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| <title>EXTRACTPS — Extract Packed Single Precision Floating-Point Value </title></head> |
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| <h1>EXTRACTPS — Extract Packed Single Precision Floating-Point Value</h1> |
| <table> |
| <tr> |
| <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> |
| <p>66 0F 3A 17</p> |
| <p>/r ib</p> |
| <p>EXTRACTPS<em> reg/m32, xmm2, imm8</em></p></td> |
| <td>MRI</td> |
| <td>V/V</td> |
| <td>SSE4_1</td> |
| <td>Extract a single-precision floating-point value from <em>xmm2</em> at the source offset specified by <em>imm8 </em>and store the result to <em>reg or m32</em>. The upper 32 bits of r64 is zeroed if reg is r64.</td></tr> |
| <tr> |
| <td> |
| <p>VEX.128.66.0F3A.WIG 17 /r ib</p> |
| <p>VEXTRACTPS r/m32, xmm1, imm8</p></td> |
| <td>MRI</td> |
| <td>V/V</td> |
| <td>AVX</td> |
| <td>Extract one single-precision floating-point value from xmm1 at the offset specified by imm8 and store the result in reg or m32. Zero extend the results in 64-bit register if applicable.</td></tr></table> |
| <h3>Instruction Operand Encoding</h3> |
| <table> |
| <tr> |
| <td>Op/En</td> |
| <td>Operand 1</td> |
| <td>Operand 2</td> |
| <td>Operand 3</td> |
| <td>Operand 4</td></tr> |
| <tr> |
| <td>MRI</td> |
| <td>ModRM:r/m (w)</td> |
| <td>ModRM:reg (r)</td> |
| <td>imm8</td> |
| <td>NA</td></tr></table> |
| <h2>Description</h2> |
| <p>Extracts a single-precision floating-point value from the source operand (second operand) at the 32-bit offset spec-ified from imm8. Immediate bits higher than the most significant offset for the vector length are ignored.</p> |
| <p>The extracted single-precision floating-point value is stored in the low 32-bits of the destination operand</p> |
| <p>In 64-bit mode, destination register operand has default operand size of 64 bits. The upper 32-bits of the register are filled with zero. REX.W is ignored.</p> |
| <p>128-bit Legacy SSE version: When a REX.W prefix is used in 64-bit mode with a general purpose register (GPR) as a destination operand, the packed single quantity is zero extended to 64 bits.</p> |
| <p>VEX.128 encoded version: When VEX.128.66.0F3A.W1 17 form is used in 64-bit mode with a general purpose register (GPR) as a destination operand, the packed single quantity is zero extended to 64 bits. VEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.</p> |
| <p>The source register is an XMM register. Imm8[1:0] determine the starting DWORD offset from which to extract the 32-bit floating-point value.</p> |
| <p>If VEXTRACTPS is encoded with VEX.L= 1, an attempt to execute the instruction encoded with VEX.L= 1 will cause an #UD exception.</p> |
| <h2>Operation</h2> |
| <p><strong>EXTRACTPS (128-bit Legacy SSE version)</strong></p> |
| <pre>SRC_OFFSET ← IMM8[1:0] |
| IF ( 64-Bit Mode and DEST is register) |
| DEST[31:0] ← (SRC[127:0] » (SRC_OFFET*32)) AND 0FFFFFFFFh |
| DEST[63:32] ← 0 |
| ELSE |
| DEST[31:0] ← (SRC[127:0] » (SRC_OFFET*32)) AND 0FFFFFFFFh |
| FI</pre> |
| <p><strong>VEXTRACTPS (VEX.128 encoded version)</strong></p> |
| <pre>SRC_OFFSET ← IMM8[1:0] |
| IF ( 64-Bit Mode and DEST is register) |
| DEST[31:0] ← (SRC[127:0] » (SRC_OFFET*32)) AND 0FFFFFFFFh |
| DEST[63:32] ← 0 |
| ELSE |
| DEST[31:0] ← (SRC[127:0] » (SRC_OFFET*32)) AND 0FFFFFFFFh |
| FI</pre> |
| <h2>Intel C/C++ Compiler Intrinsic Equivalent</h2> |
| <p>EXTRACTPS:</p> |
| <p> _mm_extractmem_ps (float *dest, __m128 a, const int nidx);</p> |
| <p>EXTRACTPS:</p> |
| <p> __m128 _mm_extract_ps (__m128 a, const int nidx);</p> |
| <h2>SIMD Floating-Point Exceptions</h2> |
| <p>None</p> |
| <h2>Other Exceptions</h2> |
| <p>See Exceptions Type 5; additionally</p> |
| <table class="exception-table"> |
| <tr> |
| <td>#UD</td> |
| <td>If VEX.L= 1.</td></tr></table></body></html> |