From: Stéphane Domas Date: Wed, 19 Oct 2011 15:20:06 +0000 (+0200) Subject: 7ème commit X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/dmems12.git/commitdiff_plain/76b46095d99d4f535bfac76daa38cf3b31a477b3 7ème commit --- diff --git a/dmems12.tex b/dmems12.tex index 3fd1ca1..647111e 100644 --- a/dmems12.tex +++ b/dmems12.tex @@ -226,10 +226,12 @@ In fact, this timing is a very hard constraint. Let consider a very small programm that initializes twenty million of doubles in memory and then does 1000000 cumulated sums on 20 contiguous values (experimental profiles have about this size). On an intel Core 2 Duo -E6650 at 2.33GHz, this program reaches an average of 155Mflops. It -implies that the phase computation algorithm should not take more than -$155\times 12.5 = 1937$ floating operations. For integers, it gives -$3000$ operations. Obviously, some cache effects and optimizations on +E6650 at 2.33GHz, this program reaches an average of 155Mflops. + +%%Itimplies that the phase computation algorithm should not take more than +%%$155\times 12.5 = 1937$ floating operations. For integers, it gives $3000$ operations. + +Obviously, some cache effects and optimizations on huge amount of computations can drastically increase these performances : peak efficiency is about 2.5Gflops for the considered CPU. But this is not the case for phase computation that used only few @@ -304,6 +306,7 @@ simultaneously. When it is possible, using a pipeline is a good solution to manipulate new data at each clock top and using parallelism to handle simultaneously several data streams. +%% parler du VHDL, synthèse et bitstream \subsection{The board} The board we use is designed by the Armadeus compagny, under the name @@ -653,15 +656,30 @@ mapping and routing the design on the Spartan6. By the way, extra-latency is generated and there must be idle times between two profiles entering into the pipeline. -Before obtaining the least bitstream, the crucial question is : how to -translate the C code the LSQ into VHDL ? +%%Before obtaining the least bitstream, the crucial question is : how to +%%translate the C code the LSQ into VHDL ? + +%\subsection{VHDL design paradigms} -\subsection{VHDL design paradigms} +\section{Experimental tests} \subsection{VHDL implementation} -\section{Experimental results} +% - ecriture d'un code en C avec integer +% - calcul de la taille max en bit de chaque variable en fonction de la quantization. +% - tests de quantization : équilibre entre précision et contraintes FPGA +% - en parallèle : simulink et VHDL à la main +% +\subsection{Simulation} + +% ghdl + gtkwave +% au mieux : une phase tous les 33 cycles, latence de 95 cycles. +% mais routage/placement impossible. +\subsection{Bitstream creation} + +% pas fait mais prévision d'une sortie tous les 480ns avec une latence de 1120 + \label{sec:results}