2007-10-16 22:55:40 +00:00
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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2007-10-17 10:06:29 +00:00
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* $Id$
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2007-10-16 22:55:40 +00:00
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*
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* Copyright (C) 2007 Jens Arnold
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* Based on the work of Karim Boucher and Rani Hod
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*
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2008-06-28 18:10:04 +00:00
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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2007-10-16 22:55:40 +00:00
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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2007-12-07 13:00:31 +00:00
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.global mpeg2_idct_copy
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.type mpeg2_idct_copy, @function
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.global mpeg2_idct_add
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.type mpeg2_idct_add, @function
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2007-10-16 22:55:40 +00:00
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/* The IDCT itself.
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* Input: %a0: block pointer
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2007-10-18 00:14:22 +00:00
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* Caller must save all registers. */
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2007-10-16 22:55:40 +00:00
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.align 2
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.idct:
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move.l %a0, %a6
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move.l #0, %macsr | signed integer mode
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move.l #((2048<<16)+2841), %a0 | W0, W1
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move.l #((2676<<16)+2408), %a1 | W2, W3
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move.l #((2048<<16)+1609), %a2 | W4, W5
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move.l #((1108<<16)+ 565), %a3 | W6, W7
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lea.l (128,%a6), %a4 | secondary, transposed temp buffer
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moveq.l #8, %d3 | loop counter
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.row_loop:
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movem.l (%a6), %d0-%d2/%a5 | fetch (f0, f2, f4, f6, f1, f3, f5, f7)
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mac.w %a0l, %d2u, %acc0 | %acc0 = W1 * f1
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mac.w %a1l, %d2l, %acc0 | + W3 * f3
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mac.w %a2l, %a5u, %acc0 | + W5 * f5
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mac.w %a3l, %a5l, %acc0 | + W7 * f7
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mac.w %a1l, %d2u, %acc1 | %acc1 = W3 * f1
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msac.w %a3l, %d2l, %acc1 | - W7 * f3
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msac.w %a0l, %a5u, %acc1 | - W1 * f5
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msac.w %a2l, %a5l, %acc1 | - W5 * f7
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mac.w %a2l, %d2u, %acc2 | %acc2 = W5 * f1
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msac.w %a0l, %d2l, %acc2 | - W1 * f3
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mac.w %a3l, %a5u, %acc2 | + W7 * f5
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mac.w %a1l, %a5l, %acc2 | + W3 * f7
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mac.w %a3l, %d2u, %acc3 | %acc3 = W7 * f1
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msac.w %a2l, %d2l, %acc3 | - W5 * f3
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mac.w %a1l, %a5u, %acc3 | + W3 * f5
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msac.w %a0l, %a5l, %acc3 | - W1 * f7
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lea.l (16,%a6), %a6 | Advance to next row; put here to fill EMAC latency
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add.l #(1<<16), %d0 | f0 += 1;
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movclr.l %acc0, %d4 | b0
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movclr.l %acc1, %d5 | b1
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movclr.l %acc2, %d6 | b2
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movclr.l %acc3, %d7 | b3
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mac.w %a0u, %d0u, %acc0 | %acc0 = W0 * f0
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mac.w %a2u, %d1u, %acc0 | + W4 * f4
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move.l %acc0, %acc3
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mac.w %a1u, %d0l, %acc0 | + W2 * f2
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mac.w %a3u, %d1l, %acc0 | + W6 * f6
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mac.w %a0u, %d0u, %acc1 | %acc1 = W0 * f0
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msac.w %a2u, %d1u, %acc1 | - W4 * f4
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move.l %acc1, %acc2
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mac.w %a3u, %d0l, %acc1 | + W6 * f2
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msac.w %a1u, %d1l, %acc1 | - W2 * f6
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2007-10-21 07:42:32 +00:00
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| ^ move.l %acc1, %acc2 %acc2 = W0 * f0 - W4 * f4
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2007-10-16 22:55:40 +00:00
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msac.w %a3u, %d0l, %acc2 | - W6 * f2
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mac.w %a1u, %d1l, %acc2 | + W2 * f6
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2007-10-21 07:42:32 +00:00
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| ^ move.l %acc0, %acc3 %acc3 = W0 * f0 + W4 * f4
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2007-10-16 22:55:40 +00:00
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msac.w %a1u, %d0l, %acc3 | - W2 * f2
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msac.w %a3u, %d1l, %acc3 | - W6 * f6
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moveq.l #12, %d1 | shift amount
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move.l %acc0, %d0 | block[7] = (a0
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sub.l %d4,%d0 | - b0)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (7*16,%a4)
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move.l %acc1, %d0 | block[6] = (a1
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sub.l %d5,%d0 | - b1)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (6*16,%a4)
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move.l %acc2, %d0 | block[5] = (a2
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sub.l %d6,%d0 | - b2)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (5*16,%a4)
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move.l %acc3, %d0 | block[4] = (a3
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sub.l %d7,%d0 | - b3)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (4*16,%a4)
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movclr.l %acc3, %d0 | block[3] = (a3
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add.l %d7, %d0 | + b3)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (3*16,%a4)
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movclr.l %acc2, %d0 | block[2] = (a2
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add.l %d6, %d0 | + b2)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (2*16,%a4)
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movclr.l %acc1, %d0 | block[1] = (a1
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add.l %d5, %d0 | + b1)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (1*16,%a4)
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movclr.l %acc0, %d0 | block[0] = (a0
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add.l %d4, %d0 | + b0)
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asr.l %d1, %d0 | >> 12
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move.w %d0, (%a4)+ | advance to next temp column
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subq.l #1, %d3 | loop 8 times
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bne.w .row_loop
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| %a6 now points to the temp buffer, where we need it.
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lea.l (-16-128,%a4), %a4 | point %a4 back to the input block
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moveq.l #8, %d3 | loop counter
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.col_loop:
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movem.l (%a6), %d0-%d2/%a5 | fetch (f0, f2, f4, f6, f1, f3, f5, f7)
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mac.w %a0l, %d2u, %acc0 | %acc0 = W1 * f1
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mac.w %a1l, %d2l, %acc0 | + W3 * f3
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mac.w %a2l, %a5u, %acc0 | + W5 * f5
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mac.w %a3l, %a5l, %acc0 | + W7 * f7
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mac.w %a1l, %d2u, %acc1 | %acc1 = W3 * f1
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msac.w %a3l, %d2l, %acc1 | - W7 * f3
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msac.w %a0l, %a5u, %acc1 | - W1 * f5
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msac.w %a2l, %a5l, %acc1 | - W5 * f7
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mac.w %a2l, %d2u, %acc2 | %acc2 = W5 * f1
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msac.w %a0l, %d2l, %acc2 | - W1 * f3
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mac.w %a3l, %a5u, %acc2 | + W7 * f5
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mac.w %a1l, %a5l, %acc2 | + W3 * f7
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mac.w %a3l, %d2u, %acc3 | %acc3 = W7 * f1
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msac.w %a2l, %d2l, %acc3 | - W5 * f3
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mac.w %a1l, %a5u, %acc3 | + W3 * f5
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msac.w %a0l, %a5l, %acc3 | - W1 * f7
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lea.l (16,%a6), %a6 | Advance to next row; put here to fill EMAC latency
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add.l #(32<<16), %d0 | DC offset: 0.5
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movclr.l %acc0, %d4 | b0
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movclr.l %acc1, %d5 | b1
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movclr.l %acc2, %d6 | b2
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movclr.l %acc3, %d7 | b3
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mac.w %a0u, %d0u, %acc0 | %acc0 = W0 * f0
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mac.w %a2u, %d1u, %acc0 | + W4 * f4
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move.l %acc0, %acc3
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mac.w %a1u, %d0l, %acc0 | + W2 * f2
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mac.w %a3u, %d1l, %acc0 | + W6 * f6
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mac.w %a0u, %d0u, %acc1 | %acc1 = W0 * f0
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msac.w %a2u, %d1u, %acc1 | - W4 * f4
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move.l %acc1, %acc2
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mac.w %a3u, %d0l, %acc1 | + W6 * f2
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msac.w %a1u, %d1l, %acc1 | - W2 * f6
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| ^ move.l %acc1, %acc2 %acc2 = W0 * f0 - W4 * f4
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msac.w %a3u, %d0l, %acc2 | - W6 * f2
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mac.w %a1u, %d1l, %acc2 | + W2 * f6
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| ^ move.l %acc0, %acc3 %acc3 = W0 * f0 + W4 * f4
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msac.w %a1u, %d0l, %acc3 | - W2 * f2
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msac.w %a3u, %d1l, %acc3 | - W6 * f6
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moveq.l #17, %d1 | shift amount
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move.l %acc0, %d0 | block[7] = (a0
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sub.l %d4,%d0 | - b0)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (7*16,%a4)
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move.l %acc1, %d0 | block[6] = (a1
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sub.l %d5,%d0 | - b1)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (6*16,%a4)
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move.l %acc2, %d0 | block[5] = (a2
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sub.l %d6,%d0 | - b2)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (5*16,%a4)
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move.l %acc3, %d0 | block[4] = (a3
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sub.l %d7,%d0 | - b3)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (4*16,%a4)
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movclr.l %acc3, %d0 | block[3] = (a3
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add.l %d7, %d0 | + b3)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (3*16,%a4)
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movclr.l %acc2, %d0 | block[2] = (a2
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add.l %d6, %d0 | + b2)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (2*16,%a4)
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movclr.l %acc1, %d0 | block[1] = (a1
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add.l %d5, %d0 | + b1)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (1*16,%a4)
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movclr.l %acc0, %d0 | block[0] = (a0
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add.l %d4, %d0 | + b0)
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asr.l %d1, %d0 | >> 17
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move.w %d0, (%a4)+ | advance to next column
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subq.l #1, %d3 | loop 8 times
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bne.w .col_loop
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rts
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.align 2
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2007-12-07 13:00:31 +00:00
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mpeg2_idct_copy:
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2007-10-18 00:14:22 +00:00
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lea.l (-11*4,%sp), %sp
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movem.l %d2-%d7/%a2-%a6, (%sp) | save some registers
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move.l (11*4+4,%sp), %a0 | %a0 - block pointer for idct
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2007-10-16 22:55:40 +00:00
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2007-10-18 00:14:22 +00:00
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bsr.w .idct | apply idct to block
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movem.l (11*4+4,%sp), %a0-%a2 | %a0 - block pointer
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| %a1 - destination pointer
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| %a2 - stride
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2007-10-16 22:55:40 +00:00
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move.l #255, %d1 | preload constant for clipping
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moveq.l #8, %d4 | loop counter
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.copy_clip_loop:
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move.w (%a0), %d0 | load block[0]
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ext.l %d0 | sign extend
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cmp.l %d1, %d0 | overflow?
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bls.b 1f
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spl.b %d0 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d2 | collect output bytes 0..3 in %d2
|
|
|
|
|
lsl.l #8, %d2
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0 | load block[1]
|
|
|
|
|
ext.l %d0 | sign extend
|
|
|
|
|
cmp.l %d1, %d0 | overflow?
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d2 | collect output bytes 0..3 in %d2
|
|
|
|
|
lsl.l #8, %d2
|
|
|
|
|
clr.l (%a0)+ | clear block[0] and block[1],
|
|
|
|
|
| %a0 now pointing to block[2]
|
|
|
|
|
move.w (%a0), %d0 | do b2 and b3
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d2
|
|
|
|
|
lsl.l #8, %d2
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d2
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
move.w (%a0), %d0 | do b4 and b5
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d3
|
|
|
|
|
lsl.l #8, %d3
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d3
|
|
|
|
|
lsl.l #8, %d3
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
move.w (%a0), %d0 | do b6 and b7
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d3
|
|
|
|
|
lsl.l #8, %d3
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0
|
|
|
|
|
ext.l %d0
|
|
|
|
|
cmp.l %d1, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.b %d0, %d3
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
movem.l %d2-%d3, (%a1) | write all 8 output bytes at once
|
2007-10-21 07:42:32 +00:00
|
|
|
add.l %a2, %a1 | advance output pointer
|
2007-10-16 22:55:40 +00:00
|
|
|
subq.l #1, %d4 | loop 8 times
|
|
|
|
|
bne.w .copy_clip_loop
|
|
|
|
|
|
2007-10-18 00:14:22 +00:00
|
|
|
movem.l (%sp), %d2-%d7/%a2-%a6
|
|
|
|
|
lea.l (11*4,%sp), %sp
|
2007-10-16 22:55:40 +00:00
|
|
|
rts
|
|
|
|
|
|
|
|
|
|
.align 2
|
|
|
|
|
|
2007-12-07 13:00:31 +00:00
|
|
|
mpeg2_idct_add:
|
2007-10-18 00:14:22 +00:00
|
|
|
lea.l (-11*4,%sp), %sp
|
|
|
|
|
movem.l %d2-%d7/%a2-%a6, (%sp)
|
|
|
|
|
movem.l (11*4+4,%sp), %d0/%a0-%a2 | %d0 - last value
|
|
|
|
|
| %a0 - block pointer
|
|
|
|
|
| %a1 - destination pointer
|
|
|
|
|
| %a2 - stride
|
|
|
|
|
|
2007-10-16 22:55:40 +00:00
|
|
|
cmp.l #129, %d0 | last == 129 ?
|
|
|
|
|
bne.b .idct_add | no: perform idct + addition
|
2007-10-18 00:14:22 +00:00
|
|
|
move.w (%a0), %d0
|
2007-10-16 22:55:40 +00:00
|
|
|
ext.l %d0 | ((block[0]
|
|
|
|
|
asr.l #4, %d0 | >> 4)
|
|
|
|
|
and.l #7, %d0 | & 7)
|
|
|
|
|
subq.l #4, %d0 | - 4 == 0 ?
|
|
|
|
|
bne.w .dc_add | no: just perform addition
|
|
|
|
|
|
|
|
|
|
.idct_add:
|
2007-10-18 00:14:22 +00:00
|
|
|
bsr.w .idct | apply idct
|
|
|
|
|
movem.l (11*4+8,%sp), %a0-%a2 | reload arguments %a0..%a2
|
|
|
|
|
|
2007-10-16 22:55:40 +00:00
|
|
|
move.l #255, %d2 | preload constant for clipping
|
|
|
|
|
clr.l %d3 | used for splitting input words into bytes
|
|
|
|
|
moveq.l #8, %d4 | loop counter
|
|
|
|
|
|
|
|
|
|
.add_clip_loop:
|
|
|
|
|
movem.l (%a1), %d6-%d7 | fetch (b0 b1 b2 b3) (b4 b5 b6 b7)
|
|
|
|
|
swap %d6 | (b2 b3 b0 b1)
|
|
|
|
|
swap %d7 | (b6 b7 b4 b5)
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0 | load block[1]
|
|
|
|
|
ext.l %d0 | sign extend
|
|
|
|
|
move.b %d6, %d3 | copy b1
|
|
|
|
|
lsr.l #8, %d6 | prepare 1st buffer for next byte
|
|
|
|
|
add.l %d3, %d0 | add b1
|
|
|
|
|
cmp.l %d2, %d0 | overflow ?
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.w (%a0), %d1 | load block[0]
|
|
|
|
|
ext.l %d1 | sign extend
|
|
|
|
|
move.b %d6, %d3 | copy b0
|
|
|
|
|
lsr.l #8, %d6 | prepare 1st buffer for next byte
|
|
|
|
|
add.l %d3, %d1 | add b0
|
|
|
|
|
cmp.l %d2, %d1 | overflow ?
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d5 | collect output bytes 0..3 in %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
move.b %d0, %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
clr.l (%a0)+ | clear block[0] and block[1]
|
|
|
|
|
| %a0 now pointing to block[2]
|
|
|
|
|
move.w (2,%a0), %d0 | do b3 and b2
|
|
|
|
|
ext.l %d0
|
|
|
|
|
move.b %d6, %d3
|
|
|
|
|
lsr.l #8, %d6
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.w (%a0), %d1
|
|
|
|
|
ext.l %d1
|
|
|
|
|
add.l %d6, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
move.b %d0, %d5
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0 | do b5 and b4
|
|
|
|
|
ext.l %d0
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.w (%a0), %d1
|
|
|
|
|
ext.l %d1
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
move.b %d0, %d6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
move.w (2,%a0), %d0 | do b7 and b6
|
|
|
|
|
ext.l %d0
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.w (%a0), %d1
|
|
|
|
|
ext.l %d1
|
|
|
|
|
add.l %d7, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
move.b %d0, %d6
|
|
|
|
|
clr.l (%a0)+
|
|
|
|
|
|
|
|
|
|
movem.l %d5-%d6, (%a1) | write all 8 output bytes at once
|
2007-10-21 07:42:32 +00:00
|
|
|
add.l %a2, %a1 | advance output pointer
|
2007-10-16 22:55:40 +00:00
|
|
|
subq.l #1, %d4 | loop 8 times
|
|
|
|
|
bne.w .add_clip_loop
|
|
|
|
|
|
|
|
|
|
bra.w .idct_add_end
|
|
|
|
|
|
|
|
|
|
.dc_add:
|
|
|
|
|
move.w (%a0), %d0
|
|
|
|
|
ext.l %d0 | %d0 = (block[0]
|
|
|
|
|
add.l #64, %d0 | + 64)
|
|
|
|
|
asr.l #7, %d0 | >> 7
|
|
|
|
|
clr.w (%a0) | clear block[0]
|
|
|
|
|
clr.w (63*2,%a0) | and block[63]
|
|
|
|
|
move.l %d0, %a0 | DC value in %a0
|
|
|
|
|
|
|
|
|
|
move.l #255, %d2 | preload constant for clipping
|
|
|
|
|
clr.l %d3 | for splitting input words into bytes
|
|
|
|
|
moveq.l #8, %d4 | loop counter
|
|
|
|
|
|
|
|
|
|
.dc_clip_loop:
|
|
|
|
|
movem.l (%a1), %d6-%d7 | (b0 b1 b2 b3) (b4 b5 b6 b7)
|
|
|
|
|
swap %d6 | (b2 b3 b0 b1)
|
|
|
|
|
swap %d7 | (b6 b7 b4 b5)
|
|
|
|
|
|
|
|
|
|
move.l %a0, %d0 | copy DC
|
|
|
|
|
move.b %d6, %d3 | copy b1
|
|
|
|
|
lsr.l #8, %d6 | prepare 1st buffer for next byte
|
|
|
|
|
add.l %d3, %d0 | add b1
|
|
|
|
|
cmp.l %d2, %d0 | overflow ?
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.l %a0, %d1 | copy DC
|
|
|
|
|
move.b %d6, %d3 | copy b0
|
|
|
|
|
lsr.l #8, %d6 | prepare 1st buffer for next byte
|
|
|
|
|
add.l %d3, %d1 | add b0
|
|
|
|
|
cmp.l %d2, %d1 | overflow ?
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1 | yes: set appropriate limit value in low byte
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d5 | collect output bytes 0..3 in %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
move.b %d0, %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
|
|
|
|
|
move.l %a0, %d0 | do b3 and b2
|
|
|
|
|
move.b %d6, %d3
|
|
|
|
|
lsr.l #8, %d6
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.l %a0, %d1
|
|
|
|
|
add.l %d6, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d5
|
|
|
|
|
lsl.l #8, %d5
|
|
|
|
|
move.b %d0, %d5
|
|
|
|
|
|
|
|
|
|
move.l %a0, %d0 | do b5 and b4
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.l %a0, %d1
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d6 | do b7 and b6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
move.b %d0, %d6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
|
|
|
|
|
move.l %a0, %d0
|
|
|
|
|
move.b %d7, %d3
|
|
|
|
|
lsr.l #8, %d7
|
|
|
|
|
add.l %d3, %d0
|
|
|
|
|
cmp.l %d2, %d0
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d0
|
|
|
|
|
1:
|
|
|
|
|
move.l %a0, %d1
|
|
|
|
|
add.l %d7, %d1
|
|
|
|
|
cmp.l %d2, %d1
|
|
|
|
|
bls.b 1f
|
|
|
|
|
spl.b %d1
|
|
|
|
|
1:
|
|
|
|
|
move.b %d1, %d6
|
|
|
|
|
lsl.l #8, %d6
|
|
|
|
|
move.b %d0, %d6
|
|
|
|
|
|
|
|
|
|
movem.l %d5-%d6, (%a1) | write all 8 output bytes at once
|
2007-10-21 07:42:32 +00:00
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add.l %a2, %a1 | advance output pointer
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2007-10-16 22:55:40 +00:00
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subq.l #1, %d4 | loop 8 times
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bne.w .dc_clip_loop
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.idct_add_end:
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2007-10-18 00:14:22 +00:00
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movem.l (%sp), %d2-%d7/%a2-%a6
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lea.l (11*4,%sp), %sp
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2007-10-16 22:55:40 +00:00
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rts
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