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- #include "log2.h"
- const char log2_id[] = "@(#)$Id $" log2_h;
-
- #include "typedef.h"
- #include "basic_op.h"
- #include "count.h"
-
- #include "log2.tab"
-
- void Log2_norm (
- Word32 L_x,
- Word16 exp,
- Word16 *exponent,
- Word16 *fraction
- )
- {
- Word16 i, a, tmp;
- Word32 L_y;
- test ();
- if (L_x <= (Word32) 0)
- {
- *exponent = 0; move16 ();
- *fraction = 0; move16 ();
- return;
- }
- *exponent = sub_ex (30, exp); move16 ();
- L_x = L_shr_ex (L_x, 9);
- i = extract_h_ex (L_x);
- L_x = L_shr_ex (L_x, 1);
- a = extract_l_ex (L_x);
- a = a & (Word16) 0x7fff; logic16 ();
- i = sub_ex (i, 32);
- L_y = L_deposit_h_ex (table[i]);
- tmp = sub_ex (table[i], table[i + 1]);
- L_y = L_msu_ex (L_y, tmp, a);
- *fraction = extract_h_ex (L_y);move16 ();
- return;
- }
- void Log2 (
- Word32 L_x,
- Word16 *exponent,
- Word16 *fraction
- )
- {
- Word16 exp;
- exp = norm_l_ex (L_x);
- Log2_norm (L_shl_ex (L_x, exp), exp, exponent, fraction);
- }
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