patches/cascade-test.c

   1 #include <comedi.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include "../comedi/drivers/8253.h"
   5
   6 #if NOT
   7 /* this function is meant to replace i8253_cascade_ns_to_timer_2div
   8  * (which is completely broken at the moment)
   9  */
  10 static inline void cascade_new(int i8253_osc_base, unsigned int *d1, unsigned int *d2, unsigned int *nanosec, int round_mode)
  11 {
  12         unsigned int divider;
  13         unsigned int div1, div2;
  14         unsigned int div1_glb, div2_glb, ns_glb;
  15         unsigned int div1_lub, div2_lub, ns_lub;
  16         unsigned int ns;
  17         unsigned int start;
  18         unsigned int ns_low, ns_high;
  19
  20         divider = *nanosec / i8253_osc_base;
  21
  22         div1_lub = div2_lub = 0;
  23         div1_glb = div2_glb = 0;
  24
  25         ns_glb = 0;
  26         ns_lub = 0xffffffff;
  27
  28         div2 = 0x10000;
  29         start = divider / div2;
  30         if(start < 2) start = 2;
  31         for (div1 = start; div1 <= divider / div1 + 1; div1++) {
  32                 for(div2 = divider / div1; div1 * div2 <= divider + div1 + 1; div2++) {
  33                         ns = i8253_osc_base * div1 * div2;
  34                         if (ns <= *nanosec && ns > ns_glb) {
  35                                 ns_glb = ns;
  36                                 div1_glb = div1;
  37                                 div2_glb = div2;
  38                         }
  39                         if (div2 <= 0x10000) {
  40                                 ns = i8253_osc_base * div1 * div2;
  41                                 if (ns >= *nanosec && ns < ns_lub) {
  42                                         ns_lub = ns;
  43                                         div1_lub = div1;
  44                                         div2_lub = div2;
  45                                 }
  46                         }
  47                 }
  48         }
  49
  50         switch (round_mode) {
  51         case TRIG_ROUND_NEAREST:
  52         default:
  53                 ns_high = div1_lub * div2_lub * i8253_osc_base;
  54                 ns_low = div1_glb * div2_glb * i8253_osc_base;
  55                 if( ns_high - *nanosec < *nanosec - ns_low) {
  56                         div1 = div1_lub;
  57                         div2 = div2_lub;
  58                 } else {
  59                         div1 = div1_glb;
  60                         div2 = div2_glb;
  61                 }
  62                 break;
  63         case TRIG_ROUND_UP:
  64                 div1 = div1_lub;
  65                 div2 = div2_lub;
  66                 break;
  67         case TRIG_ROUND_DOWN:
  68                 div1 = div1_glb;
  69                 div2 = div2_glb;
  70                 break;
  71         }
  72
  73         *nanosec = div1 * div2 * i8253_osc_base;
  74         *d1 = div1;
  75         *d2 = div2;
  76         return;
  77 }
  78 #endif
  79
  80 #ifdef ROGI
  81 int main(int argc,vhar *argv[])
  82 {
  83         int osc_base = 1000;
  84         int round_mode = TRIG_ROUND_NEAREST;
  85         int i;
  86         int div1_old, div2_old, ns_old, err_old;
  87         int div1_new, div2_new, ns_new, err_new;
  88         int div1_pow, div2_pow, ns_pow, err_pow;
  89         int err = 0;
  90
  91         /* loop over desired nanosecond timings to test */
  92         for(i = 10000; i < 100000; i++)
  93         {
  94                 ns_old = ns_new = ns_pow = i;
  95
  96                 i8253_cascade_ns_to_timer_2div(osc_base, &div1_old, &div2_old, &ns_old, round_mode);
  97                 err_old = ns_old - i;
  98
  99                 i8253_cascade_ns_to_timer_power(osc_base, &div1_pow, &div2_pow, &ns_pow, round_mode);
 100                 err_pow = ns_pow - i;
 101
 102                 cascade_new(osc_base, &div1_new, &div2_new, &ns_new, round_mode);
 103                 err_new = ns_new - i;
 104
 105                 /* print results on this condition */
 106                 if(abs(err_new) > abs(err_pow))
 107                         printf("nanosec %i\terr_new %i\tdiv1_new %i\tdiv2_new %i\n"
 108                                 "\t\terr_pow %i\tdiv1_pow %i\tdiv2_pow %i\n",
 109                                 i, err_new, div1_new, div2_new, err_pow, div1_pow, div2_pow);
 110
 111         /* consistency checks */
 112                 if(div1_old * div2_old * osc_base != ns_old) err = 1;
 113                 if(div1_pow * div2_pow * osc_base != ns_pow) err = 2;
 114                 if(div1_new * div2_new * osc_base != ns_new) err = 3;
 115                 if(err)
 116                 {
 117                         printf("err %i\n", err);
 118                         err=0;
 119                 }
 120         }
 121         return 0;
 122 }
 123 #endif
 124
 125 int main(int argc,char *argv[])
 126 {
 127         int osc_base = 1000;
 128         unsigned int ns;
 129         unsigned int div1,div2;
 130         int i=0;
 131
 132         for(ns = 4*osc_base; ns<0x80000000;ns++){
 133                 i8253_cascade_ns_to_timer_2div
 134                         (osc_base, &div1, &div2, &ns, TRIG_ROUND_UP);
 135
 136                 i++;
 137                 if(!(i&0xff))
 138                         printf("ns=%d div1=%d div2=%d\n",ns,div1,div2);
 139                 if(i==100000)exit(0);
 140         }
 141
 142         return 0;
 143 }
 144