runtime/basis/Real/gdtoa.c

   1 #include "platform.h"
   2 #include "gdtoa/gdtoa.h"
   3
   4 /* This code is patterned on g_ffmt from the gdtoa sources. */
   5 C_String_t Real32_gdtoa (Real32_t f, C_Int_t mode, C_Int_t ndig,
   6                          C_Int_t rounding, Ref(C_Int_t) decpt) {
   7   FPI fpi = { 24, 1-127-24+1, 254-127-24+1, (int)rounding, 0, 6 };
   8   ULong bits[1], L[1];
   9   int ex, i;
  10   char *result;
  11
  12   memcpy(L, &f, sizeof(Real32_t));
  13   bits[0] = L[0] & 0x7fffff;
  14   if ((ex = (L[0] >> 23) & 0xff) != 0)
  15     bits[0] |= 0x800000;
  16   else
  17     ex = 1;
  18   ex -= 0x7f + 23;
  19   i = STRTOG_Normal;
  20   result = gdtoa__gdtoa (&fpi, ex, bits, &i, (int)mode, (int)ndig, (int*)decpt, NULL);
  21   return (C_String_t)result;
  22 }
  23
  24 /* This code is patterned on g_dfmt from the gdtoa sources. */
  25 C_String_t Real64_gdtoa (Real64_t d, C_Int_t mode, C_Int_t ndig,
  26                          C_Int_t rounding, Ref(C_Int_t) decpt) {
  27   FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, (int)rounding, 0, 14 };
  28   ULong bits[2], L[2];
  29   int ex, i;
  30   char *result;
  31   int x0, x1;
  32
  33   if (isBigEndian()) {
  34     x0 = 0;
  35     x1 = 1;
  36   } else {
  37     x0 = 1;
  38     x1 = 0;
  39   }
  40   memcpy(L, &d, sizeof(Real64_t));
  41   bits[0] = L[x1];
  42   bits[1] = L[x0] & 0xfffff;
  43   if ((ex = (L[x0] >> 20) & 0x7ff) != 0)
  44     bits[1] |= 0x100000;
  45   else
  46     ex = 1;
  47   ex -= 0x3ff + 52;
  48   i = STRTOG_Normal;
  49   result = gdtoa__gdtoa (&fpi, ex, bits, &i, mode, ndig, (int*)decpt, NULL);
  50   return (C_String_t)result;
  51 }