Kenji Kitagawa

A Hardware Accelerator for Java TM Platforms on a 130-nm Embedded Processor Core

We have developed a hardware accelerator for Java platforms, integrated on a SuperH microprocessor core, using a 130-nm CMOS process. The Java accelerator, a bytecode translation unit (BTU), is tightly coupled with the CPU to share resources. The BTU supports 159 basic bytecodes and 5 or 6 optional bytecodes. It. supports both connected device configuration (CDC) 1.0 and connected limited device configuration (CLDC) 1.0.4 technologies. The BTU corresponds to the dual-issued superscalar CPU and applies a new method, control-sharing. With this method, the BTU always grasps the pipeline status of the CPU, and the Java program is processed by both the BTU and the CPU. To implement this method, we developed some acceleration techniques: fast branch requests, enhanced CPU instructions, Java runtime exception detection hardware, and fewer overhead cycles of handover between the BTU and the CPU. In particular, the BTU can detect Java runtime exceptions in parallel with other processing, such as an array access. With previous methods, there is a disadvantage in that CPU efficiency decreases for Java-specific processing, such as array index bounds checking. The sample chip was fabricated in Renesas 130-nm, five-layer Cu, dual-vth -low-power CMOS technology. The chip runs at 216 MHz and 1.2 V. The BTU has 75 kG. The benchmark on an evaluation board showed 6.55 embedded caffeine marks (ECM)/MH/. on the CLDC 1.0.4 configuration, a tenfold speed increase without the BTU for roughly the same power consumption. In other words, power savings of 90 percent with the same performance were achieved.

Some barium getter problems on the vacuum tubes

Abstract The writers have carried out experiments on the action and behaviour of getters as used in the actual production of, for example, receiving tubes, power tubes, cathode ray tubes, mercury rectifiers and X-ray tubes. Initially the results obtained from the study of the flashing conditions of the getter and the effect of these conditions on the sorption of gases are presented. Results are given for the quantity of the gas sorbed during the first minute, the following four minutes and the successive 10 min, for getters which have been evaporated for 10 and 60 sec. The difference in the quantity of gas initially sorbed when using different times of flashing are quite remarkable in the case of N2 and H2. Due to this the quantity of gas sorbed can nearly be doubled by a rapid firing of the getter. This difference is less marked for O2 and negligibly small for CO and CO2. Similar studies have been made using rare gases; these studies have been helped by using the electron microscope to study the surface of the getter film. Studies have also been made on the influence of the distance between getter and condensing wall and hence of the condensing area of barium film. By examining cathode ray tubes, the dependance of the tube pressure and life on the conditions of flashing of the getter have been studied. In non aluminized picture tubes data are presented giving the most favourable angle of connection of the getter assembly to the electron gun. The modifications made to the cathode structure of X-ray tubes in order to obtain the most favourable conditions when using the getter are reported. Data on the pressure obtained under such circumstances are also presented. Subsequently a study is given of the gas sorption by barium, magnesium and titanium, in mercury vapour tubes. Finally there is a study of the influence of the getter on the emission from the oxide cathodes employed in mercury rectifiers made with an apposite apparatus.