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view libgsmefr/basic_op.h @ 242:f081a6850fb5

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libgsmfrp: new refined implementation The previous implementation exhibited the following defects, which are now fixed: 1) The last received valid SID was cached forever for the purpose of handling future invalid SIDs - we could have received some valid SID ages ago, then lots of speech or NO_DATA, and if we then get an invalid SID, we would resurrect the last valid SID from ancient history - a bad design. In our new design, we handle invalid SID based on the current state, much like BFI. 2) GSM 06.11 spec says clearly that after the second lost SID (received BFI=1 && TAF=1 in CN state) we need to gradually decrease the output level, rather than jump directly to emitting silence frames - we previously failed to implement such logic. 3) Per GSM 06.12 section 5.2, Xmaxc should be the same in all 4 subframes in a SID frame. What should we do if we receive an otherwise valid SID frame with different Xmaxc? Our previous approach would replicate this Xmaxc oddity in every subsequent generated CN frame, which is rather bad. In our new design, the very first CN frame (which can be seen as a transformation of the SID frame itself) retains the original 4 distinct Xmaxc, but all subsequent CN frames are based on the Xmaxc from the last subframe of the most recent SID.
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 09 May 2023 05:16:31 +0000
parents 38326102fc43
children 1c514150c033
line wrap: on
line source

/*___________________________________________________________________________
 |                                                                           |
 |   Constants and Globals                                                   |
 |___________________________________________________________________________|
*/
extern __thread Flag Overflow;
extern __thread Flag Carry;

#define MAX_32 (Word32)0x7fffffffL
#define MIN_32 (Word32)0x80000000L

#define MAX_16 (Word16)0x7fff
#define MIN_16 (Word16)0x8000

/*___________________________________________________________________________
 |                                                                           |
 |   Prototypes for basic arithmetic operators                               |
 |___________________________________________________________________________|
*/

Word16 add (Word16 var1, Word16 var2);    /* Short add,           1   */
Word16 sub (Word16 var1, Word16 var2);    /* Short sub,           1   */
Word16 abs_s (Word16 var1);               /* Short abs,           1   */
Word16 shl (Word16 var1, Word16 var2);    /* Short shift left,    1   */
Word16 shr (Word16 var1, Word16 var2);    /* Short shift right,   1   */
Word16 mult (Word16 var1, Word16 var2);   /* Short mult,          1   */
Word32 L_mult (Word16 var1, Word16 var2); /* Long mult,           1   */
Word16 negate (Word16 var1);              /* Short negate,        1   */
Word16 extract_h (Word32 L_var1);         /* Extract high,        1   */
Word16 extract_l (Word32 L_var1);         /* Extract low,         1   */
Word16 round (Word32 L_var1);             /* Round,               1   */
Word32 L_mac (Word32 L_var3, Word16 var1, Word16 var2);   /* Mac,  1  */
Word32 L_msu (Word32 L_var3, Word16 var1, Word16 var2);   /* Msu,  1  */
Word32 L_macNs (Word32 L_var3, Word16 var1, Word16 var2); /* Mac without
                                                             sat, 1   */
Word32 L_msuNs (Word32 L_var3, Word16 var1, Word16 var2); /* Msu without
                                                             sat, 1   */
Word32 L_add (Word32 L_var1, Word32 L_var2);    /* Long add,        2 */
Word32 L_sub (Word32 L_var1, Word32 L_var2);    /* Long sub,        2 */
Word32 L_add_c (Word32 L_var1, Word32 L_var2);  /* Long add with c, 2 */
Word32 L_sub_c (Word32 L_var1, Word32 L_var2);  /* Long sub with c, 2 */
Word32 L_negate (Word32 L_var1);                /* Long negate,     2 */
Word16 mult_r (Word16 var1, Word16 var2);       /* Mult with round, 2 */
Word32 L_shl (Word32 L_var1, Word16 var2);      /* Long shift left, 2 */
Word32 L_shr (Word32 L_var1, Word16 var2);      /* Long shift right, 2*/
Word16 shr_r (Word16 var1, Word16 var2);        /* Shift right with
                                                   round, 2           */
Word16 mac_r (Word32 L_var3, Word16 var1, Word16 var2); /* Mac with
                                                           rounding,2 */
Word16 msu_r (Word32 L_var3, Word16 var1, Word16 var2); /* Msu with
                                                           rounding,2 */
Word32 L_deposit_h (Word16 var1);        /* 16 bit var1 -> MSB,     2 */
Word32 L_deposit_l (Word16 var1);        /* 16 bit var1 -> LSB,     2 */

Word32 L_shr_r (Word32 L_var1, Word16 var2); /* Long shift right with
                                                round,  3             */
Word32 L_abs (Word32 L_var1);            /* Long abs,              3  */
Word32 L_sat (Word32 L_var1);            /* Long saturation,       4  */
Word16 norm_s (Word16 var1);             /* Short norm,           15  */
Word16 div_s (Word16 var1, Word16 var2); /* Short division,       18  */
Word16 norm_l (Word32 L_var1);           /* Long norm,            30  */