31 lines
586 B
C
31 lines
586 B
C
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typedef uint32_t u32;
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// have to a multiply of 2
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#define COMMA 8 @\label{comma}@
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#define COMMA_FIX (COMMA >> 1)
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void heron_sqrt(u32 *mem) {
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int i = mem[0];
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while (i > 0) {
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u32 s = mem[i];
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u32 x = s;
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if (s > 1) {
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// x_0 = (s + 1) / 2
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// without increment to avoid overflow for 0xffffffff
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x = x >> 1;
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u32 old_x = x;
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while(1) {
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// x_{n + 1} = (x_n + (s / x_n)) / 2
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x = (x >> 1) + ((s/x) >> 1);
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if (old_x <= x) {
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break;
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}
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old_x = x;
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}
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}
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mem[i] = x << COMMA_FIX;
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i--;
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}
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}
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