132 lines
3.1 KiB
Plaintext
132 lines
3.1 KiB
Plaintext
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digraph heron {
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//node [shape=circle,regular=1,style=filled,fillcolor=white];
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edge [arrowhead=odot];
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graph [overlap=false];
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subgraph {
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edge [weight=3];
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C0 -> C1 -> C2 -> C3 -> C4 -> C5 -> C6 -> C7 -> C8 -> C9
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}
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// variables & constants
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mem_0 [label="mem[0]"];
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mem_i [label="mem[i]"];
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mem_i2 [label="mem[i]"];
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i [ ];
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1 [ ];
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"1a" [label="1" ];
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"1b" [label="1" ];
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"1c" [label="1" ];
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"1d" [label="1" ];
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Finish [label="Finish"];
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// operands
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s_shift_1 [label=">>",];
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i_lte_mem_0 [label=">=",];
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// i <= mem[0]
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mem_0 -> i_lte_mem_0;
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i -> i_lte_mem_0;
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{ rank=same; C1; i_lte_mem_0; }
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{ rank=same; C0; i; mem_0;}
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// if (i <= mem[0]) ->
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i_lte_mem_0 -> mem_s_gte_1 [style=dotted, arrowhead=normal,label="True",lhead=cluster_i_lte_mem_0];
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// else
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i_lte_mem_0 -> Finish [style=dotted, arrowhead=normal,label="False",lhead=cluster_i_lte_mem_0];
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{ rank=same; C9; Finish;}
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subgraph i_lte_mem_0 {
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mem_s_gte_1 [label=">"];
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s_div_x [label="/",];
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new_x [label="+",];
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s_div_x_shift_1 [label=">>",];
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x_shift_1 [label=">>",];
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old_x_lte_new_x [label="¹>=",];
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inc_i [label="+",];
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// (s > 1)
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mem_i -> mem_s_gte_1;
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"1d" -> mem_s_gte_1;
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{ rank=same; C2; mem_s_gte_1}
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// if (s > 1)
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mem_s_gte_1 -> s_shift_1 [style=dotted,arrowhead=normal,label="True"];
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// else
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mem_s_gte_1 -> inc_i [style=dotted,arrowhead=normal,label="False"];
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subgraph if_mem_i_gte_1 {
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// x = s >> 1
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mem_i -> s_shift_1;
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1 -> s_shift_1;
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s_shift_1 -> x;
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{ rank=same; C3; s_shift_1; x}
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// (x >> 1)
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x -> x_shift_1;
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"1a" -> x_shift_1;
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// (s/x)
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mem_i -> s_div_x;
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x -> s_div_x;
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{ rank=same; C4; x_shift_1; s_div_x}
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// ((s/x) >> 1)
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s_div_x -> s_div_x_shift_1;
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"1b" -> s_div_x_shift_1;
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{ rank=same; C5; s_div_x_shift_1}
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// (x >> 1) + ((s/x) >> 1);
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x_shift_1 -> new_x;
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s_div_x_shift_1 -> new_x;
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{ rank=same; C6; new_x;}
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// (old_x <= X)
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x -> old_x_lte_new_x;
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new_x -> old_x_lte_new_x;
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new_x -> x [style=dotted,label="if(¹)"];
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{ rank=same; C7; old_x_lte_new_x;}
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// if (old_x <= X)
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old_x_lte_new_x -> inc_i [style=dotted,arrowhead=normal,label="True"];
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// else
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"1c" -> inc_i;
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i -> inc_i:ne;
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inc_i:s -> i:s;
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new_x -> mem_i2 [label="if(¹)", style=dotted];
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{ rank=same; C8; inc_i; mem_i2};
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}
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}
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}
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// Listing
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// void heron_sqrt(u32 *mem) {
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// int i;
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// for (i = 1; i <= mem[0]; i++){
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// u32 s = mem[i];
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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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// u32 x = s >> 1;
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// u32 old_x = x;
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//
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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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// mem[i] = 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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// mem[i] = x;
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// }
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// }
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//}
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