mpegimda.a

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

;              W33   <reg>, oi, wi   -> <reg> * win[ wi ] + out[ oi*32 ] -> out[ oi*32 ]
;              performs: (<reg> * win[ wi ]) >> WIN_BITS + out[ oi*32 ] -> out[ oi*32 ]
;
W33            MACRO
               muls.w   \3*2(a2),\1
               asr.l    d6,\1
               add.w    \1,\2*2*32(a1)
               ENDM

;              W34   <reg>, oi, wi   -> <reg> * win[ wi ] -> prev[ oi ]
;              performs: (<reg> * win[ wi ]) >> WIN_BITS -> prev[ oi ]
;
W34            MACRO
               muls.w   \3*2(a2),\1
               asr.l    d6,\1
               move.w   \1,\2*2(a5)
               ENDM

;              W35   <reg>, oi, wi   -> <reg> * win[ wi ] + prev[ oi ] -> prev[ oi ]
;              performs: (<reg> * win[ wi ]) >> WIN_BITS + prev[ oi ] -> prev[ oi ]
;
W35            MACRO
               muls.w   \3*2(a2),\1
               asr.l    d6,\1
               add.w    \1,\2*2(a5)
               ENDM

;
;              IMDCT for Short blocks
;
;              a0: input  x array (16-bit)
;              a1: output out     (16-bit)
;              a2: window array   (16-bit)
;              a3: prev array     (32-bit)
imdct_s
;   move.w #$F00,$DFF180
               link     a6,#-4*4    ; need 2+2 longs
               move.l   a3,a5
               lea      -2*4(a6),a3   ; t needs 2 longs
               lea      -2*4(a3),a4   ; s needs 2 longs
;               lea      imdct_sum_t,a3
;               lea      imdct_sum_s,a4
               moveq.l  #IMDCT_BITS,d6

               ; STEP 1
               ; O( 0..5 ) = prev[ 0.. 5 ]

               move.w   0*2(a5),0*2*32(a1)
               move.w   1*2(a5),1*2*32(a1)
               move.w   2*2(a5),2*2*32(a1)
               move.w   3*2(a5),3*2*32(a1)
               move.w   4*2(a5),4*2*32(a1)
               move.w   5*2(a5),5*2*32(a1)

               ; Calc s[0..1],  t[0..1]
               ;
               M3       1,K1,d3
               M3_ADD   4,K4
               move.l   d3,0*4(a4) ; s[ 0 ] = M3( 1, K1 ) + M3( 4, K4 )
               M3       1,K4,d3
               M3_SUB   4,K1
               move.l   d3,1*4(a4) ; s[ 1 ] = M3( 1, K4 ) - M3( 4, K1 )

               move.w   0*6(a0),d3
               sub.w    3*6(a0),d3
               ext.l    d3
               move.l   d3,0*4(a3) ; t[ 0 ] =  x[0*3] - x[3*3]
               move.w   2*6(a0),d3
               add.w    5*6(a0),d3
               ext.l    d3
               move.l   d3,1*4(a3) ; t[ 1 ] =  x[2*3] + x[5*3]

               ; 0
               M3       0,K3,d3
               M3_SUB   2,K5
               M3_ADD   3,K0
               M3_SUB   5,K2
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W31      d3,6,0
               W31      d4,11,5
               ; 1
               MT       0,K4,d3
               MT_ADD   1,K1
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W31      d3,7,1
               W31      d4,10,4
               ; 2
               M3       0,K5,d3
               M3_ADD   2,K3
               M3_SUB   3,K2
               M3_SUB   5,K0
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W31      d3,8,2
               W31      d4,9,3

               ; 3+3
               M3       0,K2,d3
               neg.l    d3
               M3_ADD   2,K0
               M3_ADD   3,K5
               M3_SUB   5,K3
               add.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W32      d3,12,6
               W32      d4,17,11
               ; 4+3
               MT       0,K1,d3
               neg.l    d3
               MT_ADD   1,K4
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W32      d3,13,7
               W32      d4,16,10
               ; 5+3
               M3       0,K0,d3
               neg.l    d3
               M3_SUB   2,K2
               M3_SUB   3,K3
               M3_SUB   5,K5
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W32      d3,14,8
               W32      d4,15,9

               ; STEP 2
               addq.l   #2,a0    ; in++;

               ; Calc s[0..1],  t[0..1]
               ;
               M3       1,K1,d3
               M3_ADD   4,K4
               move.l   d3,0*4(a4) ; s[ 0 ] = M3( 1, K1 ) + M3( 4, K4 )
               M3       1,K4,d3
               M3_SUB   4,K1
               move.l   d3,1*4(a4) ; s[ 1 ] = M3( 1, K4 ) - M3( 4, K1 )

               move.w   0*6(a0),d3
               sub.w    3*6(a0),d3
               ext.l    d3
               move.l   d3,0*4(a3) ; t[ 0 ] =  x[0*3] - x[3*3]
               move.w   2*6(a0),d3
               add.w    5*6(a0),d3
               ext.l    d3
               move.l   d3,1*4(a3) ; t[ 1 ] =  x[2*3] + x[5*3]

               ; 0
               M3       0,K3,d3
               M3_SUB   2,K5
               M3_ADD   3,K0
               M3_SUB   5,K2
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W33      d3,12,0
               W33      d4,17,5
               ; 1
               MT       0,K4,d3
               MT_ADD   1,K1
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W33      d3,13,1
               W33      d4,16,4
               ; 2
               M3       0,K5,d3
               M3_ADD   2,K3
               M3_SUB   3,K2
               M3_SUB   5,K0
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W33      d3,14,2
               W33      d4,15,3

               ; 3+3
               M3       0,K2,d3
               neg.l    d3
               M3_ADD   2,K0
               M3_ADD   3,K5
               M3_SUB   5,K3
               add.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,0,6
               W34      d4,5,11
               ; 4+3
               MT       0,K1,d3
               neg.l    d3
               MT_ADD   1,K4
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,1,7
               W34      d4,4,10
               ; 5+3
               M3       0,K0,d3
               neg.l    d3
               M3_SUB   2,K2
               M3_SUB   3,K3
               M3_SUB   5,K5
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,2,8
               W34      d4,3,9

               ; STEP 3
               addq.l   #2,a0    ; in++;

               ; Calc s[0..1],  t[0..1]
               ;
               M3       1,K1,d3
               M3_ADD   4,K4
               move.l   d3,0*4(a4) ; s[ 0 ] = M3( 1, K1 ) + M3( 4, K4 )
               M3       1,K4,d3
               M3_SUB   4,K1
               move.l   d3,1*4(a4) ; s[ 1 ] = M3( 1, K4 ) - M3( 4, K1 )

               move.w   0*6(a0),d3
               sub.w    3*6(a0),d3
               ext.l    d3
               move.l   d3,0*4(a3) ; t[ 0 ] =  x[0*3] - x[3*3]
               move.w   2*6(a0),d3
               add.w    5*6(a0),d3
               ext.l    d3
               move.l   d3,1*4(a3) ; t[ 1 ] =  x[2*3] + x[5*3]

               ; 0
               M3       0,K3,d3
               M3_SUB   2,K5
               M3_ADD   3,K0
               M3_SUB   5,K2
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W35      d3,0,0
               W35      d4,5,5
               ; 1
               MT       0,K4,d3
               MT_ADD   1,K1
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W35      d3,1,1
               W35      d4,4,4
               ; 2
               M3       0,K5,d3
               M3_ADD   2,K3
               M3_SUB   3,K2
               M3_SUB   5,K0
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               neg.l    d4
               W35      d3,2,2
               W35      d4,3,3

               ; 3+3
               M3       0,K2,d3
               neg.l    d3
               M3_ADD   2,K0
               M3_ADD   3,K5
               M3_SUB   5,K3
               add.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,6,6
               W34      d4,11,11
               ; 4+3
               MT       0,K1,d3
               neg.l    d3
               MT_ADD   1,K4
               sub.l    1*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,7,7
               W34      d4,10,10
               ; 5+3
               M3       0,K0,d3
               neg.l    d3
               M3_SUB   2,K2
               M3_SUB   3,K3
               M3_SUB   5,K5
               sub.l    0*4(a4),d3
               IMDCT_FIX d3
               move.l   d3,d4
               W34      d3,8,8
               W34      d4,9,9

               subq.l   #4,a0    ; in -=2 (restore in)
               move.l   a5,a3

               unlk     a6

               rts

imdct_win0     dc.w     715, 2139, 3546, 4927, 6270, 7565
               dc.w     8803, 9974, 11069, 12080, 12998, 13818
               dc.w     14533, 15137, 15626, 15996, 16244, 16368
               dc.w     16368, 16244, 15996, 15626, 15137, 14533
               dc.w     13818, 12998, 12080, 11069, 9974, 8803
               dc.w     7565, 6270, 4927, 3546, 2139, 715
imdct_win0_odd dc.w     715, -2139, 3546, -4927, 6270, -7565
               dc.w     8803, -9974, 11069, -12080, 12998, -13818
               dc.w     14533, -15137, 15626, -15996, 16244, -16368
               dc.w     16368, -16244, 15996, -15626, 15137, -14533
               dc.w     13818, -12998, 12080, -11069, 9974, -8803
               dc.w     7565, -6270, 4927, -3546, 2139, -715

imdct_win1     dc.w     715, 2139, 3546, 4927, 6270, 7565
               dc.w     8803, 9974, 11069, 12080, 12998, 13818
               dc.w     14533, 15137, 15626, 15996, 16244, 16368
               dc.w     16384, 16384, 16384, 16384, 16384, 16384
               dc.w     16244, 15137, 12998, 9974, 6270, 2139
               dc.w     0, 0, 0, 0, 0, 0
imdct_win1_odd dc.w     715, -2139, 3546, -4927, 6270, -7565
               dc.w     8803, -9974, 11069, -12080, 12998, -13818
               dc.w     14533, -15137, 15626, -15996, 16244, -16368
               dc.w     16384, -16384, 16384, -16384, 16384, -16384
               dc.w     16244, -15137, 12998, -9974, 6270, -2139
               dc.w     0, 0, 0, 0, 0, 0

imdct_win3     dc.w     0, 0, 0, 0, 0, 0
               dc.w     2139, 6270, 9974, 12998, 15137, 16244
               dc.w     16384, 16384, 16384, 16384, 16384, 16384
               dc.w     16368, 16244, 15996, 15626, 15137, 14533
               dc.w     13818, 12998, 12080, 11069, 9974, 8803
               dc.w     7565, 6270, 4927, 3546, 2139, 715
imdct_win3_odd dc.w     0, 0, 0, 0, 0, 0
               dc.w     2139, -6270, 9974, -12998, 15137, -16244
               dc.w     16384, -16384, 16384, -16384, 16384, -16384
               dc.w     16368, -16244, 15996, -15626, 15137, -14533
               dc.w     13818, -12998, 12080, -11069, 9974, -8803
               dc.w     7565, -6270, 4927, -3546, 2139, -715

imdct_win2     dc.w     2139, 6270, 9974, 12998, 15137, 16244
               dc.w     16244, 15137, 12998, 9974, 6270, 2139
imdct_win2_odd dc.w     2139, -6270, 9974, -12998, 15137, -16244
               dc.w     16244, -15137, 12998, -9974, 6270, -2139

imdct_win      dc.l     imdct_win0
               dc.l     imdct_win1
               dc.l     imdct_win2
               dc.l     imdct_win3

imdct_win_odd  dc.l     imdct_win0_odd
               dc.l     imdct_win1_odd
               dc.l     imdct_win2_odd
               dc.l     imdct_win3_odd