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 <div class="section" id="bitwise-operations">
<h1>Bitwise operations<a class="headerlink" href="#bitwise-operations" title="Permalink to this headline">¶</a></h1>
The header <code class="docutils literal notranslate">qemu/bitops.h</code> provides utility functions for
performing bitwise operations.
<dl class="function">
<dt id="c.set_bit">
void <code class="descname">set_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.set_bit" title="Permalink to this definition">¶</a></dt>
<dd>Set a bit in memory
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>the bit to set</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>the address to start counting from</dd>
</dl>
<dl class="function">
<dt id="c.set_bit_atomic">
void <code class="descname">set_bit_atomic</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.set_bit_atomic" title="Permalink to this definition">¶</a></dt>
<dd>Set a bit in memory atomically
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>the bit to set</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>the address to start counting from</dd>
</dl>
<dl class="function">
<dt id="c.clear_bit">
void <code class="descname">clear_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.clear_bit" title="Permalink to this definition">¶</a></dt>
<dd>Clears a bit in memory
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>Bit to clear</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>Address to start counting from</dd>
</dl>
<dl class="function">
<dt id="c.change_bit">
void <code class="descname">change_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.change_bit" title="Permalink to this definition">¶</a></dt>
<dd>Toggle a bit in memory
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>Bit to change</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>Address to start counting from</dd>
</dl>
<dl class="function">
<dt id="c.test_and_set_bit">
int <code class="descname">test_and_set_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.test_and_set_bit" title="Permalink to this definition">¶</a></dt>
<dd>Set a bit and return its old value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>Bit to set</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>Address to count from</dd>
</dl>
<dl class="function">
<dt id="c.test_and_clear_bit">
int <code class="descname">test_and_clear_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.test_and_clear_bit" title="Permalink to this definition">¶</a></dt>
<dd>Clear a bit and return its old value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>Bit to clear</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>Address to count from</dd>
</dl>
<dl class="function">
<dt id="c.test_and_change_bit">
int <code class="descname">test_and_change_bit</code>(long&nbsp;nr, unsigned long&nbsp;*addr)<a class="headerlink" href="#c.test_and_change_bit" title="Permalink to this definition">¶</a></dt>
<dd>Change a bit and return its old value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>Bit to change</dd>
<dt><code class="docutils literal notranslate">unsigned long *addr</code></dt>
<dd>Address to count from</dd>
</dl>
<dl class="function">
<dt id="c.test_bit">
int <code class="descname">test_bit</code>(long&nbsp;nr, const unsigned long&nbsp;*addr)<a class="headerlink" href="#c.test_bit" title="Permalink to this definition">¶</a></dt>
<dd>Determine whether a bit is set
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">long nr</code></dt>
<dd>bit number to test</dd>
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>Address to start counting from</dd>
</dl>
<dl class="function">
<dt id="c.find_last_bit">
unsigned long <code class="descname">find_last_bit</code>(const unsigned long&nbsp;*addr, unsigned long&nbsp;size)<a class="headerlink" href="#c.find_last_bit" title="Permalink to this definition">¶</a></dt>
<dd>find the last set bit in a memory region
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>The address to start the search at</dd>
<dt><code class="docutils literal notranslate">unsigned long size</code></dt>
<dd>The maximum size to search</dd>
</dl>
Description
Returns the bit number of the last set bit,
or size if there is no set bit in the bitmap.
<dl class="function">
<dt id="c.find_next_bit">
unsigned long <code class="descname">find_next_bit</code>(const unsigned long&nbsp;*addr, unsigned long&nbsp;size, unsigned long&nbsp;offset)<a class="headerlink" href="#c.find_next_bit" title="Permalink to this definition">¶</a></dt>
<dd>find the next set bit in a memory region
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>The address to base the search on</dd>
<dt><code class="docutils literal notranslate">unsigned long size</code></dt>
<dd>The bitmap size in bits</dd>
<dt><code class="docutils literal notranslate">unsigned long offset</code></dt>
<dd>The bitnumber to start searching at</dd>
</dl>
Description
Returns the bit number of the next set bit,
or size if there are no further set bits in the bitmap.
<dl class="function">
<dt id="c.find_next_zero_bit">
unsigned long <code class="descname">find_next_zero_bit</code>(const unsigned long&nbsp;*addr, unsigned long&nbsp;size, unsigned long&nbsp;offset)<a class="headerlink" href="#c.find_next_zero_bit" title="Permalink to this definition">¶</a></dt>
<dd>find the next cleared bit in a memory region
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>The address to base the search on</dd>
<dt><code class="docutils literal notranslate">unsigned long size</code></dt>
<dd>The bitmap size in bits</dd>
<dt><code class="docutils literal notranslate">unsigned long offset</code></dt>
<dd>The bitnumber to start searching at</dd>
</dl>
Description
Returns the bit number of the next cleared bit,
or size if there are no further clear bits in the bitmap.
<dl class="function">
<dt id="c.find_first_bit">
unsigned long <code class="descname">find_first_bit</code>(const unsigned long&nbsp;*addr, unsigned long&nbsp;size)<a class="headerlink" href="#c.find_first_bit" title="Permalink to this definition">¶</a></dt>
<dd>find the first set bit in a memory region
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>The address to start the search at</dd>
<dt><code class="docutils literal notranslate">unsigned long size</code></dt>
<dd>The maximum size to search</dd>
</dl>
Description
Returns the bit number of the first set bit,
or size if there is no set bit in the bitmap.
<dl class="function">
<dt id="c.find_first_zero_bit">
unsigned long <code class="descname">find_first_zero_bit</code>(const unsigned long&nbsp;*addr, unsigned long&nbsp;size)<a class="headerlink" href="#c.find_first_zero_bit" title="Permalink to this definition">¶</a></dt>
<dd>find the first cleared bit in a memory region
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">const unsigned long *addr</code></dt>
<dd>The address to start the search at</dd>
<dt><code class="docutils literal notranslate">unsigned long size</code></dt>
<dd>The maximum size to search</dd>
</dl>
Description
Returns the bit number of the first cleared bit,
or size if there is no clear bit in the bitmap.
<dl class="function">
<dt id="c.rol8">
uint8_t <code class="descname">rol8</code>(uint8_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.rol8" title="Permalink to this definition">¶</a></dt>
<dd>rotate an 8-bit value left
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint8_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.ror8">
uint8_t <code class="descname">ror8</code>(uint8_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.ror8" title="Permalink to this definition">¶</a></dt>
<dd>rotate an 8-bit value right
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint8_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.rol16">
uint16_t <code class="descname">rol16</code>(uint16_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.rol16" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 16-bit value left
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint16_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.ror16">
uint16_t <code class="descname">ror16</code>(uint16_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.ror16" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 16-bit value right
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint16_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.rol32">
uint32_t <code class="descname">rol32</code>(uint32_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.rol32" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 32-bit value left
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.ror32">
uint32_t <code class="descname">ror32</code>(uint32_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.ror32" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 32-bit value right
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.rol64">
uint64_t <code class="descname">rol64</code>(uint64_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.rol64" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 64-bit value left
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.ror64">
uint64_t <code class="descname">ror64</code>(uint64_t&nbsp;word, unsigned int&nbsp;shift)<a class="headerlink" href="#c.ror64" title="Permalink to this definition">¶</a></dt>
<dd>rotate a 64-bit value right
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t word</code></dt>
<dd>value to rotate</dd>
<dt><code class="docutils literal notranslate">unsigned int shift</code></dt>
<dd>bits to roll</dd>
</dl>
<dl class="function">
<dt id="c.hswap32">
uint32_t <code class="descname">hswap32</code>(uint32_t&nbsp;h)<a class="headerlink" href="#c.hswap32" title="Permalink to this definition">¶</a></dt>
<dd>swap 16-bit halfwords within a 32-bit value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t h</code></dt>
<dd>value to swap</dd>
</dl>
<dl class="function">
<dt id="c.hswap64">
uint64_t <code class="descname">hswap64</code>(uint64_t&nbsp;h)<a class="headerlink" href="#c.hswap64" title="Permalink to this definition">¶</a></dt>
<dd>swap 16-bit halfwords within a 64-bit value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t h</code></dt>
<dd>value to swap</dd>
</dl>
<dl class="function">
<dt id="c.wswap64">
uint64_t <code class="descname">wswap64</code>(uint64_t&nbsp;h)<a class="headerlink" href="#c.wswap64" title="Permalink to this definition">¶</a></dt>
<dd>swap 32-bit words within a 64-bit value
</dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t h</code></dt>
<dd>value to swap</dd>
</dl>
<dl class="function">
<dt id="c.extract32">
uint32_t <code class="descname">extract32</code>(uint32_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.extract32" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 32 bit input value the bit field specified by the
start and length parameters, and return it. The bit field must
lie entirely within the 32 bit word. It is valid to request that
all 32 bits are returned (ie length 32 and start 0).
Return
the value of the bit field extracted from the input value.
<dl class="function">
<dt id="c.extract8">
uint8_t <code class="descname">extract8</code>(uint8_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.extract8" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint8_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 8 bit input value the bit field specified by the
start and length parameters, and return it. The bit field must
lie entirely within the 8 bit word. It is valid to request that
all 8 bits are returned (ie length 8 and start 0).
Return
the value of the bit field extracted from the input value.
<dl class="function">
<dt id="c.extract16">
uint16_t <code class="descname">extract16</code>(uint16_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.extract16" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint16_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 16 bit input value the bit field specified by the
start and length parameters, and return it. The bit field must
lie entirely within the 16 bit word. It is valid to request that
all 16 bits are returned (ie length 16 and start 0).
Return
the value of the bit field extracted from the input value.
<dl class="function">
<dt id="c.extract64">
uint64_t <code class="descname">extract64</code>(uint64_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.extract64" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 64 bit input value the bit field specified by the
start and length parameters, and return it. The bit field must
lie entirely within the 64 bit word. It is valid to request that
all 64 bits are returned (ie length 64 and start 0).
Return
the value of the bit field extracted from the input value.
<dl class="function">
<dt id="c.sextract32">
int32_t <code class="descname">sextract32</code>(uint32_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.sextract32" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 32 bit input value the bit field specified by the
start and length parameters, and return it, sign extended to
an int32_t (ie with the most significant bit of the field propagated
to all the upper bits of the return value). The bit field must lie
entirely within the 32 bit word. It is valid to request that
all 32 bits are returned (ie length 32 and start 0).
Return
the sign extended value of the bit field extracted from the
input value.
<dl class="function">
<dt id="c.sextract64">
int64_t <code class="descname">sextract64</code>(uint64_t&nbsp;value, int&nbsp;start, int&nbsp;length)<a class="headerlink" href="#c.sextract64" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t value</code></dt>
<dd>the value to extract the bit field from</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
</dl>
Description
Extract from the 64 bit input value the bit field specified by the
start and length parameters, and return it, sign extended to
an int64_t (ie with the most significant bit of the field propagated
to all the upper bits of the return value). The bit field must lie
entirely within the 64 bit word. It is valid to request that
all 64 bits are returned (ie length 64 and start 0).
Return
the sign extended value of the bit field extracted from the
input value.
<dl class="function">
<dt id="c.deposit32">
uint32_t <code class="descname">deposit32</code>(uint32_t&nbsp;value, int&nbsp;start, int&nbsp;length, uint32_t&nbsp;fieldval)<a class="headerlink" href="#c.deposit32" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t value</code></dt>
<dd>initial value to insert bit field into</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
<dt><code class="docutils literal notranslate">uint32_t fieldval</code></dt>
<dd>the value to insert into the bit field</dd>
</dl>
Description
Deposit fieldval into the 32 bit value at the bit field specified
by the start and length parameters, and return the modified
value. Bits of value outside the bit field are not modified.
Bits of fieldval above the least significant length bits are
ignored. The bit field must lie entirely within the 32 bit word.
It is valid to request that all 32 bits are modified (ie length
32 and start 0).
Return
the modified value.
<dl class="function">
<dt id="c.deposit64">
uint64_t <code class="descname">deposit64</code>(uint64_t&nbsp;value, int&nbsp;start, int&nbsp;length, uint64_t&nbsp;fieldval)<a class="headerlink" href="#c.deposit64" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t value</code></dt>
<dd>initial value to insert bit field into</dd>
<dt><code class="docutils literal notranslate">int start</code></dt>
<dd>the lowest bit in the bit field (numbered from 0)</dd>
<dt><code class="docutils literal notranslate">int length</code></dt>
<dd>the length of the bit field</dd>
<dt><code class="docutils literal notranslate">uint64_t fieldval</code></dt>
<dd>the value to insert into the bit field</dd>
</dl>
Description
Deposit fieldval into the 64 bit value at the bit field specified
by the start and length parameters, and return the modified
value. Bits of value outside the bit field are not modified.
Bits of fieldval above the least significant length bits are
ignored. The bit field must lie entirely within the 64 bit word.
It is valid to request that all 64 bits are modified (ie length
64 and start 0).
Return
the modified value.
<dl class="function">
<dt id="c.half_shuffle32">
uint32_t <code class="descname">half_shuffle32</code>(uint32_t&nbsp;x)<a class="headerlink" href="#c.half_shuffle32" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t x</code></dt>
<dd>32-bit value (of which only the bottom 16 bits are of interest)</dd>
</dl>
Description
Given an input value:
<div class="highlight-default notranslate"><div class="highlight"><pre>xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP
</pre></div>
</div>
return the value where the bottom 16 bits are spread out into
the odd bits in the word, and the even bits are zeroed:
<div class="highlight-default notranslate"><div class="highlight"><pre>0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P
</pre></div>
</div>
Any bits set in the top half of the input are ignored.
Return
the shuffled bits.
<dl class="function">
<dt id="c.half_shuffle64">
uint64_t <code class="descname">half_shuffle64</code>(uint64_t&nbsp;x)<a class="headerlink" href="#c.half_shuffle64" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t x</code></dt>
<dd>64-bit value (of which only the bottom 32 bits are of interest)</dd>
</dl>
Description
Given an input value:
<div class="highlight-default notranslate"><div class="highlight"><pre>xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
</pre></div>
</div>
return the value where the bottom 32 bits are spread out into
the odd bits in the word, and the even bits are zeroed:
<div class="highlight-default notranslate"><div class="highlight"><pre>0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f
</pre></div>
</div>
Any bits set in the top half of the input are ignored.
Return
the shuffled bits.
<dl class="function">
<dt id="c.half_unshuffle32">
uint32_t <code class="descname">half_unshuffle32</code>(uint32_t&nbsp;x)<a class="headerlink" href="#c.half_unshuffle32" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint32_t x</code></dt>
<dd>32-bit value (of which only the odd bits are of interest)</dd>
</dl>
Description
Given an input value:
<div class="highlight-default notranslate"><div class="highlight"><pre>xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP
</pre></div>
</div>
return the value where all the odd bits are compressed down
into the low half of the word, and the high half is zeroed:
<div class="highlight-default notranslate"><div class="highlight"><pre>0000 0000 0000 0000 ABCD EFGH IJKL MNOP
</pre></div>
</div>
Any even bits set in the input are ignored.
Return
the unshuffled bits.
<dl class="function">
<dt id="c.half_unshuffle64">
uint64_t <code class="descname">half_unshuffle64</code>(uint64_t&nbsp;x)<a class="headerlink" href="#c.half_unshuffle64" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

Parameters
<dl class="docutils">
<dt><code class="docutils literal notranslate">uint64_t x</code></dt>
<dd>64-bit value (of which only the odd bits are of interest)</dd>
</dl>
Description
Given an input value:
<div class="highlight-default notranslate"><div class="highlight"><pre>xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf
</pre></div>
</div>
return the value where all the odd bits are compressed down
into the low half of the word, and the high half is zeroed:
<div class="highlight-default notranslate"><div class="highlight"><pre>0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
</pre></div>
</div>
Any even bits set in the input are ignored.
Return
the unshuffled bits.
</div>

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