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    <p>You can do it without explicit <code>if</code> by using <code>?:</code> as shown by another poster or by using interesting properties of <code>abs()</code> which lets you compute the maximum or minimum of two values.</p> <p>For example, the expression <code>(a + abs(a))/2</code> returns <code>a</code> for positive numbers and <code>0</code> otherwise (maximum of <code>a</code> and <code>0</code>).</p> <p>This gives</p> <pre><code>unsigned char clip(short value) { short a = (value + abs(value)) / 2; return (a + 255 - abs(a - 255)) / 2; } </code></pre> <p>To convince yourself that this works, here is a test program:</p> <pre><code>#include &lt;stdio.h&gt; unsigned char clip(short value) { short a = (value + abs(value)) / 2; return (a + 255 - abs(a - 255)) / 2; } void test(short value) { printf("clip(%d) = %d\n", value, clip(value)); } int main() { test(0); test(10); test(-10); test(255); test(265); return 0; } </code></pre> <p>When run, this prints</p> <pre><code>clip(0) = 0 clip(10) = 10 clip(-10) = 0 clip(255) = 255 clip(265) = 255 </code></pre> <p>Of course, one may argue that there is probably a test in <code>abs()</code>, but <code>gcc -O3</code> for example compiles it linearly:</p> <pre><code>clip: movswl %di, %edi movl %edi, %edx sarl $31, %edx movl %edx, %eax xorl %edi, %eax subl %edx, %eax addl %edi, %eax movl %eax, %edx shrl $31, %edx addl %eax, %edx sarl %edx movswl %dx, %edx leal 255(%rdx), %eax subl $255, %edx movl %edx, %ecx sarl $31, %ecx xorl %ecx, %edx subl %ecx, %edx subl %edx, %eax movl %eax, %edx shrl $31, %edx addl %edx, %eax sarl %eax ret </code></pre> <p>But note that this will be much more inefficient than your original function, which compiles as:</p> <pre><code>clip: xorl %eax, %eax testw %di, %di js .L1 movl $-1, %eax cmpw $255, %di cmovle %edi, %eax .L1: rep ret </code></pre> <p>But at least it answers your question :)</p>
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    1. POClamping short to unsigned char
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    1. USSamuel Tardieu
    1. USSamuel Tardieu
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    1. COabs also adds extra function call overhead. I would think that abs has a check on value being less than zero.
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      1. USShailesh Kumar
    2. CO@Shailesh Kumar: in fact, GCC doesn't generate function calls or tests for `abs()` in this case as shown in the edited version.
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    3. COHmmm interesting assembly code.
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