37 lines
1.8 KiB
C
37 lines
1.8 KiB
C
#define EXPAND_2_INNER_CASES(i, x, y) INNER_CASE(i, x, y); INNER_CASE(i + 1, x, y);
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#define EXPAND_4_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i + 2, x, y)
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#define EXPAND_8_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i + 4, x, y)
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#define EXPAND_16_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i + 8, x, y)
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#define EXPAND_32_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i + 16, x, y)
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#define EXPAND_64_INNER_CASES(i, x, y) EXPAND_32_INNER_CASES(i, x, y) EXPAND_32_INNER_CASES(i + 32, x, y)
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#define EXPAND_2_OUTER_CASES(i, x, y) OUTER_CASE(i, x, y); OUTER_CASE(i + 1, x, y);
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#define EXPAND_4_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i + 2, x, y)
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#define EXPAND_8_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i + 4, x, y)
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#define EXPAND_16_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i + 8, x, y)
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#define EXPAND_32_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i + 16, x, y)
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#define EXPAND_64_OUTER_CASES(i, x, y) EXPAND_32_OUTER_CASES(i, x, y) EXPAND_32_OUTER_CASES(i + 32, x, y)
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// Rather than a single monstrous fan-out, this fans out in smaller increments,
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// but to a similar size.
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unsigned cfg_nested_switch(int x) {
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unsigned y = 0;
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while (x > 0) {
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switch (x) {
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#define INNER_CASE(i, x, y) \
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case i: { int case_var = 3*x + i; y += case_var - 1; break; }
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#define OUTER_CASE(i, x, y) \
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case i: { \
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int case_var = y >> 8; \
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switch (case_var) { \
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EXPAND_64_INNER_CASES(0, x, y); \
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} \
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break; \
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}
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EXPAND_64_OUTER_CASES(0, x, y);
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}
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--x;
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}
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return y;
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}
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