dynamicArray

     1 
     2 #include "libdarray.h"
     3 
     4 bool dArrayIsValidIndex(intmax_t index) {
     5     if (index >= ((intmax_t)1)<<dArrayAddrSpace) {
     6         return false;
     7     }
     8     return true;
     9 }
    10 
    11 dArrayIxt dArrayIndex(intmax_t index) {
    12     dArrayIxt r;
    13     if (index >= ((intmax_t)1)<<dArrayAddrSpace) {
    14         r.error = true;
    15         return r;
    16     }
    17     r.error = false;
    18 
    19     intmax_t bufx = index >> dArrayBaseBits;
    20     if (!bufx) {
    21         r.ix     = 0;
    22         r.offset = index;
    23     }
    24     else {
    25         //int pos = 0;
    26         /* for (int i = (bufx >> 1); i != 0; pos++) { */
    27         /*     i >>= 1; */
    28         /* } */
    29         /* find position of MSB */
    30 #if __LP64__
    31         asm ("bsrq %1, %0" : "=r" (r.ix) : "r" (bufx));
    32 #else
    33         asm ("bsrl %1, %0" : "=r" (r.ix) : "r" (bufx));
    34 #endif
    35         intmax_t mask = ~(0xFFFFFFFFFFFFFFFF << (dArrayBaseBits+r.ix));
    36         r.ix++;
    37         r.offset = index & mask;
    38     }
    39     return r;
    40 }