned Byte Integers
PMAXUB mm1, mm2/m64 0F DE /r Maximum of Packed Unsigned Byte Integers
PAVGB mm1, mm2/m64 0F E0 /r Average Packed Integers
PAVGW mm1, mm2/m64 0F E3 /r Average Packed Integers
PMULHUW mm1, mm2/m64 0F E4 /r Multiply Packed Unsigned Integers and Store High Result
MOVNTQ m64, mm 0F E7 /r Store of Quadword Using Non-Temporal Hint
PMINSW mm1, mm2/m64 0F EA /r Minimum of Packed Signed Word Integers
PMAXSW mm1, mm2/m64 0F EE /r Maximum of Packed Signed Word Integers
PSADBW mm1, mm2/m64 0F F6 /r Compute Sum of Absolute Differences
MASKMOVQ mm1, mm2 0F F7 /r Store Selected Bytes of Quadword

SSE2 instructions[edit]

Added with Pentium 4 Also see integer instructions added with Pentium 4

SSE2 SIMD floating-point instructions[edit]

Instruction Opcode Meaning
ADDPD xmm1, xmm2/m128 66 0F 58 /r Add Packed Double-Precision Floating-Point Values
ADDSD xmm1, xmm2/m64 F2 0F 58 /r Add Low Double-Precision Floating-Point Value
ANDNPD xmm1, xmm2/m128 66 0F 55 /r Bitwise Logical AND NOT
CMPPD xmm1, xmm2/m128, imm8 66 0F C2 /r ib Compare Packed Double-Precision Floating-Point Values
CMPSD xmm1, xmm2/m64, imm8 F2 0F C2 /r ib Compare Low Double-Precision Floating-Point Values

ADDPD, ADDSD, ANDNPD, ANDPD, CMPPD, CMPSD*, COMISD, CVTDQ2PD, CVTDQ2PS, CVTPD2DQ, CVTPD2PI, CVTPD2PS, CVTPI2PD, CVTPS2DQ, CVTPS2PD, CVTSD2SI, CVTSD2SS, CVTSI2SD, CVTSS2SD, CVTTPD2DQ, CVTTPD2PI, CVTTPS2DQ, CVTTSD2SI, DIVPD, DIVSD, MAXPD, MAXSD, MINPD, MINSD, MOVAPD, MOVHPD, MOVLPD, MOVMSKPD, MOVSD*, MOVUPD, MULPD, MULSD, ORPD, SHUFPD, SQRTPD, SQRTSD, SUBPD, SUBSD, UCOMISD, UNPCKHPD, UNPCKLPD, XORPD

SSE2 SIMD integer instructions[edit]

MOVDQ2Q, MOVDQA, MOVDQU, MOVQ2DQ, PADDQ, PSUBQ, PMULUDQ, PSHUFHW, PSHUFLW, PSHUFD, PSLLDQ, PSRLDQ, PUNPCKHQDQ, PUNPCKLQDQ

SSE3 instructions[edit]

Added with Pentium 4 supporting SSE3 Also see integer and floating-point instructions added with Pentium 4 SSE3

SSE3 SIMD floating-point instructions[edit]

  • ADDSUBPD, ADDSUBPS (for Complex Arithmetic)
  • HADDPD, HADDPS, HSUBPD, HSUBPS (for Graphics)
  • MOVDDUP, MOVSHDUP, MOVSLDUP (for Complex Arithmetic)

SSSE3 instructions[edit]

Added with Xeon 5100 series and initial Core 2

  • PSIGNW, PSIGND, PSIGNB
  • PSHUFB
  • PMULHRSW, PMADDUBSW
  • PHSUBW, PHSUBSW, PHSUBD
  • PHADDW, PHADDSW, PHADDD
  • PALIGNR
  • PABSW, PABSD, PABSB

SSE4 instructions[edit]

SSE4.1[edit]

Added with Core 2 manufactured in 45nm

  • MPSADBW
  • PHMINPOSUW
  • PMULLD, PMULDQ
  • DPPS, DPPD
  • BLENDPS, BLENDPD, BLENDVPS, BLENDVPD, PBLENDVB, PBLENDW
  • PMINSB, PMAXSB, PMINUW, PMAXUW, PMINUD, PMAXUD, PMINSD, PMAXSD
  • ROUNDPS, ROUNDSS, ROUNDPD, ROUNDSD
  • INSERTPS, PINSRB, PINSRD/PINSRQ, EXTRACTPS, PEXTRB, PEXTRW, PEXTRD/PEXTRQ
  • PMOVSXBW, PMOVZXBW, PMOVSXBD, PMOVZXBD, PMOVSXBQ, PMOVZXBQ, PMOVSXWD, PMOVZXWD, PMOVSXWQ, PMOVZXWQ, PMOVSXDQ, PMOVZXDQ
  • PTEST
  • PCMPEQQ
  • PACKUSDW
  • MOVNTDQA

SSE4a[edit]

Added with Phenom processors

  • LZCNT, POPCNT (POPulation CouNT) - advanced bit manipulation
  • EXTRQ/INSERTQ
  • MOVNTSD/MOVNTSS

SSE4.2[edit]

Added with Nehalem processors

  • CRC32
  • PCMPESTRI
  • PCMPESTRM
  • PCMPISTRI
  • PCMPISTRM
  • PCMPGTQ

FMA instructions[edit]

Instruction Opcode Meaning Notes
VFMADDPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 69 /r /is4 Fused Multiply-Add of Packed Double-Precision Floating-Point Values
VFMADDPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 68 /r /is4 Fused Multiply-Add of Packed Single-Precision Floating-Point Values
VFMADDSD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6B /r /is4 Fused Multiply-Add of Scalar Double-Precision Floating-Point Values
VFMADDSS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6A /r /is4 Fused Multiply-Add of Scalar Single-Precision Floating-Point Values
VFMADDSUBPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 5D /r /is4 Fused Multiply-Alternating Add/Subtract of Packed Double-Precision Floating-Point Values
VFMADDSUBPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 5C /r /is4 Fused Multiply-Alternating Add/Subtract of Packed Single-Precision Floating-Point Values
VFMSUBADDPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 5F /r /is4 Fused Multiply-Alternating Subtract/Add of Packed Double-Precision Floating-Point Values
VFMSUBADDPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 5E /r /is4 Fused Multiply-Alternating Subtract/Add of Packed Single-Precision Floating-Point Values
VFMSUBPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6D /r /is4 Fused Multiply-Subtract of Packed Double-Precision Floating-Point Values
VFMSUBPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6C /r /is4 Fused Multiply-Subtract of Packed Single-Precision Floating-Point Values
VFMSUBSD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6F /r /is4 Fused Multiply-Subtract of Scalar Double-Precision Floating-Point Values
VFMSUBSS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 6E /r /is4 Fused Multiply-Subtract of Scalar Single-Precision Floating-Point Values
VFNMADDPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 79 /r /is4 Fused Negative Multiply-Add of Packed Double-Precision Floating-Point Values
VFNMADDPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 78 /r /is4 Fused Negative Multiply-Add of Packed Single-Precision Floating-Point Values
VFNMADDSD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7B /r /is4 Fused Negative Multiply-Add of Scalar Double-Precision Floating-Point Values
VFNMADDSS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7A /r /is4 Fused Negative Multiply-Add of Scalar Single-Precision Floating-Point Values
VFNMSUBPD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7D /r /is4 Fused Negative Multiply-Subtract of Packed Double-Precision Floating-Point Values
VFNMSUBPS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7C /r /is4 Fused Negative Multiply-Subtract of Packed Single-Precision Floating-Point Values
VFNMSUBSD xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7F /r /is4 Fused Negative Multiply-Subtract of Scalar Double-Precision Floating-Point Values
VFNMSUBSS xmm0, xmm1, xmm2, xmm3 C4E3 WvvvvL01 7E /r /is4 Fused Negative Multiply-Subtract of Scalar Single-Precision Floating-Point Values

Intel AES instructions[edit]

Main article: AES instruction set

6 new instructions.

Instruction Description
AESENC Perform one round of an AES encryption flow
AESENCLAST Perform the last round of an AES encryption flow
AESDEC Perform one round of an AES decryption flow
AESDECLAST Perform the last round of an AES decryption flow
AESKEYGENASSIST Assist in AES round key generation
AESIMC Assist in AES Inverse Mix Columns

Undocumented instructions[edit]

The x86 CPUs contain undocumented instructions which are implemented on the chips but not listed in some official documents. They can be found in various sources across the Internet, such as Ralf Brown's Interrupt List and at http://sandpile.org.

Mnemonic Opcode Description Status
AAM imm8 D4 imm8 Divide AL by imm8, put the quotient in AH, and the remainder in AL Available beginning with 8086, documented since Pentium (earlier documentation lists no arguments)
AAD imm8 D5 imm8 Multiplication counterpart of AAM Available beginning with 8086, documented since Pentium (earlier documentation lists no arguments)
SALC D6 Set AL depending on the value of the Carry Flag (a 1-byte alternative of SBB AL, AL) Available beginning with 8086, but only documented since Pentium Pro.
UD1 0F B9 Intentionally undefined instruction, but unlike UD2 this was not published
ICEBP F1 Single byte single-step exception / Invoke ICE Available beginning with 80386, documented (as INT1) since Pentium Pro
LOADALL 0F 05 Loads All Registers from Memory Address 0x000800H Only available on 80286
Unknown mnemonic 0F 04 Exact purpose unknown, causes CPU hang. (the only way out is CPU reset)[2]

In some implementations, emulated through BIOS as a halting sequence.[3]

Only available on 80286
LOADALLD 0F 07 Loads All Registers from Memory Address ES:EDI Only available on 80386

See also[edit]

References[edit]

External links[edit]