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29 lines
787 B
29 lines
787 B
/*
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* The application of lab2_3.
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*/
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#include "user_lib.h"
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#include "util/types.h"
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//
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// compute the summation of an arithmetic sequence. for a given "n", compute
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// result = n + (n-1) + (n-2) + ... + 0
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// sum_sequence() calls itself recursively till 0. The recursive call, however,
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// may consume more memory (from stack) than a physical 4KB page, leading to a page fault.
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// PKE kernel needs to improved to handle such page fault by expanding the stack.
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//
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uint64 sum_sequence(uint64 n) {
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if (n == 0)
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return 0;
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else
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return sum_sequence( n-1 ) + n;
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}
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int main(void) {
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// we need a large enough "n" to trigger pagefaults in the user stack
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uint64 n = 1000;
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printu("Summation of an arithmetic sequence from 0 to %ld is: %ld \n", n, sum_sequence(1000) );
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exit(0);
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}
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