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https://github.com/FFmpeg/FFmpeg.git
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406792e7b0
Originally committed as revision 16684 to svn://svn.ffmpeg.org/ffmpeg/trunk
487 lines
22 KiB
ArmAsm
487 lines
22 KiB
ArmAsm
/*
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* simple_idct_arm.S
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* Copyright (C) 2002 Frederic 'dilb' Boulay
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*
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* Author: Frederic Boulay <dilb@handhelds.org>
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*
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* The function defined in this file is derived from the simple_idct function
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* from the libavcodec library part of the FFmpeg project.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "asm.S"
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/* useful constants for the algorithm, they are save in __constant_ptr__ at */
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/* the end of the source code.*/
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#define W1 22725
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#define W2 21407
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#define W3 19266
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#define W4 16383
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#define W5 12873
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#define W6 8867
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#define W7 4520
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#define MASK_MSHW 0xFFFF0000
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/* offsets of the constants in the vector */
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#define offW1 0
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#define offW2 4
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#define offW3 8
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#define offW4 12
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#define offW5 16
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#define offW6 20
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#define offW7 24
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#define offMASK_MSHW 28
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#define ROW_SHIFT 11
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#define ROW_SHIFT2MSHW (16-11)
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#define COL_SHIFT 20
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#define ROW_SHIFTED_1 1024 /* 1<< (ROW_SHIFT-1) */
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#define COL_SHIFTED_1 524288 /* 1<< (COL_SHIFT-1) */
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.text
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function simple_idct_ARM, export=1
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@@ void simple_idct_ARM(int16_t *block)
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@@ save stack for reg needed (take all of them),
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@@ R0-R3 are scratch regs, so no need to save them, but R0 contains the pointer to block
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@@ so it must not be overwritten, if it is not saved!!
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@@ R12 is another scratch register, so it should not be saved too
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@@ save all registers
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stmfd sp!, {r4-r11, r14} @ R14 is also called LR
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@@ at this point, R0=block, other registers are free.
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add r14, r0, #112 @ R14=&block[8*7], better start from the last row, and decrease the value until row=0, i.e. R12=block.
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add r12, pc, #(__constant_ptr__-.-8) @ R12=__constant_ptr__, the vector containing the constants, probably not necessary to reserve a register for it
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@@ add 2 temporary variables in the stack: R0 and R14
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sub sp, sp, #8 @ allow 2 local variables
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str r0, [sp, #0] @ save block in sp[0]
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@@ stack status
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@@ sp+4 free
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@@ sp+0 R0 (block)
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@@ at this point, R0=block, R14=&block[56], R12=__const_ptr_, R1-R11 free
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__row_loop:
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@@ read the row and check if it is null, almost null, or not, according to strongarm specs, it is not necessary to optimize ldr accesses (i.e. split 32bits in 2 16bits words), at least it gives more usable registers :)
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ldr r1, [r14, #0] @ R1=(int32)(R12)[0]=ROWr32[0] (relative row cast to a 32b pointer)
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ldr r2, [r14, #4] @ R2=(int32)(R12)[1]=ROWr32[1]
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ldr r3, [r14, #8] @ R3=ROWr32[2]
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ldr r4, [r14, #12] @ R4=ROWr32[3]
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@@ check if the words are null, if all of them are null, then proceed with next row (branch __end_row_loop),
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@@ if ROWr16[0] is the only one not null, then proceed with this special case (branch __almost_empty_row)
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@@ else follow the complete algorithm.
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@@ at this point, R0=block, R14=&block[n], R12=__const_ptr_, R1=ROWr32[0], R2=ROWr32[1],
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@@ R3=ROWr32[2], R4=ROWr32[3], R5-R11 free
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orr r5, r4, r3 @ R5=R4 | R3
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orr r5, r5, r2 @ R5=R4 | R3 | R2
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orrs r6, r5, r1 @ Test R5 | R1 (the aim is to check if everything is null)
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beq __end_row_loop
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mov r7, r1, asr #16 @ R7=R1>>16=ROWr16[1] (evaluate it now, as it could be useful later)
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ldrsh r6, [r14, #0] @ R6=ROWr16[0]
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orrs r5, r5, r7 @ R5=R4 | R3 | R2 | R7
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beq __almost_empty_row
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__b_evaluation:
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@@ at this point, R0=block (temp), R1(free), R2=ROWr32[1], R3=ROWr32[2], R4=ROWr32[3],
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@@ R5=(temp), R6=ROWr16[0], R7=ROWr16[1], R8-R11 free,
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@@ R12=__const_ptr_, R14=&block[n]
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@@ to save some registers/calls, proceed with b0-b3 first, followed by a0-a3
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@@ MUL16(b0, W1, row[1]);
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@@ MUL16(b1, W3, row[1]);
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@@ MUL16(b2, W5, row[1]);
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@@ MUL16(b3, W7, row[1]);
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@@ MAC16(b0, W3, row[3]);
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@@ MAC16(b1, -W7, row[3]);
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@@ MAC16(b2, -W1, row[3]);
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@@ MAC16(b3, -W5, row[3]);
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ldr r8, [r12, #offW1] @ R8=W1
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mov r2, r2, asr #16 @ R2=ROWr16[3]
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mul r0, r8, r7 @ R0=W1*ROWr16[1]=b0 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
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ldr r9, [r12, #offW3] @ R9=W3
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ldr r10, [r12, #offW5] @ R10=W5
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mul r1, r9, r7 @ R1=W3*ROWr16[1]=b1 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
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ldr r11, [r12, #offW7] @ R11=W7
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mul r5, r10, r7 @ R5=W5*ROWr16[1]=b2 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
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mul r7, r11, r7 @ R7=W7*ROWr16[1]=b3 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
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teq r2, #0 @ if null avoid muls
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mlane r0, r9, r2, r0 @ R0+=W3*ROWr16[3]=b0 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
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rsbne r2, r2, #0 @ R2=-ROWr16[3]
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mlane r1, r11, r2, r1 @ R1-=W7*ROWr16[3]=b1 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
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mlane r5, r8, r2, r5 @ R5-=W1*ROWr16[3]=b2 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
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mlane r7, r10, r2, r7 @ R7-=W5*ROWr16[3]=b3 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
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@@ at this point, R0=b0, R1=b1, R2 (free), R3=ROWr32[2], R4=ROWr32[3],
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@@ R5=b2, R6=ROWr16[0], R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
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@@ R12=__const_ptr_, R14=&block[n]
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@@ temp = ((uint32_t*)row)[2] | ((uint32_t*)row)[3];
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@@ if (temp != 0) {}
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orrs r2, r3, r4 @ R2=ROWr32[2] | ROWr32[3]
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beq __end_b_evaluation
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@@ at this point, R0=b0, R1=b1, R2 (free), R3=ROWr32[2], R4=ROWr32[3],
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@@ R5=b2, R6=ROWr16[0], R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
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@@ R12=__const_ptr_, R14=&block[n]
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@@ MAC16(b0, W5, row[5]);
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@@ MAC16(b2, W7, row[5]);
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@@ MAC16(b3, W3, row[5]);
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@@ MAC16(b1, -W1, row[5]);
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@@ MAC16(b0, W7, row[7]);
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@@ MAC16(b2, W3, row[7]);
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@@ MAC16(b3, -W1, row[7]);
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@@ MAC16(b1, -W5, row[7]);
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mov r3, r3, asr #16 @ R3=ROWr16[5]
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teq r3, #0 @ if null avoid muls
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mlane r0, r10, r3, r0 @ R0+=W5*ROWr16[5]=b0
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mov r4, r4, asr #16 @ R4=ROWr16[7]
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mlane r5, r11, r3, r5 @ R5+=W7*ROWr16[5]=b2
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mlane r7, r9, r3, r7 @ R7+=W3*ROWr16[5]=b3
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rsbne r3, r3, #0 @ R3=-ROWr16[5]
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mlane r1, r8, r3, r1 @ R7-=W1*ROWr16[5]=b1
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@@ R3 is free now
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teq r4, #0 @ if null avoid muls
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mlane r0, r11, r4, r0 @ R0+=W7*ROWr16[7]=b0
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mlane r5, r9, r4, r5 @ R5+=W3*ROWr16[7]=b2
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rsbne r4, r4, #0 @ R4=-ROWr16[7]
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mlane r7, r8, r4, r7 @ R7-=W1*ROWr16[7]=b3
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mlane r1, r10, r4, r1 @ R1-=W5*ROWr16[7]=b1
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@@ R4 is free now
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__end_b_evaluation:
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@@ at this point, R0=b0, R1=b1, R2=ROWr32[2] | ROWr32[3] (tmp), R3 (free), R4 (free),
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@@ R5=b2, R6=ROWr16[0], R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
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@@ R12=__const_ptr_, R14=&block[n]
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__a_evaluation:
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@@ a0 = (W4 * row[0]) + (1 << (ROW_SHIFT - 1));
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@@ a1 = a0 + W6 * row[2];
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@@ a2 = a0 - W6 * row[2];
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@@ a3 = a0 - W2 * row[2];
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@@ a0 = a0 + W2 * row[2];
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ldr r9, [r12, #offW4] @ R9=W4
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mul r6, r9, r6 @ R6=W4*ROWr16[0]
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ldr r10, [r12, #offW6] @ R10=W6
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ldrsh r4, [r14, #4] @ R4=ROWr16[2] (a3 not defined yet)
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add r6, r6, #ROW_SHIFTED_1 @ R6=W4*ROWr16[0] + 1<<(ROW_SHIFT-1) (a0)
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mul r11, r10, r4 @ R11=W6*ROWr16[2]
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ldr r8, [r12, #offW2] @ R8=W2
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sub r3, r6, r11 @ R3=a0-W6*ROWr16[2] (a2)
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@@ temp = ((uint32_t*)row)[2] | ((uint32_t*)row)[3];
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@@ if (temp != 0) {}
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teq r2, #0
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beq __end_bef_a_evaluation
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add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
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mul r11, r8, r4 @ R11=W2*ROWr16[2]
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sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
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add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
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@@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
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@@ R5=b2, R6=a0, R7=b3, R8=W2, R9=W4, R10=W6, R11 (free),
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@@ R12=__const_ptr_, R14=&block[n]
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@@ a0 += W4*row[4]
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@@ a1 -= W4*row[4]
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@@ a2 -= W4*row[4]
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@@ a3 += W4*row[4]
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ldrsh r11, [r14, #8] @ R11=ROWr16[4]
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teq r11, #0 @ if null avoid muls
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mulne r11, r9, r11 @ R11=W4*ROWr16[4]
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@@ R9 is free now
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ldrsh r9, [r14, #12] @ R9=ROWr16[6]
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addne r6, r6, r11 @ R6+=W4*ROWr16[4] (a0)
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subne r2, r2, r11 @ R2-=W4*ROWr16[4] (a1)
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subne r3, r3, r11 @ R3-=W4*ROWr16[4] (a2)
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addne r4, r4, r11 @ R4+=W4*ROWr16[4] (a3)
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@@ W6 alone is no more useful, save W2*ROWr16[6] in it instead
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teq r9, #0 @ if null avoid muls
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mulne r11, r10, r9 @ R11=W6*ROWr16[6]
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addne r6, r6, r11 @ R6+=W6*ROWr16[6] (a0)
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mulne r10, r8, r9 @ R10=W2*ROWr16[6]
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@@ a0 += W6*row[6];
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@@ a3 -= W6*row[6];
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@@ a1 -= W2*row[6];
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@@ a2 += W2*row[6];
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subne r4, r4, r11 @ R4-=W6*ROWr16[6] (a3)
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subne r2, r2, r10 @ R2-=W2*ROWr16[6] (a1)
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addne r3, r3, r10 @ R3+=W2*ROWr16[6] (a2)
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__end_a_evaluation:
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@@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
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@@ R5=b2, R6=a0, R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
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@@ R12=__const_ptr_, R14=&block[n]
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@@ row[0] = (a0 + b0) >> ROW_SHIFT;
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@@ row[1] = (a1 + b1) >> ROW_SHIFT;
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@@ row[2] = (a2 + b2) >> ROW_SHIFT;
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@@ row[3] = (a3 + b3) >> ROW_SHIFT;
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@@ row[4] = (a3 - b3) >> ROW_SHIFT;
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@@ row[5] = (a2 - b2) >> ROW_SHIFT;
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@@ row[6] = (a1 - b1) >> ROW_SHIFT;
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@@ row[7] = (a0 - b0) >> ROW_SHIFT;
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add r8, r6, r0 @ R8=a0+b0
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add r9, r2, r1 @ R9=a1+b1
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@@ put 2 16 bits half-words in a 32bits word
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@@ ROWr32[0]=ROWr16[0] | (ROWr16[1]<<16) (only Little Endian compliant then!!!)
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ldr r10, [r12, #offMASK_MSHW] @ R10=0xFFFF0000
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and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a1+b1)<<5)
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mvn r11, r10 @ R11= NOT R10= 0x0000FFFF
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and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a0+b0)>>11)
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orr r8, r8, r9
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str r8, [r14, #0]
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add r8, r3, r5 @ R8=a2+b2
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add r9, r4, r7 @ R9=a3+b3
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and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a3+b3)<<5)
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and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a2+b2)>>11)
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orr r8, r8, r9
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str r8, [r14, #4]
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sub r8, r4, r7 @ R8=a3-b3
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sub r9, r3, r5 @ R9=a2-b2
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and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a2-b2)<<5)
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and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a3-b3)>>11)
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orr r8, r8, r9
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str r8, [r14, #8]
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sub r8, r2, r1 @ R8=a1-b1
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sub r9, r6, r0 @ R9=a0-b0
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and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a0-b0)<<5)
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and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a1-b1)>>11)
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orr r8, r8, r9
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str r8, [r14, #12]
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bal __end_row_loop
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__almost_empty_row:
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@@ the row was empty, except ROWr16[0], now, management of this special case
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@@ at this point, R0=block, R14=&block[n], R12=__const_ptr_, R1=ROWr32[0], R2=ROWr32[1],
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@@ R3=ROWr32[2], R4=ROWr32[3], R5=(temp), R6=ROWr16[0], R7=ROWr16[1],
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@@ R8=0xFFFF (temp), R9-R11 free
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mov r8, #0x10000 @ R8=0xFFFF (2 steps needed!) it saves a ldr call (because of delay run).
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sub r8, r8, #1 @ R8 is now ready.
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and r5, r8, r6, lsl #3 @ R5=R8 & (R6<<3)= (ROWr16[0]<<3) & 0xFFFF
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orr r5, r5, r5, lsl #16 @ R5=R5 | (R5<<16)
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str r5, [r14, #0] @ R14[0]=ROWr32[0]=R5
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str r5, [r14, #4] @ R14[4]=ROWr32[1]=R5
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str r5, [r14, #8] @ R14[8]=ROWr32[2]=R5
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str r5, [r14, #12] @ R14[12]=ROWr32[3]=R5
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__end_row_loop:
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@@ at this point, R0-R11 (free)
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@@ R12=__const_ptr_, R14=&block[n]
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ldr r0, [sp, #0] @ R0=block
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teq r0, r14 @ compare current &block[8*n] to block, when block is reached, the loop is finished.
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sub r14, r14, #16
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bne __row_loop
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@@ at this point, R0=block, R1-R11 (free)
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@@ R12=__const_ptr_, R14=&block[n]
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add r14, r0, #14 @ R14=&block[7], better start from the last col, and decrease the value until col=0, i.e. R14=block.
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__col_loop:
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__b_evaluation2:
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@@ at this point, R0=block (temp), R1-R11 (free)
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@@ R12=__const_ptr_, R14=&block[n]
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@@ proceed with b0-b3 first, followed by a0-a3
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@@ MUL16(b0, W1, col[8x1]);
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@@ MUL16(b1, W3, col[8x1]);
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@@ MUL16(b2, W5, col[8x1]);
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@@ MUL16(b3, W7, col[8x1]);
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@@ MAC16(b0, W3, col[8x3]);
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@@ MAC16(b1, -W7, col[8x3]);
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@@ MAC16(b2, -W1, col[8x3]);
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@@ MAC16(b3, -W5, col[8x3]);
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ldr r8, [r12, #offW1] @ R8=W1
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ldrsh r7, [r14, #16]
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mul r0, r8, r7 @ R0=W1*ROWr16[1]=b0 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
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ldr r9, [r12, #offW3] @ R9=W3
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ldr r10, [r12, #offW5] @ R10=W5
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mul r1, r9, r7 @ R1=W3*ROWr16[1]=b1 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|
ldr r11, [r12, #offW7] @ R11=W7
|
|
mul r5, r10, r7 @ R5=W5*ROWr16[1]=b2 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|
ldrsh r2, [r14, #48]
|
|
mul r7, r11, r7 @ R7=W7*ROWr16[1]=b3 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|
teq r2, #0 @ if 0, then avoid muls
|
|
mlane r0, r9, r2, r0 @ R0+=W3*ROWr16[3]=b0 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
|
|
rsbne r2, r2, #0 @ R2=-ROWr16[3]
|
|
mlane r1, r11, r2, r1 @ R1-=W7*ROWr16[3]=b1 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
|
|
mlane r5, r8, r2, r5 @ R5-=W1*ROWr16[3]=b2 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
|
|
mlane r7, r10, r2, r7 @ R7-=W5*ROWr16[3]=b3 (ROWr16[3] must be the second arg, to have the possibility to save 1 cycle)
|
|
|
|
@@ at this point, R0=b0, R1=b1, R2 (free), R3 (free), R4 (free),
|
|
@@ R5=b2, R6 (free), R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
|
|
@@ R12=__const_ptr_, R14=&block[n]
|
|
@@ MAC16(b0, W5, col[5x8]);
|
|
@@ MAC16(b2, W7, col[5x8]);
|
|
@@ MAC16(b3, W3, col[5x8]);
|
|
@@ MAC16(b1, -W1, col[5x8]);
|
|
@@ MAC16(b0, W7, col[7x8]);
|
|
@@ MAC16(b2, W3, col[7x8]);
|
|
@@ MAC16(b3, -W1, col[7x8]);
|
|
@@ MAC16(b1, -W5, col[7x8]);
|
|
ldrsh r3, [r14, #80] @ R3=COLr16[5x8]
|
|
teq r3, #0 @ if 0 then avoid muls
|
|
mlane r0, r10, r3, r0 @ R0+=W5*ROWr16[5x8]=b0
|
|
mlane r5, r11, r3, r5 @ R5+=W7*ROWr16[5x8]=b2
|
|
mlane r7, r9, r3, r7 @ R7+=W3*ROWr16[5x8]=b3
|
|
rsbne r3, r3, #0 @ R3=-ROWr16[5x8]
|
|
ldrsh r4, [r14, #112] @ R4=COLr16[7x8]
|
|
mlane r1, r8, r3, r1 @ R7-=W1*ROWr16[5x8]=b1
|
|
@@ R3 is free now
|
|
teq r4, #0 @ if 0 then avoid muls
|
|
mlane r0, r11, r4, r0 @ R0+=W7*ROWr16[7x8]=b0
|
|
mlane r5, r9, r4, r5 @ R5+=W3*ROWr16[7x8]=b2
|
|
rsbne r4, r4, #0 @ R4=-ROWr16[7x8]
|
|
mlane r7, r8, r4, r7 @ R7-=W1*ROWr16[7x8]=b3
|
|
mlane r1, r10, r4, r1 @ R1-=W5*ROWr16[7x8]=b1
|
|
@@ R4 is free now
|
|
__end_b_evaluation2:
|
|
@@ at this point, R0=b0, R1=b1, R2 (free), R3 (free), R4 (free),
|
|
@@ R5=b2, R6 (free), R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
|
|
@@ R12=__const_ptr_, R14=&block[n]
|
|
|
|
__a_evaluation2:
|
|
@@ a0 = (W4 * col[8x0]) + (1 << (COL_SHIFT - 1));
|
|
@@ a1 = a0 + W6 * row[2];
|
|
@@ a2 = a0 - W6 * row[2];
|
|
@@ a3 = a0 - W2 * row[2];
|
|
@@ a0 = a0 + W2 * row[2];
|
|
ldrsh r6, [r14, #0]
|
|
ldr r9, [r12, #offW4] @ R9=W4
|
|
mul r6, r9, r6 @ R6=W4*ROWr16[0]
|
|
ldr r10, [r12, #offW6] @ R10=W6
|
|
ldrsh r4, [r14, #32] @ R4=ROWr16[2] (a3 not defined yet)
|
|
add r6, r6, #COL_SHIFTED_1 @ R6=W4*ROWr16[0] + 1<<(COL_SHIFT-1) (a0)
|
|
mul r11, r10, r4 @ R11=W6*ROWr16[2]
|
|
ldr r8, [r12, #offW2] @ R8=W2
|
|
add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
|
|
sub r3, r6, r11 @ R3=a0-W6*ROWr16[2] (a2)
|
|
mul r11, r8, r4 @ R11=W2*ROWr16[2]
|
|
sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
|
|
add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
|
|
|
|
@@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
|
|
@@ R5=b2, R6=a0, R7=b3, R8=W2, R9=W4, R10=W6, R11 (free),
|
|
@@ R12=__const_ptr_, R14=&block[n]
|
|
@@ a0 += W4*row[4]
|
|
@@ a1 -= W4*row[4]
|
|
@@ a2 -= W4*row[4]
|
|
@@ a3 += W4*row[4]
|
|
ldrsh r11, [r14, #64] @ R11=ROWr16[4]
|
|
teq r11, #0 @ if null avoid muls
|
|
mulne r11, r9, r11 @ R11=W4*ROWr16[4]
|
|
@@ R9 is free now
|
|
addne r6, r6, r11 @ R6+=W4*ROWr16[4] (a0)
|
|
subne r2, r2, r11 @ R2-=W4*ROWr16[4] (a1)
|
|
subne r3, r3, r11 @ R3-=W4*ROWr16[4] (a2)
|
|
ldrsh r9, [r14, #96] @ R9=ROWr16[6]
|
|
addne r4, r4, r11 @ R4+=W4*ROWr16[4] (a3)
|
|
@@ W6 alone is no more useful, save W2*ROWr16[6] in it instead
|
|
teq r9, #0 @ if null avoid muls
|
|
mulne r11, r10, r9 @ R11=W6*ROWr16[6]
|
|
addne r6, r6, r11 @ R6+=W6*ROWr16[6] (a0)
|
|
mulne r10, r8, r9 @ R10=W2*ROWr16[6]
|
|
@@ a0 += W6*row[6];
|
|
@@ a3 -= W6*row[6];
|
|
@@ a1 -= W2*row[6];
|
|
@@ a2 += W2*row[6];
|
|
subne r4, r4, r11 @ R4-=W6*ROWr16[6] (a3)
|
|
subne r2, r2, r10 @ R2-=W2*ROWr16[6] (a1)
|
|
addne r3, r3, r10 @ R3+=W2*ROWr16[6] (a2)
|
|
__end_a_evaluation2:
|
|
@@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
|
|
@@ R5=b2, R6=a0, R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
|
|
@@ R12=__const_ptr_, R14=&block[n]
|
|
@@ col[0 ] = ((a0 + b0) >> COL_SHIFT);
|
|
@@ col[8 ] = ((a1 + b1) >> COL_SHIFT);
|
|
@@ col[16] = ((a2 + b2) >> COL_SHIFT);
|
|
@@ col[24] = ((a3 + b3) >> COL_SHIFT);
|
|
@@ col[32] = ((a3 - b3) >> COL_SHIFT);
|
|
@@ col[40] = ((a2 - b2) >> COL_SHIFT);
|
|
@@ col[48] = ((a1 - b1) >> COL_SHIFT);
|
|
@@ col[56] = ((a0 - b0) >> COL_SHIFT);
|
|
@@@@@ no optimization here @@@@@
|
|
add r8, r6, r0 @ R8=a0+b0
|
|
add r9, r2, r1 @ R9=a1+b1
|
|
mov r8, r8, asr #COL_SHIFT
|
|
mov r9, r9, asr #COL_SHIFT
|
|
strh r8, [r14, #0]
|
|
strh r9, [r14, #16]
|
|
add r8, r3, r5 @ R8=a2+b2
|
|
add r9, r4, r7 @ R9=a3+b3
|
|
mov r8, r8, asr #COL_SHIFT
|
|
mov r9, r9, asr #COL_SHIFT
|
|
strh r8, [r14, #32]
|
|
strh r9, [r14, #48]
|
|
sub r8, r4, r7 @ R8=a3-b3
|
|
sub r9, r3, r5 @ R9=a2-b2
|
|
mov r8, r8, asr #COL_SHIFT
|
|
mov r9, r9, asr #COL_SHIFT
|
|
strh r8, [r14, #64]
|
|
strh r9, [r14, #80]
|
|
sub r8, r2, r1 @ R8=a1-b1
|
|
sub r9, r6, r0 @ R9=a0-b0
|
|
mov r8, r8, asr #COL_SHIFT
|
|
mov r9, r9, asr #COL_SHIFT
|
|
strh r8, [r14, #96]
|
|
strh r9, [r14, #112]
|
|
|
|
__end_col_loop:
|
|
@@ at this point, R0-R11 (free)
|
|
@@ R12=__const_ptr_, R14=&block[n]
|
|
ldr r0, [sp, #0] @ R0=block
|
|
teq r0, r14 @ compare current &block[n] to block, when block is reached, the loop is finished.
|
|
sub r14, r14, #2
|
|
bne __col_loop
|
|
|
|
|
|
|
|
|
|
__end_simple_idct_ARM:
|
|
@@ restore registers to previous status!
|
|
add sp, sp, #8 @@ the local variables!
|
|
ldmfd sp!, {r4-r11, r15} @@ update PC with LR content.
|
|
|
|
|
|
|
|
@@ kind of sub-function, here not to overload the common case.
|
|
__end_bef_a_evaluation:
|
|
add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
|
|
mul r11, r8, r4 @ R11=W2*ROWr16[2]
|
|
sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
|
|
add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
|
|
bal __end_a_evaluation
|
|
|
|
|
|
__constant_ptr__: @@ see #defines at the beginning of the source code for values.
|
|
.align
|
|
.word W1
|
|
.word W2
|
|
.word W3
|
|
.word W4
|
|
.word W5
|
|
.word W6
|
|
.word W7
|
|
.word MASK_MSHW
|