diff options
| -rw-r--r-- | docs/LangRef.html | 116 |
1 files changed, 95 insertions, 21 deletions
diff --git a/docs/LangRef.html b/docs/LangRef.html index 3215586f86..de0ac2efdf 100644 --- a/docs/LangRef.html +++ b/docs/LangRef.html @@ -80,6 +80,7 @@ <ol> <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li> <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li> + <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li> <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li> <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li> <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li> @@ -1506,38 +1507,111 @@ came from in the last <a href="#terminators">terminator</a> instruction.</p> <h5>Example:</h5> <pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre> </div> + <!-- _______________________________________________________________________ --> -<div class="doc_subsubsection"> <a name="i_cast">'<tt>cast .. to</tt>' -Instruction</a> </div> +<div class="doc_subsubsection"> + <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a> +</div> + <div class="doc_text"> + <h5>Syntax:</h5> -<pre> <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i> + +<pre> + <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i> </pre> + <h5>Overview:</h5> -<p>The '<tt>cast</tt>' instruction is used as the primitive means to -convert integers to floating point, change data type sizes, and break -type safety (by casting pointers).</p> + +<p> +The '<tt>cast</tt>' instruction is used as the primitive means to convert +integers to floating point, change data type sizes, and break type safety (by +casting pointers). +</p> + + <h5>Arguments:</h5> -<p>The '<tt>cast</tt>' instruction takes a value to cast, which must be -a first class value, and a type to cast it to, which must also be a <a - href="#t_firstclass">first class</a> type.</p> + +<p> +The '<tt>cast</tt>' instruction takes a value to cast, which must be a first +class value, and a type to cast it to, which must also be a <a +href="#t_firstclass">first class</a> type. +</p> + <h5>Semantics:</h5> -<p>This instruction follows the C rules for explicit casts when -determining how the data being cast must change to fit in its new -container.</p> -<p>When casting to bool, any value that would be considered true in the -context of a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' -values, all else are '<tt>false</tt>'.</p> -<p>When extending an integral value from a type of one signness to -another (for example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value -is sign-extended if the <b>source</b> value is signed, and -zero-extended if the source value is unsigned. <tt>bool</tt> values -are always zero extended into either zero or one.</p> + +<p> +This instruction follows the C rules for explicit casts when determining how the +data being cast must change to fit in its new container. +</p> + +<p> +When casting to bool, any value that would be considered true in the context of +a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values, +all else are '<tt>false</tt>'. +</p> + +<p> +When extending an integral value from a type of one signness to another (for +example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the +<b>source</b> value is signed, and zero-extended if the source value is +unsigned. <tt>bool</tt> values are always zero extended into either zero or +one. +</p> + <h5>Example:</h5> -<pre> %X = cast int 257 to ubyte <i>; yields ubyte:1</i> + +<pre> + %X = cast int 257 to ubyte <i>; yields ubyte:1</i> %Y = cast int 123 to bool <i>; yields bool:true</i> </pre> </div> + +<!-- _______________________________________________________________________ --> +<div class="doc_subsubsection"> + <a name="i_select">'<tt>select</tt>' Instruction</a> +</div> + +<div class="doc_text"> + +<h5>Syntax:</h5> + +<pre> + <result> = select bool <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i> +</pre> + +<h5>Overview:</h5> + +<p> +The '<tt>select</tt>' instruction is used to choose one value based on a +condition, without branching. +</p> + + +<h5>Arguments:</h5> + +<p> +The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type. +</p> + +<h5>Semantics:</h5> + +<p> +If the boolean condition evaluates to true, the instruction returns the first +value argument, otherwise it returns the second value argument. +</p> + +<h5>Example:</h5> + +<pre> + %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i> +</pre> +</div> + + + + + <!-- _______________________________________________________________________ --> <div class="doc_subsubsection"> <a name="i_call">'<tt>call</tt>' Instruction</a> </div> |