My projects

I write soft­ware mostly for Mor­phOS and Ami­gaOS, (clas­sic Ami­gaOS 3.x). I've also done a few small ap­pli­ca­tions for Win­dows. My pro­gram­ming lan­guage of choice is C, I also have writ­ten code in C++, Lua, Amiga E and PHP, as well as M68k and PowePC as­sem­bler.

• Di­gi­Booster 3, music tracker for Mor­phOS and Ami­gaOS
• Prometheus PCI, my most ad­vanced hard­ware pro­ject
• Reg­gae, media pro­cess­ing frame­work for Mor­phOS
• Mor­phOS Pro­gram­mer's Hand­book, an e-book about Mor­phOS pro­gram­ming.
• Small hardware projects for classic Amigas.

Small applications and tools

• Ap­pend­Date, a ver­sa­tile shell tool for adding dates to file­names.
• Au­dioTo­Clip, shell tool for plac­ing audio files in the sys­tem clip­board.
• Date­Calc, date cal­cu­la­tor using pro­lep­tic gre­go­rian cal­en­dar.
• Di­giRoller, a stand­alone Di­gi­Booster mod­ule player and ren­derer.
• Fla­cochlo­rine, FLAC stream val­ida­tor and an­a­lyzer.
• Gam­maMe­ter, mon­i­tor gamma co­ef­fi­cient mea­sure­ment tool.
• Lua Ex­plo­rador, source level de­bug­ger for Lua.
• Mul­ti­Play, com­man­d­line gap­less audio player.
• Su­dom­i­na­tor, su­doku solver and hin­ter.
• U1Synth, sim­ple audio syn­the­sizer.
• Zgrzy­tor, gen­er­a­tor of pseudonoise audio waves using LFSR reg­is­ter.
• Zor­manita, audio for­mat con­verter and proces­sor.

My articles

• Amiga Icon File For­mat, de­tailed de­scrip­tion of Amiga .info files in­ter­nals. The ar­ti­cle con­cen­trates on de­cod­ing icon im­ages and con­vert­ing them to RGB. Stan­dard Amiga icon color palettes are also spec­i­fied.
• String To Float­ing Point Num­ber Con­ver­sion, shows how to con­vert a tex­tual rep­re­sen­ta­tion of a float­ing point num­ber (in plain or sci­en­tific no­ta­tion) into a num­ber bi­nary con­form­ing to IEEE754. The code is al­most a drop-in re­place­ment for stan­dard atof() and str­tod() func­tions. It does not use the stan­dard C li­brary how­ever and is also much shorter.
• Notes on AES-256 Ci­pher Im­ple­men­ta­tion on Pow­erPC Proces­sors, my at­tempt to code an op­ti­mized im­ple­men­ta­tion of this well known crypto­graphic stan­dard for PPC proces­sors. I show the op­ti­miza­tion process step by step, start­ing from naive byte­wise im­ple­men­ta­tion, through op­ti­miza­tion in C, using as­sem­bler and fi­nally Al­tiVec. Cur­rently this ar­ti­cle is work in progress.

Peer-reviewed scientific publications

I've writ­ten them until given up my aca­d­e­mic ca­reer. Most of them is re­lated to dig­i­tal sig­nal pro­cess­ing, es­pe­cially using Al­tiVec SIMD unit of Pow­erPC proces­sors.

• Mul­ti­stan­dard codec of speech sig­nals based on mod­i­fied TM­S320C5x DSK, Griszin J., Konopko K., Kraszewski G., Zankiewicz A. (1998). Pub­lished when I was an un­der­grad­u­ated stu­dent, on the Sec­ond Eu­ro­pean DSP Ed­u­ca­tion and Re­search Con­fer­ence in Paris (23, 24 Sep 1998). Closely re­lated to my M. Sc. the­sis.
• Re­al­time speech GSM codec on TM­S320C50 DSP proces­sor, Kraszewski G. (1999). Pub­lished on SECON'99 con­fer­ence, which took place on Mil­i­tary Uni­ver­sity of Tech­nol­ogy in War­saw, 16, 17 Nov 1999. Writ­ten just after I've de­fended my M. Sc. the­sis. In the paper I've de­scribed in de­tails my GSM 6.10 speech com­pres­sion codec im­ple­men­ta­tion on Texas In­stru­ments TM­S320C50 dig­i­tal sig­nal proces­sor.
• A codec of speech based on the en­hanced TM­S320C5x DSK mod­ule, Konopko K., Kraszewski G. (1999). This paper de­scribes an in­ter­face, de­vel­oped by me in co­op­er­a­tion with K. Konopko. The in­ter­face con­nected a DSK mod­ule with TM­S320C50 proces­sor with a PC com­puter. It con­sisted of DSK in­ter­face board de­signed by me and an ISA card de­vel­oped by Mr. Konopko. He also wrote comm­ni­ca­tion soft­ware run­ning on Win­dows. We pub­lished the paper on 99' Sig­nal Pro­cess­ing Work­shop in Poz­nań (8 Oct 1999).
• PCI bus bridge for MC 680x0 based com­puter sys­tem using PLD tech­nol­ogy, Kraszewski G. (2003). The paper de­scribes the "Prometheus" PCI bridge­board for Amiga 3000/4000 com­put­ers. It is a bridge in­ter­con­nect­ing asyn­chro­nous Amiga Zorro III ex­ten­sion bus with stan­dard PCI bus. It was de­signed using two MAX7128 PLD chips from Al­tera. It al­lowed for using sev­eral mod­els of PCI cards in Amiga com­put­ers. The paper was pre­sented on XII IEEE-SPIE Sym­po­sium on Pho­ton­ics and Web En­gi­neer­ing, held in Wilga near War­saw, on 22 to 25 May 2003. Then it has been pub­lished in Pro­ceed­ings of SPIE in 2004.
• Non-uni­form ker­nel sam­pling in audio sig­nal re­sam­pler, Kraszewski G. (2005). This is my first paper on using Al­tiVec SIMD unit for dig­i­tal sig­nal pro­cess­ing. I've in­ves­ti­gated a pos­si­bil­ity to lower the size of the sinc() ker­nel table for an audio re­sam­pler with­out de­creas­ing re­sam­pled audio qual­ity. Pub­lished on Sig­nal Pro­cess­ing 2005 Con­fer­ence or­ga­nized by IEEE in Poz­nan, 30 Oct 2005.
• Fast FIR fil­ters for SIMD proces­sors with lim­ited mem­ory band­width, Kraszewski G. (2006). The paper demon­strates how re­or­ga­ni­za­tion of order of com­pu­ta­tions in a FIR fil­ter can in­crease com­pu­ta­tional ef­fi­ciency with­out re­duc­ing the num­ber of arith­metic op­er­a­tions. As a FIR fil­ter is usu­ally a mem­ory bound task for a SIMD proces­sor, low­er­ing num­ber of mem­ory ac­cesses per out­put sam­ple in­creases the speed of pro­cess­ing. I've pub­lished a the­ory be­hind it, as well as re­sults of prac­ti­cal ex­per­i­ments. Pre­sented on XI AES Sym­po­sium: New Trends in Audio and Video held on Białystok Uni­ver­sity of Tech­nol­ogy (20 to 22 Sep 2006).
• Per­for­mance analy­sis of al­ter­na­tive struc­tures for 16-bit in­te­ger FIR fil­ter im­ple­mented on Al­tiVec SIMD pro­cess­ing unit, Kraszewski G. (2006). While the pre­vi­ous paper de­scribed float­ing point FIR fil­ters, this one is a study on fixed point FIR fil­ters im­ple­mented with Al­tiVec. The­o­ret­i­cal analy­sis of 3 al­ter­na­tive struc­tures of such fil­ters is pre­sented and backed up with re­sults of bench­marks of their im­ple­men­ta­tions. Paper pre­sented on Sig­nal Pro­cess­ing Work­shop or­ga­nized by IEEE in Poz­nan, 29 Sep 2006.
• Fast im­ple­men­ta­tion of 16-bit FIR fil­ters for Al­tiVec ar­chi­tec­ture, Kraszewski G. (2007). Ex­ten­sion of the pre­vi­ous paper with new ex­per­i­men­tal re­sults. Pub­lished in Elek­tron­ika jour­nal, issue 4/2007.

Webpages I've developed and manage

In web de­vel­op­ment I be­lieve in sim­plic­ity in both graph­ics de­sign and server side pro­gram­ming. I use basic pop­u­lar web tech­nolo­gies: HTML, JavaScript, PHP, MySQL. My pro­jects are light­weight, clean and se­cure.

• morphos-files.net, the Mor­phOS soft­ware repos­i­tory. I've pro­grammed the site, I'm also the main­tainer. Graphic de­sign is mine too, ex­cept of the upper ban­ner graphic, which has been drawn by Prze­mysław Tkaczyk.
• elektrownia.pb.edu.pl, a mon­i­tor­ing site of a hy­brid power plant (wind and solar). I've also writ­ten large parts of data ac­qui­si­tion back­end.