HADDPD

Packed Double-FP Horizontal Add

Opcodes

Hex Mnemonic Encoding Long Mode Legacy Mode Description
66 0F 7C /r HADDPD xmm1, xmm2/m128 A Valid Valid Horizontal add packed double-precision floating-point values from xmm2/m128 to xmm1.

Instruction Operand Encoding

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

Description

Adds the double-precision floating-point values in the high and low quadwords of the destination operand and stores the result in the low quadword of the destination operand.

Adds the double-precision floating-point values in the high and low quadwords of the source operand and stores the result in the high quadword of the destination operand.

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

Pseudo Code

xmm1[63:0] = xmm1[63:0] + xmm1[127:64];
xmm1[127:64] = xmm2/m128[63:0] + xmm2/m128[127:64];

Exceptions

Numeric Exceptions

Overflow, Underflow, Invalid, Precision, Denormal.

Exceptions

When the source operand is a memory operand, the operand must be aligned on a 16-byte boundary or a general-protection exception (#GP) will be generated.

64-Bit Mode Exceptions

Exception Description
#UD If an unmasked SIMD floating-point exception and CR4.OSXMMEXCPT[bit 10] = 0. If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID feature flag SSE3 is 0. If the LOCK prefix is used.
#XM If an unmasked SIMD floating-point exception and CR4.OSXM MEXCPT[bit 10] = 1.
#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. If memory operand is not aligned on a 16-byte boundary, regardless of segment.
#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
#PF(fault-code) For a page fault.
#UD If CR0.EM[bit 2] = 1. For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT[bit 10] = 0). If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#XM For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT[bit 10] = 1).
#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. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.

Real-Address Mode Exceptions

Exception Description
#UD If CR0.EM[bit 2] = 1. For an unmasked Streaming SIMD Extensions numeric excep tion (CR4.OSXMMEXCPT[bit 10] = 0). If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#XM For an unmasked Streaming SIMD Extensions numeric excep tion (CR4.OSXMMEXCPT[bit 10] = 1).
#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. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.

Protected Mode Exceptions

Exception Description
#UD If CR0.EM[bit 2] = 1. For an unmasked Streaming SIMD Extensions numeric excep tion (CR4.OSXMMEXCPT[bit 10] = 0). If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:ECX.SSE3[bit 0] = 0. If the LOCK prefix is used.
#XM For an unmasked Streaming SIMD Extensions numeric excep tion (CR4.OSXMMEXCPT[bit 10] = 1).
#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. If a memory operand is not aligned on a 16-byte boundary, regardless of segment.