cpu-architecture

I have an old project, that I recompiled for an uodate, and it is now showing this error message: …. missing required architecture x86_64 in file myLibrary.a …. I have tried various tricks that I could find on the net after searching on missing required architecture x86_64 in file , but with no success. Anyone knows how to properly handle the issue? I am using Xcode Version 7.0.1. Running: lipo -info myLibrary.a shows: Architectures in the fat file: myLibrary.a are: armv7 arm64 I have been able to add armv7s but not x86_64. You are trying to build a universal library and it does not have all

I am on the hook to analyze some "timing channels" of some x86 binary code. I am posting one question to comprehend the bsf/bsr opcodes. So high-levelly, these two opcodes can be modeled as a "loop", which counts the leading and trailing zeros of a given operand. The x86 manual has a good formalization of these opcodes, something like the following: IF SRC = 0 THEN ZF ← 1; DEST is undefined; ELSE ZF ← 0; temp ← OperandSize – 1; WHILE Bit(SRC, temp) = 0 DO temp ← temp - 1; OD; DEST ← temp; FI; But to my suprise, bsf/bsr instructions seem to have fixed cpu cycles . According to some documents I

I am building a cache simulator for a intel core i7 but have a hard time finding the detailed specifications for the L1, L2 and L3 cache (shared). I need the Cacheblock size, cache size, associativity and so on... Can anyone point me in the good direction? Intel's Optimization guide describes most of the required specifications per architectural generation (you didn't specify which i7 you have, there are now several generations since Nehalem and up to Haswell). Haswell, for e.g., would have - Note that if you're building a simulator, you'll want to have as many of these feature as possible

I understand the part of the paper where they trick the CPU to speculatively load the part of the victim memory into the CPU cache. Part I do not understand is how they retrieve it from cache. They don't retrieve it directly (out of bounds read bytes are not "retired" by the CPU and cannot be seen by the attacker in the attack). A vector of attack is to do the "retrieval" a bit at a time. After the CPU cache has been prepared (flushing the cache where it has to be), and has been "taught" that a if branch goes through while the condition relies on non-cached data, the CPU speculatively executes

As far as I understood it, BigInts are usually implemented in most programming languages as arrays containing digits, where, eg.: when adding two of them, each digit is added one after another like we know it from school, e.g.: 246 816 * * ---- 1062 Where * marks that there was an overflow. I learned it this way at school and all BigInt adding functions I've implemented work similar to the example above. So we all know that our processors can only natively manage ints from 0 to 2^32 / 2^64 . That means that most scripting languages in order to be high-level and offer arithmetics with big

The Intel 64 and IA-32 Architectures Software Developer's Manual says the following about re-ordering of actions by a single processor (Section 8.2.2, "Memory Ordering in P6 and More Recent Processor Families"): Reads may be reordered with older writes to different locations but not with older writes to the same location. Then below when discussing points where this is relaxed compared to earlier processors, it says: Store-buffer forwarding, when a read passes a write to the same memory location. As far as I can tell, "store-buffer forwarding" isn't precisely defined anywhere (and neither is

I'm looking to build a VM into a game and was wondering if anyone knew of any really simple VM's (I was thinking RISC/PIC was close to what I wanted) that are usually used for embedded projects such as controlling robots, motors, sensors, etc. My main concern is having to write a compiler/assembler if I roll my own. I'd be nice to use the tools that are already out there or in its simplest form just a C compiler that can compile for it :-p. I really don't want to re-invent the wheel here but I also need thousands of these running around a virtual world so they have to be as simple and as fast