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| <h4 class="subsection">3.17.26 MMIX Options</h4> |
| |
| <p><a name="index-MMIX-Options-1676"></a> |
| These options are defined for the MMIX: |
| |
| <dl> |
| <dt><code>-mlibfuncs</code><dt><code>-mno-libfuncs</code><dd><a name="index-mlibfuncs-1677"></a><a name="index-mno_002dlibfuncs-1678"></a>Specify that intrinsic library functions are being compiled, passing all |
| values in registers, no matter the size. |
| |
| <br><dt><code>-mepsilon</code><dt><code>-mno-epsilon</code><dd><a name="index-mepsilon-1679"></a><a name="index-mno_002depsilon-1680"></a>Generate floating-point comparison instructions that compare with respect |
| to the <code>rE</code> epsilon register. |
| |
| <br><dt><code>-mabi=mmixware</code><dt><code>-mabi=gnu</code><dd><a name="index-mabi_003dmmixware-1681"></a><a name="index-mabi_003dgnu-1682"></a>Generate code that passes function parameters and return values that (in |
| the called function) are seen as registers <code>$0</code> and up, as opposed to |
| the GNU ABI which uses global registers <code>$231</code> and up. |
| |
| <br><dt><code>-mzero-extend</code><dt><code>-mno-zero-extend</code><dd><a name="index-mzero_002dextend-1683"></a><a name="index-mno_002dzero_002dextend-1684"></a>When reading data from memory in sizes shorter than 64 bits, use (do not |
| use) zero-extending load instructions by default, rather than |
| sign-extending ones. |
| |
| <br><dt><code>-mknuthdiv</code><dt><code>-mno-knuthdiv</code><dd><a name="index-mknuthdiv-1685"></a><a name="index-mno_002dknuthdiv-1686"></a>Make the result of a division yielding a remainder have the same sign as |
| the divisor. With the default, <samp><span class="option">-mno-knuthdiv</span></samp>, the sign of the |
| remainder follows the sign of the dividend. Both methods are |
| arithmetically valid, the latter being almost exclusively used. |
| |
| <br><dt><code>-mtoplevel-symbols</code><dt><code>-mno-toplevel-symbols</code><dd><a name="index-mtoplevel_002dsymbols-1687"></a><a name="index-mno_002dtoplevel_002dsymbols-1688"></a>Prepend (do not prepend) a ‘<samp><span class="samp">:</span></samp>’ to all global symbols, so the assembly |
| code can be used with the <code>PREFIX</code> assembly directive. |
| |
| <br><dt><code>-melf</code><dd><a name="index-melf-1689"></a>Generate an executable in the ELF format, rather than the default |
| ‘<samp><span class="samp">mmo</span></samp>’ format used by the <samp><span class="command">mmix</span></samp> simulator. |
| |
| <br><dt><code>-mbranch-predict</code><dt><code>-mno-branch-predict</code><dd><a name="index-mbranch_002dpredict-1690"></a><a name="index-mno_002dbranch_002dpredict-1691"></a>Use (do not use) the probable-branch instructions, when static branch |
| prediction indicates a probable branch. |
| |
| <br><dt><code>-mbase-addresses</code><dt><code>-mno-base-addresses</code><dd><a name="index-mbase_002daddresses-1692"></a><a name="index-mno_002dbase_002daddresses-1693"></a>Generate (do not generate) code that uses <em>base addresses</em>. Using a |
| base address automatically generates a request (handled by the assembler |
| and the linker) for a constant to be set up in a global register. The |
| register is used for one or more base address requests within the range 0 |
| to 255 from the value held in the register. The generally leads to short |
| and fast code, but the number of different data items that can be |
| addressed is limited. This means that a program that uses lots of static |
| data may require <samp><span class="option">-mno-base-addresses</span></samp>. |
| |
| <br><dt><code>-msingle-exit</code><dt><code>-mno-single-exit</code><dd><a name="index-msingle_002dexit-1694"></a><a name="index-mno_002dsingle_002dexit-1695"></a>Force (do not force) generated code to have a single exit point in each |
| function. |
| </dl> |
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