embedded

Quick question for you guys, in my loop I need to use CMP , BLT and BGT to compare some values. How would use said instructions in the following loop? I'm trying to use BGT , BLT and CMP as I need them to make my application work. The trouble is I have no idea how to use them. If I wanted to use CMP to compare r6, with r4 and put the difference into r7, how would I do this? The same question if I wanted to use BLT if r7 is less than 0, how would I do this? BGT ??????? ; branch if greater than 5 CMP ???????? ; compare r6 with r4 , put difference into r7 BLT ???????? ;branch if r7 is less than 0

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There appears to be no definitive standardized stack frame and C language calling conventions (register usage and such) for the MIPS-32 Processor Architecture. That is, it appears to be completely up to the assembler/compiler tool chain to define their own stack frame and calling conventions. I've struggled to find a definitive reference of what conventions the GCC compiler uses for MIPS-32 instruction set. I'm specially using GCC cross-compiler on Cygwin that targets a MIPS-32 core being used in an embedded environment on the eCos open source kernel. Any references to definitive documentation

I am sampling a sine wave at 48 kHz, the frequency range of my sine wave can vary from 0 to 20000 Hz with a step of about 100 Hz. I am using a lookup table approach. So I generate 4096 samples for a sine wave for 4096 different phases. I think the general idea behind this to increment the step size and use different step sizes for different frequncy. So I do the following (pseudo code). But I am not sure how the step size is going to be related to the frequency I want to generate the samples of the sine wave of? For example if my frequency is 15000 Hz what would be the step size that I have to

I am a embedded developer and use volatile keyword when working with I/O ports. But my Project manager suggested using volatile keyword is harmful and has lot of draw backs, But i find in most of the cases volatile is useful in embedded programming, As per my knowledge volatile is harmful in kernel code as the changes to our code will become unpredictable. There are any drawbacks using volatile in Embedded Systems also? No, volatile is not harmful. In any situation. Ever. There is no possible well-formed piece of code that will break with the addition of volatile to an object (and pointers to

For consistency with other platforms, I need to use signed char in some native code I'm working on. But by default on Android NDK char type is unsigned . I have tried to explicitly use signed char type but it generates too many warnings differ in signedness when string constant/library functions are involved, so I'm looking to build my code with -fsigned-char . I'm now trying to anticipate problems regarding Android ARM ABI and API when -fsigned-char is used, but I can't find any problem yet. In Procedure Call Standard for the ARM Architecture ABI (AAPCS) , 7.1.1 Arithmetic Types, and C

I am working with a multithreaded embedded application. Each thread is allocated stack sizes based on its functionality. Recently we found that one of the thread corrupted the stack by defining a array of local variables that was more than the stack size. The OS is uItron. My solution, I registered a timer for 10 mS, and this timer will check for stack corruption. Stack corruption checking method, 1. Initialize the stack memory with some unique pattern (I use 0x5A5A5A5A) 2. Check from the time if top of the stack memory is still 0x5A5A5A5A My question, Is there a better way to check this type

I'd like to use a Regex parser to aid in some string processing in a C application. I'm ideally looking for something lightweight and open-source. The target platform is an embedded system so we're looking to save as much as possible with memory consumption in particular. I've found a number of options online but was wondering if anyone can make additional suggestions that may help in this particular context. Many thanks, Scintilla , an open source text editor component, uses Ozan S. Yigit's RE engine It was chosen because it is in the public domain (so no encumbering license) and very