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| <a name="Machine-Modes"></a> |
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| <a name="Machine-Modes-1"></a> |
| <h3 class="section">13.6 Machine Modes</h3> |
| <a name="index-machine-modes"></a> |
| |
| <a name="index-enum-machine_005fmode"></a> |
| <p>A machine mode describes a size of data object and the representation used |
| for it. In the C code, machine modes are represented by an enumeration |
| type, <code>enum machine_mode</code>, defined in <samp>machmode.def</samp>. Each RTL |
| expression has room for a machine mode and so do certain kinds of tree |
| expressions (declarations and types, to be precise). |
| </p> |
| <p>In debugging dumps and machine descriptions, the machine mode of an RTL |
| expression is written after the expression code with a colon to separate |
| them. The letters ‘<samp>mode</samp>’ which appear at the end of each machine mode |
| name are omitted. For example, <code>(reg:SI 38)</code> is a <code>reg</code> |
| expression with machine mode <code>SImode</code>. If the mode is |
| <code>VOIDmode</code>, it is not written at all. |
| </p> |
| <p>Here is a table of machine modes. The term “byte” below refers to an |
| object of <code>BITS_PER_UNIT</code> bits (see <a href="Storage-Layout.html#Storage-Layout">Storage Layout</a>). |
| </p> |
| <dl compact="compact"> |
| <dd><a name="index-BImode"></a> |
| </dd> |
| <dt><code>BImode</code></dt> |
| <dd><p>“Bit” mode represents a single bit, for predicate registers. |
| </p> |
| <a name="index-QImode"></a> |
| </dd> |
| <dt><code>QImode</code></dt> |
| <dd><p>“Quarter-Integer” mode represents a single byte treated as an integer. |
| </p> |
| <a name="index-HImode"></a> |
| </dd> |
| <dt><code>HImode</code></dt> |
| <dd><p>“Half-Integer” mode represents a two-byte integer. |
| </p> |
| <a name="index-PSImode"></a> |
| </dd> |
| <dt><code>PSImode</code></dt> |
| <dd><p>“Partial Single Integer” mode represents an integer which occupies |
| four bytes but which doesn’t really use all four. On some machines, |
| this is the right mode to use for pointers. |
| </p> |
| <a name="index-SImode"></a> |
| </dd> |
| <dt><code>SImode</code></dt> |
| <dd><p>“Single Integer” mode represents a four-byte integer. |
| </p> |
| <a name="index-PDImode"></a> |
| </dd> |
| <dt><code>PDImode</code></dt> |
| <dd><p>“Partial Double Integer” mode represents an integer which occupies |
| eight bytes but which doesn’t really use all eight. On some machines, |
| this is the right mode to use for certain pointers. |
| </p> |
| <a name="index-DImode"></a> |
| </dd> |
| <dt><code>DImode</code></dt> |
| <dd><p>“Double Integer” mode represents an eight-byte integer. |
| </p> |
| <a name="index-TImode"></a> |
| </dd> |
| <dt><code>TImode</code></dt> |
| <dd><p>“Tetra Integer” (?) mode represents a sixteen-byte integer. |
| </p> |
| <a name="index-OImode"></a> |
| </dd> |
| <dt><code>OImode</code></dt> |
| <dd><p>“Octa Integer” (?) mode represents a thirty-two-byte integer. |
| </p> |
| <a name="index-XImode"></a> |
| </dd> |
| <dt><code>XImode</code></dt> |
| <dd><p>“Hexadeca Integer” (?) mode represents a sixty-four-byte integer. |
| </p> |
| <a name="index-QFmode"></a> |
| </dd> |
| <dt><code>QFmode</code></dt> |
| <dd><p>“Quarter-Floating” mode represents a quarter-precision (single byte) |
| floating point number. |
| </p> |
| <a name="index-HFmode"></a> |
| </dd> |
| <dt><code>HFmode</code></dt> |
| <dd><p>“Half-Floating” mode represents a half-precision (two byte) floating |
| point number. |
| </p> |
| <a name="index-TQFmode"></a> |
| </dd> |
| <dt><code>TQFmode</code></dt> |
| <dd><p>“Three-Quarter-Floating” (?) mode represents a three-quarter-precision |
| (three byte) floating point number. |
| </p> |
| <a name="index-SFmode"></a> |
| </dd> |
| <dt><code>SFmode</code></dt> |
| <dd><p>“Single Floating” mode represents a four byte floating point number. |
| In the common case, of a processor with IEEE arithmetic and 8-bit bytes, |
| this is a single-precision IEEE floating point number; it can also be |
| used for double-precision (on processors with 16-bit bytes) and |
| single-precision VAX and IBM types. |
| </p> |
| <a name="index-DFmode"></a> |
| </dd> |
| <dt><code>DFmode</code></dt> |
| <dd><p>“Double Floating” mode represents an eight byte floating point number. |
| In the common case, of a processor with IEEE arithmetic and 8-bit bytes, |
| this is a double-precision IEEE floating point number. |
| </p> |
| <a name="index-XFmode"></a> |
| </dd> |
| <dt><code>XFmode</code></dt> |
| <dd><p>“Extended Floating” mode represents an IEEE extended floating point |
| number. This mode only has 80 meaningful bits (ten bytes). Some |
| processors require such numbers to be padded to twelve bytes, others |
| to sixteen; this mode is used for either. |
| </p> |
| <a name="index-SDmode"></a> |
| </dd> |
| <dt><code>SDmode</code></dt> |
| <dd><p>“Single Decimal Floating” mode represents a four byte decimal |
| floating point number (as distinct from conventional binary floating |
| point). |
| </p> |
| <a name="index-DDmode"></a> |
| </dd> |
| <dt><code>DDmode</code></dt> |
| <dd><p>“Double Decimal Floating” mode represents an eight byte decimal |
| floating point number. |
| </p> |
| <a name="index-TDmode"></a> |
| </dd> |
| <dt><code>TDmode</code></dt> |
| <dd><p>“Tetra Decimal Floating” mode represents a sixteen byte decimal |
| floating point number all 128 of whose bits are meaningful. |
| </p> |
| <a name="index-TFmode"></a> |
| </dd> |
| <dt><code>TFmode</code></dt> |
| <dd><p>“Tetra Floating” mode represents a sixteen byte floating point number |
| all 128 of whose bits are meaningful. One common use is the |
| IEEE quad-precision format. |
| </p> |
| <a name="index-QQmode"></a> |
| </dd> |
| <dt><code>QQmode</code></dt> |
| <dd><p>“Quarter-Fractional” mode represents a single byte treated as a signed |
| fractional number. The default format is “s.7”. |
| </p> |
| <a name="index-HQmode"></a> |
| </dd> |
| <dt><code>HQmode</code></dt> |
| <dd><p>“Half-Fractional” mode represents a two-byte signed fractional number. |
| The default format is “s.15”. |
| </p> |
| <a name="index-SQmode"></a> |
| </dd> |
| <dt><code>SQmode</code></dt> |
| <dd><p>“Single Fractional” mode represents a four-byte signed fractional number. |
| The default format is “s.31”. |
| </p> |
| <a name="index-DQmode"></a> |
| </dd> |
| <dt><code>DQmode</code></dt> |
| <dd><p>“Double Fractional” mode represents an eight-byte signed fractional number. |
| The default format is “s.63”. |
| </p> |
| <a name="index-TQmode"></a> |
| </dd> |
| <dt><code>TQmode</code></dt> |
| <dd><p>“Tetra Fractional” mode represents a sixteen-byte signed fractional number. |
| The default format is “s.127”. |
| </p> |
| <a name="index-UQQmode"></a> |
| </dd> |
| <dt><code>UQQmode</code></dt> |
| <dd><p>“Unsigned Quarter-Fractional” mode represents a single byte treated as an |
| unsigned fractional number. The default format is “.8”. |
| </p> |
| <a name="index-UHQmode"></a> |
| </dd> |
| <dt><code>UHQmode</code></dt> |
| <dd><p>“Unsigned Half-Fractional” mode represents a two-byte unsigned fractional |
| number. The default format is “.16”. |
| </p> |
| <a name="index-USQmode"></a> |
| </dd> |
| <dt><code>USQmode</code></dt> |
| <dd><p>“Unsigned Single Fractional” mode represents a four-byte unsigned fractional |
| number. The default format is “.32”. |
| </p> |
| <a name="index-UDQmode"></a> |
| </dd> |
| <dt><code>UDQmode</code></dt> |
| <dd><p>“Unsigned Double Fractional” mode represents an eight-byte unsigned |
| fractional number. The default format is “.64”. |
| </p> |
| <a name="index-UTQmode"></a> |
| </dd> |
| <dt><code>UTQmode</code></dt> |
| <dd><p>“Unsigned Tetra Fractional” mode represents a sixteen-byte unsigned |
| fractional number. The default format is “.128”. |
| </p> |
| <a name="index-HAmode"></a> |
| </dd> |
| <dt><code>HAmode</code></dt> |
| <dd><p>“Half-Accumulator” mode represents a two-byte signed accumulator. |
| The default format is “s8.7”. |
| </p> |
| <a name="index-SAmode"></a> |
| </dd> |
| <dt><code>SAmode</code></dt> |
| <dd><p>“Single Accumulator” mode represents a four-byte signed accumulator. |
| The default format is “s16.15”. |
| </p> |
| <a name="index-DAmode"></a> |
| </dd> |
| <dt><code>DAmode</code></dt> |
| <dd><p>“Double Accumulator” mode represents an eight-byte signed accumulator. |
| The default format is “s32.31”. |
| </p> |
| <a name="index-TAmode"></a> |
| </dd> |
| <dt><code>TAmode</code></dt> |
| <dd><p>“Tetra Accumulator” mode represents a sixteen-byte signed accumulator. |
| The default format is “s64.63”. |
| </p> |
| <a name="index-UHAmode"></a> |
| </dd> |
| <dt><code>UHAmode</code></dt> |
| <dd><p>“Unsigned Half-Accumulator” mode represents a two-byte unsigned accumulator. |
| The default format is “8.8”. |
| </p> |
| <a name="index-USAmode"></a> |
| </dd> |
| <dt><code>USAmode</code></dt> |
| <dd><p>“Unsigned Single Accumulator” mode represents a four-byte unsigned |
| accumulator. The default format is “16.16”. |
| </p> |
| <a name="index-UDAmode"></a> |
| </dd> |
| <dt><code>UDAmode</code></dt> |
| <dd><p>“Unsigned Double Accumulator” mode represents an eight-byte unsigned |
| accumulator. The default format is “32.32”. |
| </p> |
| <a name="index-UTAmode"></a> |
| </dd> |
| <dt><code>UTAmode</code></dt> |
| <dd><p>“Unsigned Tetra Accumulator” mode represents a sixteen-byte unsigned |
| accumulator. The default format is “64.64”. |
| </p> |
| <a name="index-CCmode"></a> |
| </dd> |
| <dt><code>CCmode</code></dt> |
| <dd><p>“Condition Code” mode represents the value of a condition code, which |
| is a machine-specific set of bits used to represent the result of a |
| comparison operation. Other machine-specific modes may also be used for |
| the condition code. These modes are not used on machines that use |
| <code>cc0</code> (see <a href="Condition-Code.html#Condition-Code">Condition Code</a>). |
| </p> |
| <a name="index-BLKmode"></a> |
| </dd> |
| <dt><code>BLKmode</code></dt> |
| <dd><p>“Block” mode represents values that are aggregates to which none of |
| the other modes apply. In RTL, only memory references can have this mode, |
| and only if they appear in string-move or vector instructions. On machines |
| which have no such instructions, <code>BLKmode</code> will not appear in RTL. |
| </p> |
| <a name="index-VOIDmode"></a> |
| </dd> |
| <dt><code>VOIDmode</code></dt> |
| <dd><p>Void mode means the absence of a mode or an unspecified mode. |
| For example, RTL expressions of code <code>const_int</code> have mode |
| <code>VOIDmode</code> because they can be taken to have whatever mode the context |
| requires. In debugging dumps of RTL, <code>VOIDmode</code> is expressed by |
| the absence of any mode. |
| </p> |
| <a name="index-QCmode"></a> |
| <a name="index-HCmode"></a> |
| <a name="index-SCmode"></a> |
| <a name="index-DCmode"></a> |
| <a name="index-XCmode"></a> |
| <a name="index-TCmode"></a> |
| </dd> |
| <dt><code>QCmode, HCmode, SCmode, DCmode, XCmode, TCmode</code></dt> |
| <dd><p>These modes stand for a complex number represented as a pair of floating |
| point values. The floating point values are in <code>QFmode</code>, |
| <code>HFmode</code>, <code>SFmode</code>, <code>DFmode</code>, <code>XFmode</code>, and |
| <code>TFmode</code>, respectively. |
| </p> |
| <a name="index-CQImode"></a> |
| <a name="index-CHImode"></a> |
| <a name="index-CSImode"></a> |
| <a name="index-CDImode"></a> |
| <a name="index-CTImode"></a> |
| <a name="index-COImode"></a> |
| </dd> |
| <dt><code>CQImode, CHImode, CSImode, CDImode, CTImode, COImode</code></dt> |
| <dd><p>These modes stand for a complex number represented as a pair of integer |
| values. The integer values are in <code>QImode</code>, <code>HImode</code>, |
| <code>SImode</code>, <code>DImode</code>, <code>TImode</code>, and <code>OImode</code>, |
| respectively. |
| </p></dd> |
| </dl> |
| |
| <p>The machine description defines <code>Pmode</code> as a C macro which expands |
| into the machine mode used for addresses. Normally this is the mode |
| whose size is <code>BITS_PER_WORD</code>, <code>SImode</code> on 32-bit machines. |
| </p> |
| <p>The only modes which a machine description <i>must</i> support are |
| <code>QImode</code>, and the modes corresponding to <code>BITS_PER_WORD</code>, |
| <code>FLOAT_TYPE_SIZE</code> and <code>DOUBLE_TYPE_SIZE</code>. |
| The compiler will attempt to use <code>DImode</code> for 8-byte structures and |
| unions, but this can be prevented by overriding the definition of |
| <code>MAX_FIXED_MODE_SIZE</code>. Alternatively, you can have the compiler |
| use <code>TImode</code> for 16-byte structures and unions. Likewise, you can |
| arrange for the C type <code>short int</code> to avoid using <code>HImode</code>. |
| </p> |
| <a name="index-mode-classes"></a> |
| <p>Very few explicit references to machine modes remain in the compiler and |
| these few references will soon be removed. Instead, the machine modes |
| are divided into mode classes. These are represented by the enumeration |
| type <code>enum mode_class</code> defined in <samp>machmode.h</samp>. The possible |
| mode classes are: |
| </p> |
| <dl compact="compact"> |
| <dd><a name="index-MODE_005fINT"></a> |
| </dd> |
| <dt><code>MODE_INT</code></dt> |
| <dd><p>Integer modes. By default these are <code>BImode</code>, <code>QImode</code>, |
| <code>HImode</code>, <code>SImode</code>, <code>DImode</code>, <code>TImode</code>, and |
| <code>OImode</code>. |
| </p> |
| <a name="index-MODE_005fPARTIAL_005fINT"></a> |
| </dd> |
| <dt><code>MODE_PARTIAL_INT</code></dt> |
| <dd><p>The “partial integer” modes, <code>PQImode</code>, <code>PHImode</code>, |
| <code>PSImode</code> and <code>PDImode</code>. |
| </p> |
| <a name="index-MODE_005fFLOAT"></a> |
| </dd> |
| <dt><code>MODE_FLOAT</code></dt> |
| <dd><p>Floating point modes. By default these are <code>QFmode</code>, |
| <code>HFmode</code>, <code>TQFmode</code>, <code>SFmode</code>, <code>DFmode</code>, |
| <code>XFmode</code> and <code>TFmode</code>. |
| </p> |
| <a name="index-MODE_005fDECIMAL_005fFLOAT"></a> |
| </dd> |
| <dt><code>MODE_DECIMAL_FLOAT</code></dt> |
| <dd><p>Decimal floating point modes. By default these are <code>SDmode</code>, |
| <code>DDmode</code> and <code>TDmode</code>. |
| </p> |
| <a name="index-MODE_005fFRACT"></a> |
| </dd> |
| <dt><code>MODE_FRACT</code></dt> |
| <dd><p>Signed fractional modes. By default these are <code>QQmode</code>, <code>HQmode</code>, |
| <code>SQmode</code>, <code>DQmode</code> and <code>TQmode</code>. |
| </p> |
| <a name="index-MODE_005fUFRACT"></a> |
| </dd> |
| <dt><code>MODE_UFRACT</code></dt> |
| <dd><p>Unsigned fractional modes. By default these are <code>UQQmode</code>, <code>UHQmode</code>, |
| <code>USQmode</code>, <code>UDQmode</code> and <code>UTQmode</code>. |
| </p> |
| <a name="index-MODE_005fACCUM"></a> |
| </dd> |
| <dt><code>MODE_ACCUM</code></dt> |
| <dd><p>Signed accumulator modes. By default these are <code>HAmode</code>, |
| <code>SAmode</code>, <code>DAmode</code> and <code>TAmode</code>. |
| </p> |
| <a name="index-MODE_005fUACCUM"></a> |
| </dd> |
| <dt><code>MODE_UACCUM</code></dt> |
| <dd><p>Unsigned accumulator modes. By default these are <code>UHAmode</code>, |
| <code>USAmode</code>, <code>UDAmode</code> and <code>UTAmode</code>. |
| </p> |
| <a name="index-MODE_005fCOMPLEX_005fINT"></a> |
| </dd> |
| <dt><code>MODE_COMPLEX_INT</code></dt> |
| <dd><p>Complex integer modes. (These are not currently implemented). |
| </p> |
| <a name="index-MODE_005fCOMPLEX_005fFLOAT"></a> |
| </dd> |
| <dt><code>MODE_COMPLEX_FLOAT</code></dt> |
| <dd><p>Complex floating point modes. By default these are <code>QCmode</code>, |
| <code>HCmode</code>, <code>SCmode</code>, <code>DCmode</code>, <code>XCmode</code>, and |
| <code>TCmode</code>. |
| </p> |
| <a name="index-MODE_005fFUNCTION"></a> |
| </dd> |
| <dt><code>MODE_FUNCTION</code></dt> |
| <dd><p>Algol or Pascal function variables including a static chain. |
| (These are not currently implemented). |
| </p> |
| <a name="index-MODE_005fCC"></a> |
| </dd> |
| <dt><code>MODE_CC</code></dt> |
| <dd><p>Modes representing condition code values. These are <code>CCmode</code> plus |
| any <code>CC_MODE</code> modes listed in the <samp><var>machine</var>-modes.def</samp>. |
| See <a href="Jump-Patterns.html#Jump-Patterns">Jump Patterns</a>, |
| also see <a href="Condition-Code.html#Condition-Code">Condition Code</a>. |
| </p> |
| <a name="index-MODE_005fRANDOM"></a> |
| </dd> |
| <dt><code>MODE_RANDOM</code></dt> |
| <dd><p>This is a catchall mode class for modes which don’t fit into the above |
| classes. Currently <code>VOIDmode</code> and <code>BLKmode</code> are in |
| <code>MODE_RANDOM</code>. |
| </p></dd> |
| </dl> |
| |
| <p>Here are some C macros that relate to machine modes: |
| </p> |
| <dl compact="compact"> |
| <dd><a name="index-GET_005fMODE"></a> |
| </dd> |
| <dt><code>GET_MODE (<var>x</var>)</code></dt> |
| <dd><p>Returns the machine mode of the RTX <var>x</var>. |
| </p> |
| <a name="index-PUT_005fMODE"></a> |
| </dd> |
| <dt><code>PUT_MODE (<var>x</var>, <var>newmode</var>)</code></dt> |
| <dd><p>Alters the machine mode of the RTX <var>x</var> to be <var>newmode</var>. |
| </p> |
| <a name="index-NUM_005fMACHINE_005fMODES"></a> |
| </dd> |
| <dt><code>NUM_MACHINE_MODES</code></dt> |
| <dd><p>Stands for the number of machine modes available on the target |
| machine. This is one greater than the largest numeric value of any |
| machine mode. |
| </p> |
| <a name="index-GET_005fMODE_005fNAME"></a> |
| </dd> |
| <dt><code>GET_MODE_NAME (<var>m</var>)</code></dt> |
| <dd><p>Returns the name of mode <var>m</var> as a string. |
| </p> |
| <a name="index-GET_005fMODE_005fCLASS"></a> |
| </dd> |
| <dt><code>GET_MODE_CLASS (<var>m</var>)</code></dt> |
| <dd><p>Returns the mode class of mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fWIDER_005fMODE"></a> |
| </dd> |
| <dt><code>GET_MODE_WIDER_MODE (<var>m</var>)</code></dt> |
| <dd><p>Returns the next wider natural mode. For example, the expression |
| <code>GET_MODE_WIDER_MODE (QImode)</code> returns <code>HImode</code>. |
| </p> |
| <a name="index-GET_005fMODE_005fSIZE"></a> |
| </dd> |
| <dt><code>GET_MODE_SIZE (<var>m</var>)</code></dt> |
| <dd><p>Returns the size in bytes of a datum of mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fBITSIZE"></a> |
| </dd> |
| <dt><code>GET_MODE_BITSIZE (<var>m</var>)</code></dt> |
| <dd><p>Returns the size in bits of a datum of mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fIBIT"></a> |
| </dd> |
| <dt><code>GET_MODE_IBIT (<var>m</var>)</code></dt> |
| <dd><p>Returns the number of integral bits of a datum of fixed-point mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fFBIT"></a> |
| </dd> |
| <dt><code>GET_MODE_FBIT (<var>m</var>)</code></dt> |
| <dd><p>Returns the number of fractional bits of a datum of fixed-point mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fMASK"></a> |
| </dd> |
| <dt><code>GET_MODE_MASK (<var>m</var>)</code></dt> |
| <dd><p>Returns a bitmask containing 1 for all bits in a word that fit within |
| mode <var>m</var>. This macro can only be used for modes whose bitsize is |
| less than or equal to <code>HOST_BITS_PER_INT</code>. |
| </p> |
| <a name="index-GET_005fMODE_005fALIGNMENT"></a> |
| </dd> |
| <dt><code>GET_MODE_ALIGNMENT (<var>m</var>)</code></dt> |
| <dd><p>Return the required alignment, in bits, for an object of mode <var>m</var>. |
| </p> |
| <a name="index-GET_005fMODE_005fUNIT_005fSIZE"></a> |
| </dd> |
| <dt><code>GET_MODE_UNIT_SIZE (<var>m</var>)</code></dt> |
| <dd><p>Returns the size in bytes of the subunits of a datum of mode <var>m</var>. |
| This is the same as <code>GET_MODE_SIZE</code> except in the case of complex |
| modes. For them, the unit size is the size of the real or imaginary |
| part. |
| </p> |
| <a name="index-GET_005fMODE_005fNUNITS"></a> |
| </dd> |
| <dt><code>GET_MODE_NUNITS (<var>m</var>)</code></dt> |
| <dd><p>Returns the number of units contained in a mode, i.e., |
| <code>GET_MODE_SIZE</code> divided by <code>GET_MODE_UNIT_SIZE</code>. |
| </p> |
| <a name="index-GET_005fCLASS_005fNARROWEST_005fMODE"></a> |
| </dd> |
| <dt><code>GET_CLASS_NARROWEST_MODE (<var>c</var>)</code></dt> |
| <dd><p>Returns the narrowest mode in mode class <var>c</var>. |
| </p></dd> |
| </dl> |
| |
| <p>The following 3 variables are defined on every target. They can be |
| used to allocate buffers that are guaranteed to be large enough to |
| hold any value that can be represented on the target. The first two |
| can be overridden by defining them in the target’s mode.def file, |
| however, the value must be a constant that can determined very early |
| in the compilation process. The third symbol cannot be overridden. |
| </p> |
| <dl compact="compact"> |
| <dd><a name="index-BITS_005fPER_005fUNIT"></a> |
| </dd> |
| <dt><code>BITS_PER_UNIT</code></dt> |
| <dd><p>The number of bits in an addressable storage unit (byte). If you do |
| not define this, the default is 8. |
| </p> |
| <a name="index-MAX_005fBITSIZE_005fMODE_005fANY_005fINT"></a> |
| </dd> |
| <dt><code>MAX_BITSIZE_MODE_ANY_INT</code></dt> |
| <dd><p>The maximum bitsize of any mode that is used in integer math. This |
| should be overridden by the target if it uses large integers as |
| containers for larger vectors but otherwise never uses the contents to |
| compute integer values. |
| </p> |
| <a name="index-MAX_005fBITSIZE_005fMODE_005fANY_005fMODE"></a> |
| </dd> |
| <dt><code>MAX_BITSIZE_MODE_ANY_MODE</code></dt> |
| <dd><p>The bitsize of the largest mode on the target. |
| </p></dd> |
| </dl> |
| |
| <a name="index-byte_005fmode"></a> |
| <a name="index-word_005fmode"></a> |
| <p>The global variables <code>byte_mode</code> and <code>word_mode</code> contain modes |
| whose classes are <code>MODE_INT</code> and whose bitsizes are either |
| <code>BITS_PER_UNIT</code> or <code>BITS_PER_WORD</code>, respectively. On 32-bit |
| machines, these are <code>QImode</code> and <code>SImode</code>, respectively. |
| </p> |
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