I am working on writing my own operating system. So far, my code exceeds 512 bytes, which is too large to fit in a simple boot sector.
I've been optimising/benchmarking some code recently and came across this method:This is called from a performance critical loop elsewhere, so I naturally assumed all those typeof(...) calls were adding unnecessary overhead (a micro-optimisation, I know) and could be moved to private fields within the class. (I'm aware there are better...
An x86 CPU have some instructions that deal with integers and floating-point numbers.For example: the INC instruction increments an integer (which can be stored in memory or in a register) by 1, so the INC instruction "knows" that it should interpret the bits that it is manipulating as an integer....
Just curiosity about the standard sqrt() from math.h on GCC works. I coded my own sqrt() using Newton-Raphson to do it!
Does the x86 standard include Mnemonics or does it just define the opcodes?If it does not include them, is there another standard for the different assemblers?
VS2019, Release, x86.When use return (float&)f; compiler uses.correct resultWhen use return (float const&)f; compiler uses
I wrote this simple assembly code, ran it and looked at the memory location using GDB:It's adding 5 to 6 directly in memory and according to GDB it worked. So this is performing math operations directly in memory instead of CPU registers.
I wrote this simple assembly code, ran it and looked at the memory location using GDB:It's adding 5 to 6 directly in memory and according to GDB it worked. Now writing the same thing in C and compiling it to assembly turns out like this:
Let's say you want to find the first occurrence of a value1 in a sorted array. For small arrays (where things like binary search don't pay off), you can achieve this by simply counting the number of values less than that value: the result is the index you are after.
I got the bellow assembly list as result for JIT compilation for my java program. My understanding the test instruction is useless here because the main idea of the test is