mpegimda.s

Application (fix point) for playing MP3 data on embedded systems. mp3play is designed to be able to

;------------------------------------------------------------------------------
;
;   File    :   MPEGIMDA.a
;
;   Author  :   St閜hane TAVENARD
;
;   $VER:   MPEGIMDA.a  0.1  (10/05/1997)
;
;   (C) Copyright 1997-1997 St閜hane TAVENARD
;       All Rights Reserved
;
;   #Rev|   Date   |                      Comment
;   ----|----------|--------------------------------------------------------
;   0   |04/03/1997| Initial revision                                     ST
;   1   |10/05/1997| use of link instead of static vars                   ST
;
;   ------------------------------------------------------------------------
;
;   MPEG IMDCT optimized !
;
;------------------------------------------------------------------------------

               XDEF     @MPEGIMDA_hybrid
               XDEF     _MPEGIMDA_hybrid

               section  ASMCODE,code

IMDCT_BITS     equ      14

;              Perform an IMDCT
;
;              a0:  in array (16-bit)
;              a1:  out array (16-bit)
;              a2:  prev block (16-bit)
;              d0.w: block type
;              d1.w: mixed (0 or 1)
;              d2.w: sb_max
;
@MPEGIMDA_hybrid
_MPEGIMDA_hybrid
               movem.l  d2-d7/a2-a6,-(sp)

               move.l   a2,a3    ; a3 = prev block

               clr.w    d5

               tst.w    d1
               beq      MPEGIMDA_h1
               ; mixed -> sb 0 & 1 to win 0
               lea      imdct_win0,a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_l
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
               lea      imdct_win0_odd,a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_l
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
MPEGIMDA_h1
               cmp.w    #2,d0
               beq      MPEGIMDA_h3 ; short blocks

               ; Long blocks
MPEGIMDA_h2
               lea      imdct_win,a2
               move.l   (a2,d0.w*4),a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_l
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
               lea      imdct_win_odd,a2
               move.l   (a2,d0.w*4),a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_l
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
               bra      MPEGIMDA_h2

               ; Short blocks
MPEGIMDA_h3
               lea      imdct_win2,a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_s
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
               lea      imdct_win2_odd,a2
               movem.w  d0/d2,-(sp)
               bsr      imdct_s
               movem.w  (sp)+,d0/d2
               add.l    #2*18,a0    ; in += 18
               addq.l   #2,a1       ; out++;
               add.l    #2*18,a3    ; prev += 18
               addq.w   #1,d5
               cmp.w    d2,d5
               bge      MPEGIMDA_h5 ; end of imdct
               bra      MPEGIMDA_h3

               ; End of imdct -> overlap with 0 rest of bands
MPEGIMDA_h5
               cmp.w    #32,d5
               bge      MPEGIMDA_h7
               clr.l    d1
MPEGIMDA_h6
               move.w   (a3),0*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),1*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),2*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),3*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),4*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),5*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),6*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),7*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),8*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),9*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),10*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),11*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),12*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),13*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),14*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),15*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),16*2*32(a1)
               move.w   d1,(a3)+
               move.w   (a3),17*2*32(a1)
               move.w   d1,(a3)+
               addq.l   #2,a1    ; out++
               addq.w   #1,d5
               cmp.w    #32,d5
               blt      MPEGIMDA_h6

MPEGIMDA_h7
               movem.l  (sp)+,d2-d7/a2-a6
               rts

#define	K0      16368
#define	K1      16244
#define	K2      15996
#define	K3      15626
#define	K4      15137
#define	K5      14533
#define	K6      13818
#define	K7      12998
#define	K8      12080
#define	K9      11069
#define	K10      9974
#define	K11      8803
#define	K12      7565
#define	K13      6270
#define	K14      4927
#define	K15      3546
#define	K16      2139
#define	K17      715

#define	MUL32	muls.l $$1,$$2 \
		asr.l	%d6,$$2
		
#if 0	
MUL32          MACRO
               muls.l   \1,\2       ; ##7
               asr.l    d6,\2       ; ##7
               ENDM
#endif
/*	
;              S   a, <dummy reg>, <dest reg>
;              performs: (INT32)x[ a ] - (INT32)x[ 11-a ] - (INT32)x[ 12+a ]
;
*/	
#if 0	
S              MACRO
               move.w   \1*2(a0),\3
               ext.l    \3
               move.w   22-\1*2(a0),\2
               ext.l    \2
               sub.l    \2,\3
               move.w   24+\1*2(a0),\2
               ext.l    \2
               sub.l    \2,\3
               ENDM
#else
#define S      move.w   $$1*2(%a0),$$3 \
               ext.l    $$3 \
               move.w   22-$$1*2(%a0),$$2 \
               ext.l    $$2 \
               sub.l    $$2,$$3 \
               move.w   24+$$1*2(%a0),%%2 \
               ext.l    $$2
               sub.l    $$2,$$3
#endif
#if 0
;              M   xi, Kx, <dest reg>
;              performs: ((INT32)x[ xi ] * (Kx))
;
M              MACRO
               move.w   \1*2(a0),\3
               muls.w   #\2,\3
               ENDM
#else
#define	M      move.w   $$1*2(a0),$$3 \
               muls.w   #$$2,$$3
#endif
#if 0
;
;              M_ADD xi, Kx
;              performs: M xi, Kx, d0
;                        add.l  d0,d3
;
M_ADD          MACRO
               M        \1,\2,d0
               add.l    d0,d3
               ENDM
#else
#define	M_ADD  M        $$1,$$2,%d0 \
               add.l    %d0,%d3
#endif
#if 0
;
;                          M_SUB xi, Kx
;              performs: M xi, Kx, d0
;                        sub.l  d0,d3
;

M_SUB          MACRO
               M        \1,\2,d0
               sub.l    d0,d3
               ENDM
#else
#define	M_SUB  M        $$1,$$2,%d0 \
               sub.l    %d0,%d3 

#if 0
;              MT   ti, Kx, <dest reg>
;              performs: (t[ ti ] * (Kx))
;
MT             MACRO
               move.l   \1*4(a3),\3
               muls.w   #\2,\3
               ENDM

#else
#define	MT     move.l   %%1*4(%a3),$$3 \
               muls.w   #$$2,$$3
#endif
#if 0
;
;                          MT_ADD ti, Kx
;              performs: M ti, Kx, d0
;                        add.l  d0,d3
;
MT_ADD         MACRO
               MT       \1,\2,d0
               add.l    d0,d3
               ENDM
#else
#define	MT_ADD MT       $$1,$$2,%d0 \
               add.l    %d0,%d3
#endif
#if 0
;
;                          MT_SUB ti, Kx
;              performs: MT ti, Kx, d0
;                        sub.l  d0,d3
;
MT_SUB          MACRO
               MT       \1,\2,d0
               sub.l    d0,d3
               ENDM

#else
#define	MT_SUB MT       $$1,$$2,%d0 \
               sub.l    %d0,%d3

#endif
#if 0
;
;              IMDCT_FIX <reg>
;              performs <reg> = <reg> >> IMDCT_BITS
;
IMDCT_FIX      MACRO
               asr.l    d6,\1
               ENDM
#else
#define	IMDCT_FIX	asr.l    d6,$$1
#endif
#if 0
;              W   <reg>, wi   -> <reg> -> out[ wi ]
;              performs: (<reg> * win[ wi ]) >> WIN_BITS + prev[ wi ] -> out[ wi ]
;
W              MACRO
               muls.w   \2*2(a2),\1
               asr.l    d6,\1
               add.w    \2*2(a5),\1
               move.w   \1,\2*2*32(a1)
               ENDM
#else
#define	W      muls.w   $$2*2(%a2),%%1 \
               asr.l    %d6,$$1 \
               add.w    $$2*2(%a5),$$1 \
               move.w   $$1,$$2*2*32(%a1)
#endif
#if 0

;              WP   <reg>, wi   -> <reg> -> prev[ wi ]
;              performs: (<reg> * win[ wi ]) >> WIN_BITS -> prev[ wi-18 ]
;
WP             MACRO
               muls.w   \2*2(a2),\1
               asr.l    d6,\1
               move.w   \1,\2*2-36(a5)
               ENDM
#else
#define	WP     muls.w   $$2*2(%a2),$$1 \
               asr.l    %d6,$$1 \
               move.w   $$1,%%2*2-36(%a5) 
#endif
;
;              IMDCT for Long blocks
;
;              a0: input  x array (16-bit)
;              a1: output out     (16-bit)
;              a2: window array   (16-bit)
;              a3: prev array     (32-bit)
imdct_l:
               link     %a6,#-10*4    ; need 4+6 longs
               move.l   %a3,%a5
               lea      -4*4(%a6),%a3   ; t needs 4 longs
               lea      -6*4(%a3),%a4   ; s needs 6 longs
;               lea      imdct_sum_t,%a3
;               lea      imdct_sum_s,%a4
               moveq.l  #IMDCT_BITS,%d6

               M        4,K13,%d1
               M        13,K4,%d0
               sub.l    %d0,%d1      ; k1 = M( 4, K13 ) - M( 13, K4 )
               M        4,K4,%d2
               M        13,K13,%d0
               add.l    %d0,%d2      ; k2 = M( 4, K4 )  + M( 13, K13 )

; s[ 0 ] = -M( 1, K7 )  + k1 + M( 7, K1 )  + M( 10, K16 ) - M( 16, K10 )
               M        7,K1,%d3
               M_SUB    1,K7
               M_ADD    10,K16
               M_SUB    16,K10
               add.l    %d1,%d3
               move.l   %d3,0*4(%a4)

; s[ 1 ] = -M( 1, K4 )  - k1 + M( 7, K13 ) + M( 10, K4 )  + M( 16, K13 )
               M        7,K13,%d3
               M_SUB    1,K4
               M_ADD    10,K4
               M_ADD    16,K13
               sub.l    %d1,%d3
               move.l   %d3,1*4(a4)

; s[ 2 ] = -M( 1, K1 )  - k2 - M( 7, K7 )  - M( 10, K10 ) - M( 16, K16 )
               M        7,K7,%d3
               neg.l    %d3
               M_SUB    1,K1
               M_SUB    10,K10
               M_SUB    16,K16