52 lines
1.6 KiB
Plaintext
52 lines
1.6 KiB
Plaintext
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Name:
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=====
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prime
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Description:
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============
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Example that displays the timer count on the LEDs.
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Purpose:
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========
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This example consists of a non-optimized, brute-force routine for computing
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the number of prime numbers between 1 and a given value, N. The routine
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uses modulo operations to determine whether a value is prime or not. While
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obviously not optimal, it is very useful for exercising the core.
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For this example, N is 100000, for which the answer is 9592.
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For Apollo3 at 48MHz, the time to compute the answer for Keil and IAR:
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IAR v8.11.1: 1:43.
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Keil ARMCC 4060528: 1:55.
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Printing takes place over the ITM at 1M Baud.
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Additional Information:
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=======================
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The goal of this example is to measure current consumption while the core
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is working to compute the answer. Power and energy can then be derived
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knowing the current and run time.
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The example prints an initial banner to the UART port. After each prime
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loop, it enables the UART long enough to print the answer, disables the
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UART and starts the computation again.
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Text is output to the UART at 115,200 BAUD, 8 bit, no parity.
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Please note that text end-of-line is a newline (LF) character only.
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Therefore, the UART terminal must be set to simulate a CR/LF.
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Note: For minimum power, disable the printing by setting PRINT_UART to 0.
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The prime_number() routine is open source and is used here under the
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GNU LESSER GENERAL PUBLIC LICENSE Version 3, 29 June 2007. Details,
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documentation, and the full license for this routine can be found in
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the third_party/prime_mpi/ directory of the SDK.
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******************************************************************************
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