>
<th>Opcode/Instruction</th>
<th>Op/En</th>
<th>64/32-bit Mode</th>
<th>CPUID Feature Flag</th>
<th>Description</th></tr>
<tr>
<td>66 0F 7C /<em>r</em> HADDPD <em>xmm1, xmm2/m128</em></td>
<td>RM</td>
<td>V/V</td>
<td>SSE3</td>
<td>Horizontal add packed double-precision floating-point values from <em>xmm2/m128</em> to <em>xmm1</em>.</td></tr>
<tr>
<td>VEX.NDS.128.66.0F.WIG 7C /r VHADDPD xmm1,xmm2, xmm3/m128</td>
<td>RVM</td>
<td>V/V</td>
<td>AVX</td>
<td>Horizontal add packed double-precision floating-poin