softfloat/f64_to_i64_r_minMag.c

   1
   2 #include <stdbool.h>
   3 #include <stdint.h>
   4 #include "platform.h"
   5 #include "internals.h"
   6 #include "softfloat.h"
   7
   8 int_fast64_t f64_to_i64_r_minMag( float64_t a, bool exact )
   9 {
  10     union ui64_f64 uA;
  11     uint_fast64_t uiA;
  12     bool sign;
  13     int_fast16_t exp;
  14     uint_fast64_t sig;
  15     int_fast16_t shiftCount;
  16     int_fast64_t absZ;
  17
  18     uA.f = a;
  19     uiA = uA.ui;
  20     sign = signF64UI( uiA );
  21     exp = expF64UI( uiA );
  22     sig = fracF64UI( uiA );
  23     shiftCount = exp - 0x433;
  24     if ( 0 <= shiftCount ) {
  25         if ( 0x43E <= exp ) {
  26             if ( uiA != packToF64UI( 1, 0x43E, 0 ) ) {
  27                 softfloat_raiseFlags( softfloat_flag_invalid );
  28                 if ( ! sign || ( ( exp == 0x7FF ) && sig ) ) {
  29                     return INT64_C( 0x7FFFFFFFFFFFFFFF );
  30                 }
  31             }
  32             return - INT64_C( 0x7FFFFFFFFFFFFFFF ) - 1;
  33         }
  34         sig |= UINT64_C( 0x0010000000000000 );
  35         absZ = sig<<shiftCount;
  36     } else {
  37         if ( exp < 0x3FF ) {
  38             if ( exact && ( exp | sig ) ) {
  39                 softfloat_exceptionFlags |= softfloat_flag_inexact;
  40             }
  41             return 0;
  42         }
  43         sig |= UINT64_C( 0x0010000000000000 );
  44         absZ = sig>>( - shiftCount );
  45         if ( exact && (uint64_t) ( sig<<( shiftCount & 63 ) ) ) {
  46             softfloat_exceptionFlags |= softfloat_flag_inexact;
  47         }
  48     }
  49     return sign ? - absZ : absZ;
  50
  51 }
  52