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The Lounge What is on Your Mind? Can assembly language be dispensed with ? Post 302661095 by bakunin on Sunday 24th of June 2012 06:54:52 PM
Old 06-24-2012
I started my career back in the late seventies and on IBM mainframes there was either COBOL or assembler - with the 2.5 KB real memory my first system (already outdated at that time) had the choice was quite clear: learn assembler and every dirty trick there was to save some bits here, some cycles there ....

Later, in the eighties, i wrote software for DSPs and embedded systems, mainly the DSPs of Analog Devices and the Motorola 56k-series. Again, it was assembler to the fullest extent: when you write the internal software for a telephone switchboard and the company wants to sell a few millions the only thing that counts is: how many cycles did you use for that task? The lower cycles, the lower the clock rates could be, which means you can buy lower graded CPUs, which cost exponentially less which means a BIG difference in customer price. If you could save one arithmetic unit or one register, the custom-built processors could be built without these parts which made them cheaper too.

We used to beat optimizing compilers by a very large margin. OK, we couldn't decipher our own code three months after "tape-out" (the tasks got simulated on an ICE and finally the tape with the processor specification was sent to the provider of the DSPs to be built on order), but it was expected to write the next version from scratch anyway.

One of my first jobs on a PC was to write a DOS device driver for a specialized file system for the real-time storage of acoustic data. This was the time of MFM-disks and the data rate for a usual 16-bit sampling in stereo frequency (44.1 kHz) is just a tad below the bandwidth of the ST-506 interface. My driver had to use every ounce of bandwidth it could get just keep up. Mind you, we had one of the brand-new hot 16 MHz NEAT 286, an extremely fast system!

Sure, these are extremes. But ones uses assembly language for the same reason we used to use assembly throughout computing history: for its unparalleled speed and for the sheer control it gives you over the system and its hardware. C is a language nicely suited for rapid prototyping, but i'm still quite confident to be able to beat any C-compiler in terms of speed of execution with hand-crafted assembler code. Even with all those nifty optimizations switched on.

This is nothing to say against C - in fact i like C. But to really understand what C is about you have to have experienced the problems solved/avoided by its use. You have to have been at the very bottom at least once to appreciate being on top. And, who knows, you might even start to like being at the source of things.

bakunin
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Mono(permview)															    Mono(permview)

NAME
permview - Viewer for declarative security permission sets inside assemblies. SYNOPSIS
permview [options] assembly DESCRIPTION
This tools allow to list the declarative security attributes present in an assembly. The security attributes are either found on the assem- bly level, on the classes and the methods. This tool is useful to diagnose why an assembly won't load or why some class/method throws Secu- rityException. OPTIONS
-output filename Output all declarative security attributes related informations into the specified file. -xml | --xml | /XML Output all declarative security attributes in an XML format. -decl | --decl | /DECL Show declarative security attributes on classes and methods. The default, without the -decl option, is to show only the assembly level permission sets. -? | /? | -h[elp] | /h[elp] Display help informations about the permview tool. EXAMPLES
permview mscorlib.dll This will show the minimum, optional and refused permissions sets (i.e. the assembly level security actions) that are compiled inside the mscorlib assembly. permview -decl permview.exe This will show all (assembly, class or method level) declarative security attributes present in the permview.exe assembly. AUTHOR
Written by Sebastien Pouliot COPYRIGHT
Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com) MAILING LISTS
Visit http://lists.ximian.com/mailman/listinfo/mono-devel-list for details. WEB SITE
Visit http://www.mono-project.com for details Mono(permview)
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