# HADDPD

# Packed Double-FP Horizontal Add

Opcode Mnemonic Description
66 0F 7C /r HADDPD xmm1, xmm2/m128 Add horizontally packed DP FP numbers from xmm2/m128 to xmm1.

# 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.

# Operation

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

1
2
3

# 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.

# Numeric Exceptions

Overflow, Underflow, Invalid, Precision, Denormal.

# Protected Mode Exceptions

#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.
#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.
#SS(0) For an illegal address in the SS segment.
#PF(fault-code) For a page fault.
#NM If TS bit in CR0 is set.
#XM For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT = 1).

# Real-Address Mode Exceptions

#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.
#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.
#NM If TS bit in CR0 is set.
#XM For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT = 1).

# Virtual-8086 Mode Exceptions

#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.
#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.
#NM If TS bit in CR0 is set.
#XM For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT = 1).
#UD If CR0.EM = 1. For an unmasked Streaming SIMD Extensions numeric exception (CR4.OSXMMEXCPT = 0). If CR4.OSFXSR(bit 9) = 0. If CPUID.SSE3(ECX bit 0) = 0.
Instruction Latency Throughput Execution Unit
CPUID 0F3n 0F3n 0F3n
HADDPD 13 4 FP_ADD FP_MISC