MOVDDUP

Move One Double-FP and Duplicate

Opcodes

Hex Mnemonic Encoding Long Mode Legacy Mode Description
F2 0F 12 /r MOVDDUP xmm1, xmm2/m64 A Valid Valid Move one double-precision floating-point value from the lower 64-bit operand in xmm2/m64 to xmm1 and duplicate.

Instruction Operand Encoding

Op/En Operand 0 Operand 1 Operand 2 Operand 3
A NA NA ModRM:r/m (r) ModRM:reg (w)

Description

The linear address corresponds to the address of the least-significant byte of the referenced memory data. When a memory address is indicated, the 8 bytes of data at memory location m64 are loaded. When the register-register form of this operation is used, the lower half of the 128-bit source register is duplicated and copied into the 128-bit destination register.

In 64-bit mode, use of the REX.R prefix permits this instruction to access additional registers (XMM8-XMM15).

Pseudo Code

IF (Source = m64)
	(* Load instruction *)
	xmm1[63:0] = m64;
	xmm1[127:64] = m64;
ELSE
	(* Move instruction *)
	xmm1[63:0] = xmm2[63:0];
	xmm1[127:64] = xmm2[63:0];
FI;

Exceptions

Numeric Exceptions

None

64-Bit Mode Exceptions

Exception Description
#AC(0) If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.SSE3(ECX, bit 0) is 0. If the LOCK prefix is used.
#NM If CR0.TS[bit 3] = 1.
#PF(fault-code) For a page fault.
#GP(0) If the memory address is in a non-canonical form.
#SS(0) If a memory address referencing the SS segment is in a non-canonical form.

Compatibility Mode Exceptions

Same exceptions as in protected mode.

Virtual-8086 Mode Exceptions

Exception Description
#AC(0) If alignment checking is enabled and an unaligned memory reference is made.
#PF(fault-code) For a page fault.
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#NM If CR0.TS[bit 3] = 1.
#GP(0) If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.

Real-Address Mode Exceptions

Exception Description
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#NM If CR0.TS[bit 3] = 1.
#GP(0) If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.

Protected Mode Exceptions

Exception Description
#AC(0) If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.
#UD If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#NM If CR0.TS[bit 3] = 1.
#PF(fault-code) For a page fault.
#SS(0) For an illegal address in the SS segment.
#GP(0) For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.