text: #include "stdio.h"
  #ifndef mips
  #include "stdlib.h"
  #endif
  #include "xlisp.h"
  #include "sound.h"
  
  #include "falloc.h"
  #include "cext.h"
  #include "fmfb.h"
  
  void fmfb_free(snd_susp_type a_susp);
  
  
  typedef struct fmfb_susp_struct {
      snd_susp_node susp;
      int64_t terminate_cnt;
  
      double yy;
      double sin_y;
      double xx;
      double x_incr;
      double index;
  } fmfb_susp_node, *fmfb_susp_type;
  
  
  void fmfb__fetch(snd_susp_type a_susp, snd_list_type snd_list)
  {
      fmfb_susp_type susp = (fmfb_susp_type) a_susp;
      int cnt = 0; /* how many samples computed */
      int togo;
      int n;
      sample_block_type out;
      register sample_block_values_type out_ptr;
  
      register sample_block_values_type out_ptr_reg;
  
      register double yy_reg;
      register double sin_y_reg;
      register double xx_reg;
      register double x_incr_reg;
      register double index_reg;
      falloc_sample_block(out, "fmfb__fetch");
      out_ptr = out->samples;
      snd_list->block = out;
  
      while (cnt < max_sample_block_len) { /* outer loop */
          /* first compute how many samples to generate in inner loop: */
          /* don't overflow the output sample block: */
          togo = max_sample_block_len - cnt;
  
          /* don't run past terminate time */
          if (susp->terminate_cnt != UNKNOWN &&
              susp->terminate_cnt <= susp->susp.current + cnt + togo) {
              togo = (int) (susp->terminate_cnt - (susp->susp.current + cnt));
              if (togo < 0) togo = 0;  /* avoids rounding errros */
              if (togo == 0) break;
          }
  
          n = togo;
          yy_reg = susp->yy;
          sin_y_reg = susp->sin_y;
          xx_reg = susp->xx;
          x_incr_reg = susp->x_incr;
          index_reg = susp->index;
          out_ptr_reg = out_ptr;
          if (n) do { /* the inner sample computation loop */
              xx_reg += x_incr_reg;
              if (xx_reg > SINE_TABLE_LEN) xx_reg -= SINE_TABLE_LEN;
              /* xx_reg incremented and index_reg scaled to table index_reg, and
                 sin_y_reg is a signal (-1 to +1) */
              yy_reg = xx_reg + index_reg * sin_y_reg;
              /* so yy_reg is a table index_reg */
              while (yy_reg > SINE_TABLE_LEN) yy_reg -= SINE_TABLE_LEN;
              while (yy_reg < 0) yy_reg += SINE_TABLE_LEN;
              sin_y_reg = sine_table[(int) yy_reg]; /* truncation gets valid index_reg */
              /* sin_y_reg is now a signal not ready for table lookup */
              *out_ptr_reg++ = (sample_type) sin_y_reg;
          } while (--n); /* inner loop */
  
          susp->yy = yy_reg;
          susp->sin_y = sin_y_reg;
          susp->xx = xx_reg;
          susp->index = index_reg;
          out_ptr += togo;
          cnt += togo;
      } /* outer loop */
  
      /* test for termination */
      if (togo == 0 && cnt == 0) {
          snd_list_terminate(snd_list);
      } else {
          snd_list->block_len = cnt;
          susp->susp.current += cnt;
      }
  } /* fmfb__fetch */
  
  
  void fmfb_free(snd_susp_type a_susp)
  {
      fmfb_susp_type susp = (fmfb_susp_type) a_susp;
      ffree_generic(susp, sizeof(fmfb_susp_node), "fmfb_free");
  }
  
  
  void fmfb_print_tree(snd_susp_type a_susp, int n)
  {
  }
  
  
  sound_type snd_make_fmfb(time_type t0, double hz, rate_type sr, double index, time_type d)
  {
      register fmfb_susp_type susp;
      /* sr specified as input parameter */
      /* t0 specified as input parameter */
      sample_type scale_factor = 1.0F;
      falloc_generic(susp, fmfb_susp_node, "snd_make_fmfb");
      susp->yy = 0.0;
      susp->sin_y = 0.0;
      susp->xx = 0.0;
      susp->x_incr = hz * SINE_TABLE_LEN / sr;
      susp->index = index * SINE_TABLE_LEN / PI2;
      susp->susp.fetch = fmfb__fetch;
  
      susp->terminate_cnt = check_terminate_cnt(ROUNDBIG((d) * sr));
      /* initialize susp state */
      susp->susp.free = fmfb_free;
      susp->susp.sr = sr;
      susp->susp.t0 = t0;
      susp->susp.mark = NULL;
      susp->susp.print_tree = fmfb_print_tree;
      susp->susp.name = "fmfb";
      susp->susp.log_stop_cnt = UNKNOWN;
      susp->susp.current = 0;
      return sound_create((snd_susp_type)susp, t0, sr, scale_factor);
  }
  
  
  sound_type snd_fmfb(time_type t0, double hz, rate_type sr, double index, time_type d)
  {
      return snd_make_fmfb(t0, hz, sr, index, d);
  }
  