All current processors are using branch prediction in order to better exploit the pipeline. Branch prediction is based on limited size tables and thus several branches are sharing the same entry which is made of a simple 2-bit counter. This is called aliasing. Aliased branch predictors are subject to destructive interferences and removing them by the addition of a tag identifying precisely a branch to a 2-bit counter is prohibitive. An entry of our prediction table is made of several counters which predict a sequence of consecutive correlated branches and not only one. Thus, a tag can be added to an entry at a lower cost since the tag is shared by several branches. Each time a sequence is retrieved in the prediction table, it provides several predictions. An annex tagless predictor is solicited when a sequence is not found in the sequence table. Collisions are avoided in the sequence table but, to achieve a misprediction rate as low as the one of the current uptodate predictors, several tables should be used, each table being indexed through a different branch history length. Among the predictions provided by the sequences, a priority mechanism selects the most accurate i.e. the one provided by the table with the longest history. Finally, having tagged entries allows us to implement an intelligent system that dynamically adapts the branch history lengths according to the applications.
A Way to Reduce Aliasing in Branch Prediction Tables
T. Haquin, C. Rochange and P. Sainrat
Vladimir I. Oliker
In this paper the problem of synthesis of offset shaped single reflector antenna is considered. This problem has to be solved when a reflector antenna system is required to control the field amplitude and/or phase on the far-field or on the output aperture in the near-field. Achieving high efficiency is a very important objective of the design and shaped reflector antennas are used for that purpose.
The equations of the problem are strongly nonlinear partial differential equations which can not be analyzed by standard techniques. Though the problem has been the subject of study by many authors for over 40 years, up until recently, there were no rigorous theoretical results resolving completely the questions of existence and uniqueness. With few exceptions, authors have attacked the problem with heuristic numerical procedures, and, depending on the specific formulation, obtained different results not always in agreement with each other.
In this paper a new method for solving the single reflector problem is presented. The new method allows a complete and mathematically rigorous investigation of this problem. Furthermore, the proposed method lends itself to a numerical implementation and we present here several examples.
Das, Dash and Kamila
Department of Mathematics, College of Engineering and Technology, OUAT, Bhubaneswar-751003, Orissa, India Received 23 June 2000 Abstract —The ow of a viscous incompressible and electrically conducting uid between two stretched/ squeezed horizontal porous plates subject to uniform injection at the upper
Wen, Bradean, Russell, Pourmohammadi, Harris and Ingham
results of Eqns (1)–(5) subject to the boundary conditions (9)–(23). The discretisation of the solution domain D is chosen to be uniform in the x and y directions, but with different grid systems for the velocity components u and v and the pressure p . The grid points for the turbulent kinetic energy, k
Theoretical Background Studies of mathematics usually focus on the varied problems which arise at school. These problems range from differences between boys and girls regarding academic attainments from reasons for failing in this subject ( Fennema & Franke, 1992 ; Maqsud, 1997 ) and up to diversified
complex subject. The way of teaching mathematics, though, using uninteresting text books and with not the best qualified teachers, turns learning into a traumatic experience for many pupils. The mathematician, philosopher and sociologist, Bertrand Russell, wrote that mathematics is a subject whereby no
Dorit Patkin and Ruthi Barkai
between the subjects. Another characteristic of the van Hieles’ theory is that unlike other learning theories, particularly that of Piaget (1969) , their theory is grounded in the assumption that moving from one thinking level to another depends on teaching or learning experiences rather than on age or
Elementary School Mathematics Teachers’ Features of Education, Knowledge, Teaching and Personality
Edited by Dorit Patkin and Avikam Gazit
Eti Gilad and Shosh Millet
students he interviewed attributed the greatest importance to external factors (e.g. lack of other options of learning subjects, influence of others, wages, stable occupation and convenient hours). Moreover, Seng Yong (1995) points out that, … the motives for choosing the teaching profession are greatly
Dorit Patkin and Avikam Gazit
transcend text and workbook activities to include activities such as songs, games, simulations, and projects. They also appreciate teachers who spark love for the subject matter by capitalizing on students’ outside interests and students’ preferences for enjoyable, engaging activities ( Guillaume & Kirtman