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  1. /* tifloat.c */
  2. /*****************************************************************************/
  3. /* SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only                     */
  4. /*                                                                           */
  5. /* AS                                                                        */
  6. /*                                                                           */
  7. /* IEEE -> TI DSP Floating Point Conversion on host                          */
  8. /*                                                                           */
  9. /*****************************************************************************/
  10.  
  11. #include <errno.h>
  12.  
  13. #include "as_float.h"
  14. #include "errmsg.h"
  15. #include "tifloat.h"
  16.  
  17. /*!------------------------------------------------------------------------
  18.  * \fn     split_exp(as_float_t inp, LongInt *p_exponent, LongWord *p_mantissa)
  19.  * \brief  common number dissection
  20.  * \param  inp float input (host format)
  21.  * \param  p_exponent exponent (without bias)
  22.  * \param  p_mantissa mantissa (two's complement)
  23.  * \return 0 or error code
  24.  * ------------------------------------------------------------------------ */
  25.  
  26. static int split_exp(as_float_t inp, LongInt *p_exponent, LongWord *p_mantissa)
  27. {
  28.   as_float_dissect_t dissect;
  29.  
  30.   as_float_dissect(&dissect, inp);
  31.   if ((dissect.fp_class != AS_FP_NORMAL)
  32.    && (dissect.fp_class != AS_FP_SUBNORMAL))
  33.     return -EINVAL;
  34.  
  35.   *p_exponent = dissect.exponent;
  36.   if (dissect.mantissa_bits < 32)
  37.     as_float_append_mantissa_bits(&dissect, 0, 32 - dissect.mantissa_bits);
  38.   *p_mantissa = as_float_mantissa_extract(&dissect, 0, 32);
  39.   if (dissect.negative)
  40.     *p_mantissa = (0xffffffff - *p_mantissa) + 1;
  41.   *p_mantissa = (*p_mantissa) ^ 0x80000000;
  42.  
  43.   return 0;
  44. }
  45.  
  46. /*!------------------------------------------------------------------------
  47.  * \fn     as_float_2_ti2(as_float_t inp, Word *p_dest)
  48.  * \brief  convert host float to C3x/4x short (16 bits)
  49.  * \param  inp float input (host format)
  50.  * \param  result buffer
  51.  * \return 0 or error code
  52.  * ------------------------------------------------------------------------ */
  53.  
  54. int as_float_2_ti2(as_float_t inp, Word *p_dest)
  55. {
  56.   int ret;
  57.   LongInt exponent;
  58.   LongWord mantissa;
  59.  
  60.   if (inp == 0)
  61.   {
  62.     *p_dest = 0x8000;
  63.     return 0;
  64.   }
  65.  
  66.   if ((ret = split_exp(inp, &exponent, &mantissa)) < 0)
  67.     return ret;
  68.   if (!ChkRange(exponent, -7, 7))
  69.     return -E2BIG;
  70.   *p_dest = ((exponent << 12) & 0xf000) | ((mantissa >> 20) & 0xfff);
  71.   return 0;
  72. }
  73.  
  74. /*!------------------------------------------------------------------------
  75.  * \fn     as_float_2_ti4(as_float_t inp, LongWord *p_dest)
  76.  * \brief  convert host float to C3x/4x single (32 bits)
  77.  * \param  inp float input (host format)
  78.  * \param  result buffer
  79.  * \return 0 or error code
  80.  * ------------------------------------------------------------------------ */
  81.  
  82. int as_float_2_ti4(as_float_t inp, LongWord *p_dest)
  83. {
  84.   int ret;
  85.   LongInt exponent;
  86.   LongWord mantissa;
  87.  
  88.   if (inp == 0)
  89.   {
  90.     *p_dest = 0x80000000;
  91.     return 0;
  92.   }
  93.  
  94.   if ((ret = split_exp(inp, &exponent, &mantissa)) < 0)
  95.     return ret;
  96.   if (!ChkRange(exponent, -127, 127))
  97.     return -E2BIG;
  98.   *p_dest = ((exponent << 24) & 0xff000000) + (mantissa >> 8);
  99.   return 0;
  100. }
  101.  
  102. /*!------------------------------------------------------------------------
  103.  * \fn     as_float_2_ti5(as_float_t inp, LongWord *p_dest_l, LongWord *p_dest_h)
  104.  * \brief  convert host float to C3x/4x extended (40 bits)
  105.  * \param  inp float input (host format)
  106.  * \param  p_dest_l result buffer (mantissa)
  107.  * \param  p_dest_h result buffer (exponent)
  108.  * \return 0 or error code
  109.  * ------------------------------------------------------------------------ */
  110.  
  111. int as_float_2_ti5(as_float_t inp, LongWord *p_dest_l, LongWord *p_dest_h)
  112. {
  113.   int ret;
  114.   LongInt exponent;
  115.  
  116.   if (inp == 0)
  117.   {
  118.     *p_dest_h = 0x80;
  119.     *p_dest_l = 0x00000000;
  120.     return 0;
  121.   }
  122.  
  123.   if ((ret = split_exp(inp, &exponent, p_dest_l)) < 0)
  124.     return ret;
  125.   if (!ChkRange(exponent, -127, 127))
  126.     return -E2BIG;
  127.   *p_dest_h = exponent & 0xff;
  128.  return 0;
  129. }
  130.