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| <h4 class="subsection">9.21.1 M680x0 Options</h4> |
| |
| <p><a name="index-options_002c-M680x0-1140"></a><a name="index-M680x0-options-1141"></a>The Motorola 680x0 version of <code>as</code> has a few machine |
| dependent options: |
| |
| |
| <a name="index-g_t_0040samp_007b_002dmarch_003d_007d-command-line-option_002c-M680x0-1142"></a> |
| <dl><dt>‘<samp><span class="samp">-march=</span><var>architecture</var></samp>’<dd>This option specifies a target architecture. The following |
| architectures are recognized: |
| <code>68000</code>, |
| <code>68010</code>, |
| <code>68020</code>, |
| <code>68030</code>, |
| <code>68040</code>, |
| <code>68060</code>, |
| <code>cpu32</code>, |
| <code>isaa</code>, |
| <code>isaaplus</code>, |
| <code>isab</code>, |
| <code>isac</code> and |
| <code>cfv4e</code>. |
| |
| <p><a name="index-g_t_0040samp_007b_002dmcpu_003d_007d-command-line-option_002c-M680x0-1143"></a><br><dt>‘<samp><span class="samp">-mcpu=</span><var>cpu</var></samp>’<dd>This option specifies a target cpu. When used in conjunction with the |
| <samp><span class="option">-march</span></samp> option, the cpu must be within the specified |
| architecture. Also, the generic features of the architecture are used |
| for instruction generation, rather than those of the specific chip. |
| |
| <p><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005d68851_007d-command-line-option_002c-M680x0-1144"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005d68881_007d-command-line-option_002c-M680x0-1145"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005ddiv_007d-command-line-option_002c-M680x0-1146"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005dusp_007d-command-line-option_002c-M680x0-1147"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005dfloat_007d-command-line-option_002c-M680x0-1148"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005dmac_007d-command-line-option_002c-M680x0-1149"></a><a name="index-g_t_0040samp_007b_002dm_005bno_002d_005demac_007d-command-line-option_002c-M680x0-1150"></a><br><dt>‘<samp><span class="samp">-m[no-]68851</span></samp>’<dt>‘<samp><span class="samp">-m[no-]68881</span></samp>’<dt>‘<samp><span class="samp">-m[no-]div</span></samp>’<dt>‘<samp><span class="samp">-m[no-]usp</span></samp>’<dt>‘<samp><span class="samp">-m[no-]float</span></samp>’<dt>‘<samp><span class="samp">-m[no-]mac</span></samp>’<dt>‘<samp><span class="samp">-m[no-]emac</span></samp>’<dd> |
| Enable or disable various architecture specific features. If a chip |
| or architecture by default supports an option (for instance |
| <samp><span class="option">-march=isaaplus</span></samp> includes the <samp><span class="option">-mdiv</span></samp> option), |
| explicitly disabling the option will override the default. |
| |
| <p><a name="index-g_t_0040samp_007b_002dl_007d-option_002c-M680x0-1151"></a><br><dt>‘<samp><span class="samp">-l</span></samp>’<dd>You can use the ‘<samp><span class="samp">-l</span></samp>’ option to shorten the size of references to undefined |
| symbols. If you do not use the ‘<samp><span class="samp">-l</span></samp>’ option, references to undefined |
| symbols are wide enough for a full <code>long</code> (32 bits). (Since |
| <code>as</code> cannot know where these symbols end up, <code>as</code> can |
| only allocate space for the linker to fill in later. Since <code>as</code> |
| does not know how far away these symbols are, it allocates as much space as it |
| can.) If you use this option, the references are only one word wide (16 bits). |
| This may be useful if you want the object file to be as small as possible, and |
| you know that the relevant symbols are always less than 17 bits away. |
| |
| <p><a name="index-g_t_0040samp_007b_002d_002dregister_002dprefix_002doptional_007d-option_002c-M680x0-1152"></a><br><dt>‘<samp><span class="samp">--register-prefix-optional</span></samp>’<dd>For some configurations, especially those where the compiler normally |
| does not prepend an underscore to the names of user variables, the |
| assembler requires a ‘<samp><span class="samp">%</span></samp>’ before any use of a register name. This |
| is intended to let the assembler distinguish between C variables and |
| functions named ‘<samp><span class="samp">a0</span></samp>’ through ‘<samp><span class="samp">a7</span></samp>’, and so on. The ‘<samp><span class="samp">%</span></samp>’ is |
| always accepted, but is not required for certain configurations, notably |
| ‘<samp><span class="samp">sun3</span></samp>’. The ‘<samp><span class="samp">--register-prefix-optional</span></samp>’ option may be used |
| to permit omitting the ‘<samp><span class="samp">%</span></samp>’ even for configurations for which it is |
| normally required. If this is done, it will generally be impossible to |
| refer to C variables and functions with the same names as register |
| names. |
| |
| <p><a name="index-g_t_0040samp_007b_002d_002dbitwise_002dor_007d-option_002c-M680x0-1153"></a><br><dt>‘<samp><span class="samp">--bitwise-or</span></samp>’<dd>Normally the character ‘<samp><span class="samp">|</span></samp>’ is treated as a comment character, which |
| means that it can not be used in expressions. The ‘<samp><span class="samp">--bitwise-or</span></samp>’ |
| option turns ‘<samp><span class="samp">|</span></samp>’ into a normal character. In this mode, you must |
| either use C style comments, or start comments with a ‘<samp><span class="samp">#</span></samp>’ character |
| at the beginning of a line. |
| |
| <p><a name="index-g_t_0040samp_007b_002d_002dbase_002dsize_002ddefault_002d16_007d-1154"></a><a name="index-g_t_0040samp_007b_002d_002dbase_002dsize_002ddefault_002d32_007d-1155"></a><br><dt>‘<samp><span class="samp">--base-size-default-16 --base-size-default-32</span></samp>’<dd>If you use an addressing mode with a base register without specifying |
| the size, <code>as</code> will normally use the full 32 bit value. |
| For example, the addressing mode ‘<samp><span class="samp">%a0@(%d0)</span></samp>’ is equivalent to |
| ‘<samp><span class="samp">%a0@(%d0:l)</span></samp>’. You may use the ‘<samp><span class="samp">--base-size-default-16</span></samp>’ |
| option to tell <code>as</code> to default to using the 16 bit value. |
| In this case, ‘<samp><span class="samp">%a0@(%d0)</span></samp>’ is equivalent to ‘<samp><span class="samp">%a0@(%d0:w)</span></samp>’. |
| You may use the ‘<samp><span class="samp">--base-size-default-32</span></samp>’ option to restore the |
| default behaviour. |
| |
| <p><a name="index-g_t_0040samp_007b_002d_002ddisp_002dsize_002ddefault_002d16_007d-1156"></a><a name="index-g_t_0040samp_007b_002d_002ddisp_002dsize_002ddefault_002d32_007d-1157"></a><br><dt>‘<samp><span class="samp">--disp-size-default-16 --disp-size-default-32</span></samp>’<dd>If you use an addressing mode with a displacement, and the value of the |
| displacement is not known, <code>as</code> will normally assume that |
| the value is 32 bits. For example, if the symbol ‘<samp><span class="samp">disp</span></samp>’ has not |
| been defined, <code>as</code> will assemble the addressing mode |
| ‘<samp><span class="samp">%a0@(disp,%d0)</span></samp>’ as though ‘<samp><span class="samp">disp</span></samp>’ is a 32 bit value. You may |
| use the ‘<samp><span class="samp">--disp-size-default-16</span></samp>’ option to tell <code>as</code> |
| to instead assume that the displacement is 16 bits. In this case, |
| <code>as</code> will assemble ‘<samp><span class="samp">%a0@(disp,%d0)</span></samp>’ as though |
| ‘<samp><span class="samp">disp</span></samp>’ is a 16 bit value. You may use the |
| ‘<samp><span class="samp">--disp-size-default-32</span></samp>’ option to restore the default behaviour. |
| |
| <p><a name="index-g_t_0040samp_007b_002d_002dpcrel_007d-1158"></a><br><dt>‘<samp><span class="samp">--pcrel</span></samp>’<dd>Always keep branches PC-relative. In the M680x0 architecture all branches |
| are defined as PC-relative. However, on some processors they are limited |
| to word displacements maximum. When <code>as</code> needs a long branch |
| that is not available, it normally emits an absolute jump instead. This |
| option disables this substitution. When this option is given and no long |
| branches are available, only word branches will be emitted. An error |
| message will be generated if a word branch cannot reach its target. This |
| option has no effect on 68020 and other processors that have long branches. |
| see <a href="M68K_002dBranch.html#M68K_002dBranch">Branch Improvement</a>. |
| |
| <p><a name="index-g_t_0040samp_007b_002dm68000_007d-and-related-options-1159"></a><a name="index-architecture-options_002c-M680x0-1160"></a><a name="index-M680x0-architecture-options-1161"></a><br><dt>‘<samp><span class="samp">-m68000</span></samp>’<dd><code>as</code> can assemble code for several different members of the |
| Motorola 680x0 family. The default depends upon how <code>as</code> |
| was configured when it was built; normally, the default is to assemble |
| code for the 68020 microprocessor. The following options may be used to |
| change the default. These options control which instructions and |
| addressing modes are permitted. The members of the 680x0 family are |
| very similar. For detailed information about the differences, see the |
| Motorola manuals. |
| |
| <dl> |
| <dt>‘<samp><span class="samp">-m68000</span></samp>’<dt>‘<samp><span class="samp">-m68ec000</span></samp>’<dt>‘<samp><span class="samp">-m68hc000</span></samp>’<dt>‘<samp><span class="samp">-m68hc001</span></samp>’<dt>‘<samp><span class="samp">-m68008</span></samp>’<dt>‘<samp><span class="samp">-m68302</span></samp>’<dt>‘<samp><span class="samp">-m68306</span></samp>’<dt>‘<samp><span class="samp">-m68307</span></samp>’<dt>‘<samp><span class="samp">-m68322</span></samp>’<dt>‘<samp><span class="samp">-m68356</span></samp>’<dd>Assemble for the 68000. ‘<samp><span class="samp">-m68008</span></samp>’, ‘<samp><span class="samp">-m68302</span></samp>’, and so on are synonyms |
| for ‘<samp><span class="samp">-m68000</span></samp>’, since the chips are the same from the point of view |
| of the assembler. |
| |
| <br><dt>‘<samp><span class="samp">-m68010</span></samp>’<dd>Assemble for the 68010. |
| |
| <br><dt>‘<samp><span class="samp">-m68020</span></samp>’<dt>‘<samp><span class="samp">-m68ec020</span></samp>’<dd>Assemble for the 68020. This is normally the default. |
| |
| <br><dt>‘<samp><span class="samp">-m68030</span></samp>’<dt>‘<samp><span class="samp">-m68ec030</span></samp>’<dd>Assemble for the 68030. |
| |
| <br><dt>‘<samp><span class="samp">-m68040</span></samp>’<dt>‘<samp><span class="samp">-m68ec040</span></samp>’<dd>Assemble for the 68040. |
| |
| <br><dt>‘<samp><span class="samp">-m68060</span></samp>’<dt>‘<samp><span class="samp">-m68ec060</span></samp>’<dd>Assemble for the 68060. |
| |
| <br><dt>‘<samp><span class="samp">-mcpu32</span></samp>’<dt>‘<samp><span class="samp">-m68330</span></samp>’<dt>‘<samp><span class="samp">-m68331</span></samp>’<dt>‘<samp><span class="samp">-m68332</span></samp>’<dt>‘<samp><span class="samp">-m68333</span></samp>’<dt>‘<samp><span class="samp">-m68334</span></samp>’<dt>‘<samp><span class="samp">-m68336</span></samp>’<dt>‘<samp><span class="samp">-m68340</span></samp>’<dt>‘<samp><span class="samp">-m68341</span></samp>’<dt>‘<samp><span class="samp">-m68349</span></samp>’<dt>‘<samp><span class="samp">-m68360</span></samp>’<dd>Assemble for the CPU32 family of chips. |
| |
| <br><dt>‘<samp><span class="samp">-m5200</span></samp>’<dt>‘<samp><span class="samp">-m5202</span></samp>’<dt>‘<samp><span class="samp">-m5204</span></samp>’<dt>‘<samp><span class="samp">-m5206</span></samp>’<dt>‘<samp><span class="samp">-m5206e</span></samp>’<dt>‘<samp><span class="samp">-m521x</span></samp>’<dt>‘<samp><span class="samp">-m5249</span></samp>’<dt>‘<samp><span class="samp">-m528x</span></samp>’<dt>‘<samp><span class="samp">-m5307</span></samp>’<dt>‘<samp><span class="samp">-m5407</span></samp>’<dt>‘<samp><span class="samp">-m547x</span></samp>’<dt>‘<samp><span class="samp">-m548x</span></samp>’<dt>‘<samp><span class="samp">-mcfv4</span></samp>’<dt>‘<samp><span class="samp">-mcfv4e</span></samp>’<dd>Assemble for the ColdFire family of chips. |
| |
| <br><dt>‘<samp><span class="samp">-m68881</span></samp>’<dt>‘<samp><span class="samp">-m68882</span></samp>’<dd>Assemble 68881 floating point instructions. This is the default for the |
| 68020, 68030, and the CPU32. The 68040 and 68060 always support |
| floating point instructions. |
| |
| <br><dt>‘<samp><span class="samp">-mno-68881</span></samp>’<dd>Do not assemble 68881 floating point instructions. This is the default |
| for 68000 and the 68010. The 68040 and 68060 always support floating |
| point instructions, even if this option is used. |
| |
| <br><dt>‘<samp><span class="samp">-m68851</span></samp>’<dd>Assemble 68851 MMU instructions. This is the default for the 68020, |
| 68030, and 68060. The 68040 accepts a somewhat different set of MMU |
| instructions; ‘<samp><span class="samp">-m68851</span></samp>’ and ‘<samp><span class="samp">-m68040</span></samp>’ should not be used |
| together. |
| |
| <br><dt>‘<samp><span class="samp">-mno-68851</span></samp>’<dd>Do not assemble 68851 MMU instructions. This is the default for the |
| 68000, 68010, and the CPU32. The 68040 accepts a somewhat different set |
| of MMU instructions. |
| </dl> |
| </dl> |
| |
| </body></html> |
| |
