test/duffextensive.c

   1 void copy0 (char *to, char* from, int count)
   2 {
   3   int n = (count+7)/8;
   4   switch (count%8) do {
   5   case 0: *to = *from++;
   6   case 7: *to = *from++;
   7   case 6: *to = *from++;
   8   case 5: *to = *from++;
   9   case 4: *to = *from++;
  10   case 3: *to = *from++;
  11   case 2: *to = *from++;
  12   case 1: *to = *from++;
  13   } while (--n>0);
  14 }
  15
  16 void copy1 (char *to, char *from, int count)
  17 {
  18   int n = (count+7)/8;
  19   switch (count%8) {
  20   case 0: do {*to = *from++;
  21   case 7: *to = *from++;
  22   case 6: *to = *from++;
  23   case 5: *to = *from++;
  24   case 4: *to = *from++;
  25   case 3: *to = *from++;
  26   case 2: *to = *from++;
  27   case 1: *to = *from++;
  28   } while (--n>0);
  29   }
  30 }
  31
  32 void copy2 (char *to, char* from, int count)
  33 {
  34   int n = (count+7)/8;
  35   switch (count%8) while (n-->0) {
  36   case 0: *to = *from++;
  37   case 7: *to = *from++;
  38   case 6: *to = *from++;
  39   case 5: *to = *from++;
  40   case 4: *to = *from++;
  41   case 3: *to = *from++;
  42   case 2: *to = *from++;
  43   case 1: *to = *from++;
  44   };
  45 }
  46
  47 void copy3 (char *to, char *from, int count)
  48 {
  49   int n = (count+7)/8;
  50   switch (count%8) {
  51   case 0: while (n-->0) {*to = *from++;
  52   case 7: *to = *from++;
  53   case 6: *to = *from++;
  54   case 5: *to = *from++;
  55   case 4: *to = *from++;
  56   case 3: *to = *from++;
  57   case 2: *to = *from++;
  58   case 1: *to = *from++;
  59   };
  60   }
  61 }
  62
  63 void copy4 (char *to, char* from, int count)
  64 {
  65   int n = (count+7)/8, i;
  66   switch (count%8) for (i=0; i<n; i++) {
  67   case 0: *to = *from++;
  68   case 7: *to = *from++;
  69   case 6: *to = *from++;
  70   case 5: *to = *from++;
  71   case 4: *to = *from++;
  72   case 3: *to = *from++;
  73   case 2: *to = *from++;
  74   case 1: *to = *from++;
  75   };
  76 }
  77
  78 void copy5 (char *to, char *from, int count)
  79 {
  80   int n = (count+7)/8, i;
  81   switch (count%8) {
  82   case 0: for (i=0; i<n; i++) {*to = *from++;
  83   case 7: *to = *from++;
  84   case 6: *to = *from++;
  85   case 5: *to = *from++;
  86   case 4: *to = *from++;
  87   case 3: *to = *from++;
  88   case 2: *to = *from++;
  89   case 1: *to = *from++;
  90   };
  91   }
  92 }
  93
  94 /* The semantics of func{0,1,2} () are the same:
  95  *   if (foo%2 == 0), func(foo) returns 2;
  96  *   if (foo%2 == 1), func(foo) returns 13 -- the initialization of the loop
  97  * is skipped, thus the loop behaves as if started from -11. */
  98
  99 int func0 (int foo)
 100 {
 101     int bar = 0, i = -11;
 102     switch (foo%2)
 103     {
 104     case 0:
 105       i=0;
 106       for(;i<2;) {
 107     case 1:
 108       bar += 1;
 109       i++;
 110     }
 111     }
 112     return bar;
 113 }
 114
 115 int func1 (int foo)
 116 {
 117     int bar = 0, i = -11;
 118     switch (foo%2)
 119     {
 120     case 0:
 121       i=0;
 122       while(i<2) {
 123     case 1:
 124       bar += 1;
 125       i++;
 126     }
 127     }
 128     return bar;
 129 }
 130
 131 int func2 (int foo)
 132 {
 133     int bar = 0, i = -11;
 134     switch (foo%2)
 135     {
 136     case 0:
 137       i=0;
 138       do {
 139     case 1:
 140       bar += 1;
 141       i++;
 142     } while (i<2);
 143     }
 144     return bar;
 145 }
 146
 147 int
 148 main(void)
 149 {
 150   if (func0 (7) != func1 (11))
 151     return 1;
 152   if (func0 (4) != func2 (8))
 153     return 1;
 154   if (func1 (6) != func2 (2))
 155     return 1;
 156
 157   return 0;
 158 }
 159
 160 /* The following two routines aren't true Duff's device implementations, but,
 161  * inspired by it, test the imbrication of switch with if/else block. */
 162 int func3 (int x)
 163 {
 164   int i = 0;
 165   switch(x%2) {
 166     case 0:
 167       i=x;
 168       if (i<10) {
 169     /*@fallthrough@*/
 170     default:
 171         i++;
 172       }
 173   }
 174
 175   return i;
 176 }
 177
 178 int func4 (int x)
 179 {
 180   int i = 0;
 181   switch(x%2) {
 182     case 0:
 183       if (i<10) {
 184         i=x;
 185       }
 186       else {
 187     /*@fallthrough@*/
 188     default:
 189         i++;
 190       }
 191   }
 192
 193   return i;
 194 }
 195