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Amulet(religion, spiritualism, and occult)
An amulet is a consecrated object used for protection, for good fortune, luck, health, to attract, or to repel. It is a natural object, as opposed to a talisman, which, while used for much the same purposes, is a human-made object. C. Nelson Stewart (Man, Myth and Magic) likens a talisman to a sword and an amulet to a shield, saying the former is a reinforcer while the latter is a protector. Certainly amulets are primarily preventive, while talismans are transmitters.
Although amulets are frequently made and used by Witches, they are not exclusively so. They and talismans are a part of the larger world of magic and can be utilized by magicians who are not necessarily Witches.
Although amulets are basically natural objects—amber is an excellent example—they may be modified by carving or inscribing, or used in conjunction with other amulets and/or talismans. Most users will consecrate an amulet before using it, but others feel that the very essence of the amulet is that it is natural and therefore requires no consecration. An example of these two schools of thought may be found in the mandrake root. The mandrake naturally grows in the shape of a human figure. For this reason it was thought to have great magical properties, especially to heal and protect. Yet the more similar to a human being the mandrake appeared, the greater was the magical power it was believed to possess. For this reason it was permissible to carve the root to make it more lifelike and more powerful.
Another example of an amulet is a stone with a hole through it, known variously as a Witch Stone, a Goddess Stone, or a Hag Stone. This may be slipped onto a piece of cord or leather thong and worn around the neck for protection. Some would first cleanse the stone in salt and water and hold it in the smoke of incense, at the same time requesting from the gods that it protect its wearer. This act of consecration made the stone amulet even more powerful.
In Africa, elephant hairs are commonly used as an amulet, as are a lion's teeth or claws. Elephant hair is frequently woven into a bracelet, for ease of wearing. In Europe and America, a rabbit's foot is perhaps the most common amulet, worn or carried for good luck.
There is a doctrine of correspondences, or "doctrine of signatures," associated with amulets. This is a belief that there is a magical connection between things which look alike, and things that have at one time been connected but that are now separate. Consequently, a bear claw might be carried to give its owner the strength and fearlessness of a bear, or a monkey's paw might be carried to bestow agility. A hag stone might be thought to aid in childbirth, because of its similarity to the female vagina. A piece of iron (a horseshoe nail, for example) might be believed to give its owner strength.
Among Scottish Witches the acorn is a popular amulet, symbolizing strength and protection. It may be carried in the pocket, or a Witch may make a necklace of strung acorns. Plants, or plant parts such as seeds, pieces of wood, or nuts and berries, are used universally as amulets. A four-leaf clover is a popular example.
The circumstances under which an amulet is found can have great bearing on its significance and importance. For example, if a climber found a feather at the foot of a mountain, it would behoove the finder to carry the feather with him or her to the top of the mountain, since the feather symbolizes the ability to rise. That particular feather would be a very potent amulet in that instance.
Certain items, although not natural in the sense of not having been manufactured, may still be regarded as amulets, rather than talismans, based on the circumstances in which they are found. For example, finding an old key at a time when one is wishing to gain access to something—be it a building, a new job, or even a marriage—would be regarded as fortuitous in that the key symbolizes access. The key should be carried or worn until the goal is achieved.
an object superstitiously credited with the power to protect its owner from misfortunes, illness, and “evil spells.” Belief in the power of amulets arose in connection with primitive magic and fetishism but has lasted until our day as a vestige in many countries. Even the Christian Church, while condemning superstitions, continues to use amulets in the form of crosses and medallions worn on the body supposedly to protect believers from “dark powers.”
Work was begun at the end of 1990 and the design despatched for fabrication in February 1993. The primary intent was to demonstrate that an asynchronous microprocessor can consume less power than a synchronous design.
The design incorporates a number of concurrent units which cooperate to give instruction level compatibility with the existing synchronous part. These include an Address unit, which autonomously generates instruction fetch requests and interleaves (nondeterministically) data requests from the Execution unit; a Register file which supplies operands, queues write destinations and handles data dependencies; an Execution unit which includes a multiplier, a shifter and an ALU with data-dependent delay; a Data interface which performs byte extraction and alignment and includes an instruction prefetch buffer, and a control path which performs instruction decode. These units only synchronise to exchange data.
The design demonstrates that all the usual problems of processor design can be solved in this asynchronous framework: backward instruction set compatibility, interrupts and exact exceptions for memory faults are all covered. It also demonstrates some unusual behaviour, for instance nondeterministic prefetch depth beyond a branch instruction (though the instructions which actually get executed are, of course, deterministic). There are some unusual problems for compiler optimisation, as the metric which must be used to compare alternative code sequences is continuous rather than discrete, and the nondeterminism in external behaviour must also be taken into account.
The chip was designed using a mixture of custom datapath and compiled control logic elements, as was the synchronous ARM. The fabrication technology is the same as that used for one version of the synchronous part, reducing the number of variables when comparing the two parts.
Two silicon implementations have been received and preliminary measurements have been taken from these. The first is a 0.7um process and has achieved about 28 kDhrystones running the standard benchmark program. The other is a 1 um implementation and achieves about 20 kDhrystones. For the faster of the parts this is equivalent to a synchronous ARM6 clocked at around 20MHz; in the case of AMULET1 it is likely that this speed is limited by the memory system cycle time (just over 50ns) rather than the processor chip itself.
A fair comparison of devices at the same geometries gives the AMULET1 performance as about 70% of that of an ARM6 running at 20MHz. Its power consumption is very similar to that of the ARM6; the AMULET1 therefore delivers about 80 MIPS/W (compared with around 120 from a 20MHz ARM6). Multiplication is several times faster on the AMULET1 owing to the inclusion of a specialised asynchronous multiplier. This performance is reasonable considering that the AMULET1 is a first generation part, whereas the synchronous ARM has undergone several design iterations. AMULET2 (currently under development) is expected to be three times faster than AMULET1 - 120 kdhrystones - and use less power.
The macrocell size (without pad ring) is 5.5 mm by 4.5 mm on a 1 micron CMOS process, which is about twice the area of the synchronous part. Some of the increase can be attributed to the more sophisticated organisation of the new part: it has a deeper pipeline than the clocked version and it supports multiple outstanding memory requests; there is also specialised circuitry to increase the multiplication speed. Although there is undoubtedly some overhead attributable to the asynchronous control logic, this is estimated to be closer to 20% than to the 100% suggested by the direct comparison.
AMULET1 is code compatible with ARM6 and is so is capable of running existing binaries without modification. The implementation also includes features such as interrupts and memory aborts.
The work was part of a broad ESPRIT funded investigation into low-power technologies within the European Open Microprocessor systems Initiative (OMI) programme, where there is interest in low-power techniques both for portable equipment and (in the longer term) to alleviate the problems of the increasingly high dissipation of high-performance chips. This initial investigation into the role asynchronous logic might play has now demonstrated that asynchronous techniques can be applied to problems of the scale of a complete microprocessor.