Category: Computer Organization
-
L3 Microkernel
I learned that with an L3 Microkernel approach, each OS runs in their own address space and that they are indistinguishable from the end-user applications running in user land. Because they run in user land, it seems intuitive that this kill performance due to border crossings (not just necessarily context switching, but address space switching…
-
Swapping values of two variables with XOR
As programmers, we know that we can swap two variables by using a temporary variable. That’s fairly simple and intuitive: given two variables (x and y) that you want to swap, you store x in a temporary variable z, copy y to x, then finally copy z (the temporary) to y. But I learned recently…
-
Here’s some assembly instructions … now write the corresponding C code
A wide grin formed on my face, after successfully completing an exercise (from Computer Systems a Programmer’s perspective) that required me to write C code, based off a sequence of a six assembly instructions: void decode1(long *xp, long *yp, long *zp) { /* xp stored in %rdi, yp in %rsi, zp in %rdx) decode1: movq (%rdi),…