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Count Leading Zeros
lesbattersbie lesbattersbie
over 12 years ago
Note: This was originally posted on 6th April 2009 at
http://forums.arm.com
Using the ARM9 CLZ instruction - I am wondering, generally, how often would it be required to use this function and does it justify its inclusion?
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Jacob Bramley
over 12 years ago
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Note: This was originally posted on 6th April 2009 at http://forums.arm.com It's surprisingly useful when hand-optimizing assembler. I think it has benefits for some cryptographic routines, and it speeds...
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Prabhu Prabhu
over 12 years ago
Note: This was originally posted on 7th April 2009 at
http://forums.arm.com
Normalization is the act of shifting the fractional part in order to make the left bit of the fractional point is one. This normalization is used in IEEE-754 compatible binary floating-point addition/subtraction. Let say you 20 leading zeros in the sum result, you may need 20 instructions to shift left "˜1' to become MSB and count the leading zeros. This count will be used to set the exponent value. Now the CLZ helps to have one instruction to find the count of leading zeros. This will speed up the normalization during binary floating-point addition/subtraction. One of widely used application is the Digital Signal Processing.
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Prabhu Prabhu
over 12 years ago
Note: This was originally posted on 7th April 2009 at
http://forums.arm.com
Normalization is the act of shifting the fractional part in order to make the left bit of the fractional point is one. This normalization is used in IEEE-754 compatible binary floating-point addition/subtraction. Let say you 20 leading zeros in the sum result, you may need 20 instructions to shift left "˜1' to become MSB and count the leading zeros. This count will be used to set the exponent value. Now the CLZ helps to have one instruction to find the count of leading zeros. This will speed up the normalization during binary floating-point addition/subtraction. One of widely used application is the Digital Signal Processing.
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