UM0304

Definitions and related documents

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processor can actually use this bit to determine if the instruction jumped to should be

executed in Thumb or ARM state:

●

If bit 0 set then execute in Thumb state

●

If bit 0 clear then execute in ARM state

Thumb was defined for two main reasons:

1.

Better code density, as the instructions are half the size of ARM instructions (although

some ARM instructions require two Thumb instructions for the same effect). You would

have to compile the application for ARM and Thumb and see what gives the best result.

2.

Better performance from narrow memory, as instruction fetches from smaller memory

(ie: 8-bit or 16-bit) will be reduced in Thumb mode.

1.3

References

1.

Sanjit K. Mitra, "Digital Signal Processing - A Computer Based Approach", McGraw

Hill, Third Edition 2006.

2.

R. Deka and J. G. Gardiner, "On the Fundamentals of Digital Signal Processing

Micros," Journal of Microcomputer Applications, Vol 17 No 1, pp 101-135, U K, January

1994.

3.

E. Oran Brigham, "The Fast Fourier Transform and its Applications", ISBN 0-13-

307547-8, Prentice-Hall International Editions, 1988.

4.

C.S. Burrus, "Unscrambling for fast DFT algorithms", IEEE Transactions on Acoustics,

Speech, and Signal Processing, ASSP-36(7), 1086-1089, July 1988.

5.

C. S. Burrus and T.W. Parks, "DFT/FFT and Convolution Algorithms - Theory and

Implementation", J. Wiley, 1985.