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| <title>FISTTP—Store Integer with Truncation </title></head> |
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| <h1>FISTTP—Store Integer with Truncation</h1> |
| <table> |
| <tr> |
| <th>Opcode</th> |
| <th>Instruction</th> |
| <th>64-Bit Mode</th> |
| <th>Compat/Leg Mode</th> |
| <th>Description</th></tr> |
| <tr> |
| <td>DF /1</td> |
| <td>FISTTP <em>m16int</em></td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>Store ST(0) in <em>m16int with truncation.</em></td></tr> |
| <tr> |
| <td>DB /1</td> |
| <td>FISTTP <em>m32int</em></td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>Store ST(0) in <em>m32int with truncation.</em></td></tr> |
| <tr> |
| <td>DD /1</td> |
| <td>FISTTP <em>m64int</em></td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>Store ST(0) in <em>m64int</em> with truncation.</td></tr></table> |
| <h2>Description</h2> |
| <p>FISTTP converts the value in ST into a signed integer using truncation (chop) as rounding mode, transfers the result to the destination, and pop ST. FISTTP accepts word, short integer, and long integer destinations.</p> |
| <p>The following table shows the results obtained when storing various classes of numbers in integer format.</p> |
| <h3>Table 3-38. FISTTP Results</h3> |
| <table> |
| <tr> |
| <th>ST(0)</th> |
| <th>DEST</th></tr> |
| <tr> |
| <td>− ∞ or Value Too Large for DEST Format</td> |
| <td>*</td></tr> |
| <tr> |
| <td>F ≤ − 1</td> |
| <td>− I</td></tr> |
| <tr> |
| <td>− 1 < F < + 1</td> |
| <td>0</td></tr> |
| <tr> |
| <td>F Š + 1</td> |
| <td>+ I</td></tr> |
| <tr> |
| <td>+ ∞ or Value Too Large for DEST Format</td> |
| <td>*</td></tr> |
| <tr> |
| <td>NaN</td> |
| <td>*</td></tr></table> |
| <p><strong>NOTES:</strong></p> |
| <p>F Means finite floating-point value.</p> |
| <p>Ι</p> |
| <p>Means integer.</p> |
| <p>∗ Indicates floating-point invalid-operation (#IA) exception.</p> |
| <p>This instruction’s operation is the same in non-64-bit modes and 64-bit mode.</p> |
| <h2>Operation</h2> |
| <pre>DEST ← ST; |
| pop ST;</pre> |
| <h2>Flags Affected</h2> |
| <p>C1 is cleared; C0, C2, C3 undefined.</p> |
| <h2>Numeric Exceptions</h2> |
| <p>Invalid, Stack Invalid (stack underflow), Precision.</p> |
| <h2>Protected Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#GP(0)</td> |
| <td> |
| <p>If the destination is in a nonwritable segment.</p> |
| <p>For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.</p></td></tr> |
| <tr> |
| <td>#SS(0)</td> |
| <td>For an illegal address in the SS segment.</td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>For a page fault.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td>If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.</td></tr> |
| <tr> |
| <td>#NM</td> |
| <td> |
| <p>If CR0.EM[bit 2] = 1.</p> |
| <p>If CR0.TS[bit 3] = 1.</p></td></tr> |
| <tr> |
| <td>#UD</td> |
| <td> |
| <p>If CPUID.01H:ECX.SSE3[bit 0] = 0.</p> |
| <p>If the LOCK prefix is used.</p></td></tr></table> |
| <h2>Real Address Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>GP(0)</td> |
| <td>If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.</td></tr> |
| <tr> |
| <td>#NM</td> |
| <td> |
| <p>If CR0.EM[bit 2] = 1.</p> |
| <p>If CR0.TS[bit 3] = 1.</p></td></tr> |
| <tr> |
| <td>#UD</td> |
| <td> |
| <p>If CPUID.01H:ECX.SSE3[bit 0] = 0.</p> |
| <p>If the LOCK prefix is used.</p></td></tr></table> |
| <h2>Virtual 8086 Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>GP(0)</td> |
| <td>If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.</td></tr> |
| <tr> |
| <td>#NM</td> |
| <td> |
| <p>If CR0.EM[bit 2] = 1.</p> |
| <p>If CR0.TS[bit 3] = 1.</p></td></tr> |
| <tr> |
| <td>#UD</td> |
| <td> |
| <p>If CPUID.01H:ECX.SSE3[bit 0] = 0.</p> |
| <p>If the LOCK prefix is used.</p></td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>For a page fault.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td>For unaligned memory reference if the current privilege is 3.</td></tr></table> |
| <h2>Compatibility Mode Exceptions</h2> |
| <p>Same exceptions as in protected mode.</p> |
| <h2>64-Bit Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#SS(0)</td> |
| <td>If a memory address referencing the SS segment is in a non-canonical form.</td></tr> |
| <tr> |
| <td>#GP(0)</td> |
| <td>If the memory address is in a non-canonical form.</td></tr> |
| <tr> |
| <td>#NM</td> |
| <td>CR0.EM[bit 2] or CR0.TS[bit 3] = 1.</td></tr> |
| <tr> |
| <td>#MF</td> |
| <td>If there is a pending x87 FPU exception.</td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>If a page fault occurs.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td> |
| <p>If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.</p> |
| <p>If the LOCK prefix is used.</p></td></tr></table></body></html> |