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<h4 class="subsection">3.17.48 V850 Options</h4>
<p><a name="index-V850-Options-2593"></a>
These ‘<samp><span class="samp">-m</span></samp>’ options are defined for V850 implementations:
<dl>
<dt><code>-mlong-calls</code><dt><code>-mno-long-calls</code><dd><a name="index-mlong_002dcalls-2594"></a><a name="index-mno_002dlong_002dcalls-2595"></a>Treat all calls as being far away (near). If calls are assumed to be
far away, the compiler always loads the function's address into a
register, and calls indirect through the pointer.
<br><dt><code>-mno-ep</code><dt><code>-mep</code><dd><a name="index-mno_002dep-2596"></a><a name="index-mep-2597"></a>Do not optimize (do optimize) basic blocks that use the same index
pointer 4 or more times to copy pointer into the <code>ep</code> register, and
use the shorter <code>sld</code> and <code>sst</code> instructions. The <samp><span class="option">-mep</span></samp>
option is on by default if you optimize.
<br><dt><code>-mno-prolog-function</code><dt><code>-mprolog-function</code><dd><a name="index-mno_002dprolog_002dfunction-2598"></a><a name="index-mprolog_002dfunction-2599"></a>Do not use (do use) external functions to save and restore registers
at the prologue and epilogue of a function. The external functions
are slower, but use less code space if more than one function saves
the same number of registers. The <samp><span class="option">-mprolog-function</span></samp> option
is on by default if you optimize.
<br><dt><code>-mspace</code><dd><a name="index-mspace-2600"></a>Try to make the code as small as possible. At present, this just turns
on the <samp><span class="option">-mep</span></samp> and <samp><span class="option">-mprolog-function</span></samp> options.
<br><dt><code>-mtda=</code><var>n</var><dd><a name="index-mtda-2601"></a>Put static or global variables whose size is <var>n</var> bytes or less into
the tiny data area that register <code>ep</code> points to. The tiny data
area can hold up to 256 bytes in total (128 bytes for byte references).
<br><dt><code>-msda=</code><var>n</var><dd><a name="index-msda-2602"></a>Put static or global variables whose size is <var>n</var> bytes or less into
the small data area that register <code>gp</code> points to. The small data
area can hold up to 64 kilobytes.
<br><dt><code>-mzda=</code><var>n</var><dd><a name="index-mzda-2603"></a>Put static or global variables whose size is <var>n</var> bytes or less into
the first 32 kilobytes of memory.
<br><dt><code>-mv850</code><dd><a name="index-mv850-2604"></a>Specify that the target processor is the V850.
<br><dt><code>-mv850e3v5</code><dd><a name="index-mv850e3v5-2605"></a>Specify that the target processor is the V850E3V5. The preprocessor
constant <code>__v850e3v5__</code> is defined if this option is used.
<br><dt><code>-mv850e2v4</code><dd><a name="index-mv850e2v4-2606"></a>Specify that the target processor is the V850E3V5. This is an alias for
the <samp><span class="option">-mv850e3v5</span></samp> option.
<br><dt><code>-mv850e2v3</code><dd><a name="index-mv850e2v3-2607"></a>Specify that the target processor is the V850E2V3. The preprocessor
constant <code>__v850e2v3__</code> is defined if this option is used.
<br><dt><code>-mv850e2</code><dd><a name="index-mv850e2-2608"></a>Specify that the target processor is the V850E2. The preprocessor
constant <code>__v850e2__</code> is defined if this option is used.
<br><dt><code>-mv850e1</code><dd><a name="index-mv850e1-2609"></a>Specify that the target processor is the V850E1. The preprocessor
constants <code>__v850e1__</code> and <code>__v850e__</code> are defined if
this option is used.
<br><dt><code>-mv850es</code><dd><a name="index-mv850es-2610"></a>Specify that the target processor is the V850ES. This is an alias for
the <samp><span class="option">-mv850e1</span></samp> option.
<br><dt><code>-mv850e</code><dd><a name="index-mv850e-2611"></a>Specify that the target processor is the V850E. The preprocessor
constant <code>__v850e__</code> is defined if this option is used.
<p>If neither <samp><span class="option">-mv850</span></samp> nor <samp><span class="option">-mv850e</span></samp> nor <samp><span class="option">-mv850e1</span></samp>
nor <samp><span class="option">-mv850e2</span></samp> nor <samp><span class="option">-mv850e2v3</span></samp> nor <samp><span class="option">-mv850e3v5</span></samp>
are defined then a default target processor is chosen and the
relevant ‘<samp><span class="samp">__v850*__</span></samp>’ preprocessor constant is defined.
<p>The preprocessor constants <code>__v850</code> and <code>__v851__</code> are always
defined, regardless of which processor variant is the target.
<br><dt><code>-mdisable-callt</code><dt><code>-mno-disable-callt</code><dd><a name="index-mdisable_002dcallt-2612"></a><a name="index-mno_002ddisable_002dcallt-2613"></a>This option suppresses generation of the <code>CALLT</code> instruction for the
v850e, v850e1, v850e2, v850e2v3 and v850e3v5 flavors of the v850
architecture.
<p>This option is enabled by default when the RH850 ABI is
in use (see <samp><span class="option">-mrh850-abi</span></samp>), and disabled by default when the
GCC ABI is in use. If <code>CALLT</code> instructions are being generated
then the C preprocessor symbol <code>__V850_CALLT__</code> is defined.
<br><dt><code>-mrelax</code><dt><code>-mno-relax</code><dd><a name="index-mrelax-2614"></a><a name="index-mno_002drelax-2615"></a>Pass on (or do not pass on) the <samp><span class="option">-mrelax</span></samp> command-line option
to the assembler.
<br><dt><code>-mlong-jumps</code><dt><code>-mno-long-jumps</code><dd><a name="index-mlong_002djumps-2616"></a><a name="index-mno_002dlong_002djumps-2617"></a>Disable (or re-enable) the generation of PC-relative jump instructions.
<br><dt><code>-msoft-float</code><dt><code>-mhard-float</code><dd><a name="index-msoft_002dfloat-2618"></a><a name="index-mhard_002dfloat-2619"></a>Disable (or re-enable) the generation of hardware floating point
instructions. This option is only significant when the target
architecture is ‘<samp><span class="samp">V850E2V3</span></samp>’ or higher. If hardware floating point
instructions are being generated then the C preprocessor symbol
<code>__FPU_OK__</code> is defined, otherwise the symbol
<code>__NO_FPU__</code> is defined.
<br><dt><code>-mloop</code><dd><a name="index-mloop-2620"></a>Enables the use of the e3v5 LOOP instruction. The use of this
instruction is not enabled by default when the e3v5 architecture is
selected because its use is still experimental.
<br><dt><code>-mrh850-abi</code><dt><code>-mghs</code><dd><a name="index-mrh850_002dabi-2621"></a><a name="index-mghs-2622"></a>Enables support for the RH850 version of the V850 ABI. This is the
default. With this version of the ABI the following rules apply:
<ul>
<li>Integer sized structures and unions are returned via a memory pointer
rather than a register.
<li>Large structures and unions (more than 8 bytes in size) are passed by
value.
<li>Functions are aligned to 16-bit boundaries.
<li>The <samp><span class="option">-m8byte-align</span></samp> command-line option is supported.
<li>The <samp><span class="option">-mdisable-callt</span></samp> command-line option is enabled by
default. The <samp><span class="option">-mno-disable-callt</span></samp> command-line option is not
supported.
</ul>
<p>When this version of the ABI is enabled the C preprocessor symbol
<code>__V850_RH850_ABI__</code> is defined.
<br><dt><code>-mgcc-abi</code><dd><a name="index-mgcc_002dabi-2623"></a>Enables support for the old GCC version of the V850 ABI. With this
version of the ABI the following rules apply:
<ul>
<li>Integer sized structures and unions are returned in register <code>r10</code>.
<li>Large structures and unions (more than 8 bytes in size) are passed by
reference.
<li>Functions are aligned to 32-bit boundaries, unless optimizing for
size.
<li>The <samp><span class="option">-m8byte-align</span></samp> command-line option is not supported.
<li>The <samp><span class="option">-mdisable-callt</span></samp> command-line option is supported but not
enabled by default.
</ul>
<p>When this version of the ABI is enabled the C preprocessor symbol
<code>__V850_GCC_ABI__</code> is defined.
<br><dt><code>-m8byte-align</code><dt><code>-mno-8byte-align</code><dd><a name="index-m8byte_002dalign-2624"></a><a name="index-mno_002d8byte_002dalign-2625"></a>Enables support for <code>double</code> and <code>long long</code> types to be
aligned on 8-byte boundaries. The default is to restrict the
alignment of all objects to at most 4-bytes. When
<samp><span class="option">-m8byte-align</span></samp> is in effect the C preprocessor symbol
<code>__V850_8BYTE_ALIGN__</code> is defined.
<br><dt><code>-mbig-switch</code><dd><a name="index-mbig_002dswitch-2626"></a>Generate code suitable for big switch tables. Use this option only if
the assembler/linker complain about out of range branches within a switch
table.
<br><dt><code>-mapp-regs</code><dd><a name="index-mapp_002dregs-2627"></a>This option causes r2 and r5 to be used in the code generated by
the compiler. This setting is the default.
<br><dt><code>-mno-app-regs</code><dd><a name="index-mno_002dapp_002dregs-2628"></a>This option causes r2 and r5 to be treated as fixed registers.
</dl>
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