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More simple C and color mixing tests

Posted 06-11-2013 at 12:30 AM by rainbowsally

Today's Feature
  • Here's another pixel (color) mixing toy. The best yet.

Back a couple of blog pages
http://www.linuxquestions.org/questi...lamping-35557/
we were playing with color mixing and data clamping and all kinds of junk including comparing routines to mix colors by a floating point ratio.

This is mixcolors.c - named the same as the other version we were playing with and...
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Old

Simple C - mix pixel data, integer math (fixed point), data clamping...

Posted 06-06-2013 at 06:15 PM by rainbowsally

Simple C to mix pixel data, integer math (fixed point), data clamping

Today's Features
  • Simple program to add two pixels clamping each byte to 0xFF, but adding all four bytes in parallel for speed. There are no branches in the algorithm.
  • Another simple program to mix two colors defining a gradient using a fraction from 0 to 1. We compare floating point to fixed point math versions.


Surprisingly, the long version compiles about the same code as the short one with...
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Old

New-Make And MC2, Meet MPG123 (terminal app to play MP3 and other file formats)

Posted 12-25-2012 at 08:11 PM by rainbowsally
Updated 08-06-2014 at 08:47 AM by rainbowsally (wrong acronym for alsa)

After that last rant about screwy software, I found some GREAT software. mpg123 is outstanding.

Today's Features
  • Me eating my words, even about assembler coding. ;-)

Famous last words galore! I even have to eat my words about asm. In fact this app is so cool I had to add the ability to compile asm and C sources in the same directory to the mc2 code.

MPG123 (sandboxed relocatable binary installation OR compile from code, modify, experiment, etc.) is linked...
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Old

ASM: mixing assembler and C++

Posted 02-05-2012 at 12:05 PM by rainbowsally
Updated 08-06-2014 at 10:30 AM by rainbowsally

This is for intel 32 bit assembler. For 64-bits the calling convention is a bit different. See previous entries (specifically asm 64 bits) if you need a leg-up to break the 64 bit barrier.

Features:
  • Asm functions that can call class functions (using an object pointer) through jump vectors written in C.
  • Usage of extern "C" declarations to un-mangle names we need to keep simple for asm coding.

[If you really want to get down, you can use the mangled names as...
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Old

ASM: Intercepting (and using) Errors (like segfaults) in asm (aka SEH)

Posted 02-03-2012 at 04:10 PM by rainbowsally

This is for i86 and x86_64 types but with a bit of poking around you can probably find a similar way to do this with other CPUs.

Note: This asm requires 'sigaction'. (See the test code. And bear in mind that this is not an attempt to create a full-blown system of signal handlers. Check the libc docs for 'sigaction' for ideas on how you can use something like this for a seed for a more extensive application.)

There used to be a lot of cool little programs for the...
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