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thumb

1. the first and usually shortest and thickest of the digits of the hand, composed of two short bones
2. the corresponding digit in other vertebrates

Thumb

(processor)
An extension to the Advanced RISC Machine architecture, announced on 06 March 1995 by Advanced RISC Machines Ltd. By identifying the critical subset of the ARM instruction set and encoding it into 16 bits, ARM has succeeded in reducing typical program size by 30-40% from ARM's already excellent code density. Since this Thumb instruction set uses less memory for program storage, cost is further reduced.

All Thumb-aware processor cores combine the capability to execute both the 32-bit ARM and the 16-bit Thumb instruction sets. Careful design of the Thumb instructions allow them to be decompressed into full ARM instructions transparently during normal instruction decoding without any performance penalty. This differs from other 32-bit processors, like the Intel 486SX, with a 16-bit data bus, which require two 16-bit memory accesses to execute every 32-bit instruction and so halve performance.

The patented Thumb decompressor has been carefully designed with only a small amount of circuitry additional to the existing instruction decoder, so chip size and thus cost do not significantly increase. Designers can easily interleave fast ARM instructions (for performance critical parts of a program) with compact Thumb code to save memory.

thumb

(jargon)
The slider or "bubble" on a window system scrollbar. So called because moving it allows you to browse through the contents of a text window in a way analogous to thumbing through a book.

thumb

(1) See scroll bar and thumb culture.

(2) (Thumb) An extension to the architecture of an ARM chip that provides enhanced code density. It stores a subset of 32-bit instructions as compressed 16-bit instructions and decompresses them back to 32 bits upon execution. See ARM chips.
References in periodicals archive ?
Perhaps the most interesting of its five chapters is A History of Picture Books' which provides a very helpful thumb-nail sketch of the way in which illustrated texts have developed over the centuries across different cultures.
After 451 pages of lively-written biographies, Losch adds an additional 122 pages that list every last individual, even those mentioned only in genealogies (he counts 28 people named Azariah), and gives a thumb-nail identification of each and a guide to the pronunciation of their name.
Their care for the poor naked, thumb-nail size infant they give birth to is an amazing achievement for a creature so sedentary and apparently slothful.
McCullough is excellent at giving thumb-nail sketches of major participants from both sides.
THE ROWS OF HUMAN, BESTIAL AND DIVINE FACES that are arranged across the dust-cover of Jaromir Malek's Egypt: 4000 Years of Art perfectly encapsulate the contents of the book: over three hundred exquisite photographs and thumb-nail descriptions of Egyptian works of art, organised in chronological order from late prehistory (c.
One could have added to the plus side the useful thumb-nail sketches of planning conditions and obligations, and design policy, were it not for the fact that the Government's position on both appears to have shifted (OK, in the case of planning obligations I mean stalled) during the passage of the Planning and Compulsory Purchase Bill.
Character-packed as it is many are merely thumb-nail sketches while those who are more fleshed out are so superficial that they must work hard to gain any sympathy.
Mr Trevor-Jones told Knutsford Crown Court,Cheshire, that Clare, who has been suspended from duty, had taken a number of thumb-nail pictures and blown them up into a collage.
Other new features include an audio chat, enhanced mapping and viewing of classroom layouts, teacher-friendly automation for distributing and collecting assignments and tests, and simultaneous thumb-nail views of all student screens.
Small thumb-nail images appear on the left side of the screen, and you can click on one to see the full text with illustrations (Figure).