środa, 1 stycznia 2014

x86 - ISA where 80% of instructons are unimportant

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Few years ago I counted instructions from many Linux binaries --- 2014 is good year to repeated this experiment and see that nothing has ch...
poniedziałek, 30 grudnia 2013

I accidentally created an infinite loop

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I needed to iterate through all values of 32-bit unsigned integer, so I wrote: #include <stdint.h> for (uint32_t i=0; i <= UINT3...
niedziela, 29 grudnia 2013

Calculate floor value without FPU/SSE instruction

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Presented algorithm works properly for any normalized floating point value, examples are given for double precision numbers (64-bit). Read ...
piątek, 27 grudnia 2013

Convert float to int without FPU/SSE

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This short note shows how normalized floating point value could be safely converted to integer value without assistance of FPU/SSE. Only bas...
środa, 25 grudnia 2013

fopen a directory

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It's not clear how function fopen applied to a directory should behave, manual pages don't say anything about this. So, our common ...
czwartek, 12 grudnia 2013

Extensions to x86 ISA are useless

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Intel announced new extension to SSE : instructions accelerating calculating hashes SHA-1 and SHA256. As everything else added recently to ...
poniedziałek, 9 grudnia 2013

The most complex instruction in x86 ISA

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This instruction is...  FBSTP . The instruction is advanced converter from integer part of floating point number to BCD format. Sounds weird...