| 1 | /*
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| 2 | * simple_idct_arm.S
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| 3 | * Copyright (C) 2002 Frederic 'dilb' Boulay.
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| 4 | * All Rights Reserved.
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| 5 | *
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| 6 | * Author: Frederic Boulay <[email protected]>
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| 7 | *
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| 8 | * You can redistribute this file and/or modify
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| 9 | * it under the terms of the GNU General Public License (version 2)
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| 10 | * as published by the Free Software Foundation.
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| 11 | *
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| 12 | * This file is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with this library; if not, write to the Free Software
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 20 | *
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| 21 | *
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| 22 | * The function defined in this file, is derived from the simple_idct function
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| 23 | * from the libavcodec library part of the ffmpeg project.
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| 24 | */
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| 25 |
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| 26 | /* useful constants for the algorithm, they are save in __constant_ptr__ at */
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| 27 | /* the end of the source code.*/
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| 28 | #define W1 22725
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| 29 | #define W2 21407
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| 30 | #define W3 19266
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| 31 | #define W4 16383
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| 32 | #define W5 12873
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| 33 | #define W6 8867
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| 34 | #define W7 4520
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| 35 | #define MASK_MSHW 0xFFFF0000
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| 36 |
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| 37 | /* offsets of the constants in the vector */
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| 38 | #define offW1 0
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| 39 | #define offW2 4
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| 40 | #define offW3 8
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| 41 | #define offW4 12
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| 42 | #define offW5 16
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| 43 | #define offW6 20
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| 44 | #define offW7 24
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| 45 | #define offMASK_MSHW 28
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| 46 |
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| 47 | #define ROW_SHIFT 11
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| 48 | #define ROW_SHIFT2MSHW (16-11)
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| 49 | #define COL_SHIFT 20
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| 50 | #define ROW_SHIFTED_1 1024 /* 1<< (ROW_SHIFT-1) */
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| 51 | #define COL_SHIFTED_1 524288 /* 1<< (COL_SHIFT-1) */
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| 52 |
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| 53 |
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| 54 | .text
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| 55 | .align
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| 56 | .global simple_idct_ARM
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| 57 |
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| 58 | simple_idct_ARM:
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| 59 | @@ void simple_idct_ARM(int16_t *block)
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| 60 | @@ save stack for reg needed (take all of them),
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| 61 | @@ R0-R3 are scratch regs, so no need to save them, but R0 contains the pointer to block
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| 62 | @@ so it must not be overwritten, if it is not saved!!
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| 63 | @@ R12 is another scratch register, so it should not be saved too
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| 64 | @@ save all registers
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| 65 | stmfd sp!, {r4-r11, r14} @ R14 is also called LR
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| 66 | @@ at this point, R0=block, other registers are free.
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| 67 | 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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| 68 | 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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| 69 | @@ add 2 temporary variables in the stack: R0 and R14
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| 70 | sub sp, sp, #8 @ allow 2 local variables
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| 71 | str r0, [sp, #0] @ save block in sp[0]
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| 72 | @@ stack status
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| 73 | @@ sp+4 free
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| 74 | @@ sp+0 R0 (block)
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| 75 |
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| 76 |
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| 77 | @@ at this point, R0=block, R14=&block[56], R12=__const_ptr_, R1-R11 free
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| 78 |
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| 79 |
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| 80 | __row_loop:
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| 81 | @@ read the row and check if it is null, almost null, or not, according to strongarm specs, it is not necessary to optimise ldr accesses (i.e. split 32bits in 2 16bits words), at least it gives more usable registers :)
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| 82 | ldr r1, [r14, #0] @ R1=(int32)(R12)[0]=ROWr32[0] (relative row cast to a 32b pointer)
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| 83 | ldr r2, [r14, #4] @ R2=(int32)(R12)[1]=ROWr32[1]
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| 84 | ldr r3, [r14, #8] @ R3=ROWr32[2]
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| 85 | ldr r4, [r14, #12] @ R4=ROWr32[3]
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| 86 | @@ 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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| 87 | @@ if ROWr16[0] is the only one not null, then proceed with this special case (branch __almost_empty_row)
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| 88 | @@ else follow the complete algorithm.
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| 89 | @@ at this point, R0=block, R14=&block[n], R12=__const_ptr_, R1=ROWr32[0], R2=ROWr32[1],
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| 90 | @@ R3=ROWr32[2], R4=ROWr32[3], R5-R11 free
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| 91 | orr r5, r4, r3 @ R5=R4 | R3
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| 92 | orr r5, r5, r2 @ R5=R4 | R3 | R2
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| 93 | orrs r6, r5, r1 @ Test R5 | R1 (the aim is to check if everything is null)
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| 94 | beq __end_row_loop
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| 95 | mov r7, r1, asr #16 @ R7=R1>>16=ROWr16[1] (evaluate it now, as it could be useful later)
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| 96 | ldrsh r6, [r14, #0] @ R6=ROWr16[0]
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| 97 | orrs r5, r5, r7 @ R5=R4 | R3 | R2 | R7
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| 98 | beq __almost_empty_row
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| 99 |
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| 100 | __b_evaluation:
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| 101 | @@ at this point, R0=block (temp), R1(free), R2=ROWr32[1], R3=ROWr32[2], R4=ROWr32[3],
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| 102 | @@ R5=(temp), R6=ROWr16[0], R7=ROWr16[1], R8-R11 free,
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| 103 | @@ R12=__const_ptr_, R14=&block[n]
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| 104 | @@ to save some registers/calls, proceed with b0-b3 first, followed by a0-a3
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| 105 |
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| 106 | @@ MUL16(b0, W1, row[1]);
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| 107 | @@ MUL16(b1, W3, row[1]);
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| 108 | @@ MUL16(b2, W5, row[1]);
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| 109 | @@ MUL16(b3, W7, row[1]);
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| 110 | @@ MAC16(b0, W3, row[3]);
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| 111 | @@ MAC16(b1, -W7, row[3]);
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| 112 | @@ MAC16(b2, -W1, row[3]);
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| 113 | @@ MAC16(b3, -W5, row[3]);
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| 114 | ldr r8, [r12, #offW1] @ R8=W1
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| 115 | mov r2, r2, asr #16 @ R2=ROWr16[3]
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| 116 | 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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| 117 | ldr r9, [r12, #offW3] @ R9=W3
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| 118 | ldr r10, [r12, #offW5] @ R10=W5
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| 119 | 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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| 120 | ldr r11, [r12, #offW7] @ R11=W7
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| 121 | 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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| 122 | 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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| 123 | teq r2, #0 @ if null avoid muls
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| 124 | 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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| 125 | rsbne r2, r2, #0 @ R2=-ROWr16[3]
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| 126 | 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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| 127 | 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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| 128 | 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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| 129 |
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| 130 | @@ at this point, R0=b0, R1=b1, R2 (free), R3=ROWr32[2], R4=ROWr32[3],
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| 131 | @@ R5=b2, R6=ROWr16[0], R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
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| 132 | @@ R12=__const_ptr_, R14=&block[n]
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| 133 | @@ temp = ((uint32_t*)row)[2] | ((uint32_t*)row)[3];
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| 134 | @@ if (temp != 0) {}
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| 135 | orrs r2, r3, r4 @ R2=ROWr32[2] | ROWr32[3]
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| 136 | beq __end_b_evaluation
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| 137 |
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| 138 | @@ at this point, R0=b0, R1=b1, R2 (free), R3=ROWr32[2], R4=ROWr32[3],
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| 139 | @@ R5=b2, R6=ROWr16[0], R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
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| 140 | @@ R12=__const_ptr_, R14=&block[n]
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| 141 | @@ MAC16(b0, W5, row[5]);
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| 142 | @@ MAC16(b2, W7, row[5]);
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| 143 | @@ MAC16(b3, W3, row[5]);
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| 144 | @@ MAC16(b1, -W1, row[5]);
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| 145 | @@ MAC16(b0, W7, row[7]);
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| 146 | @@ MAC16(b2, W3, row[7]);
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| 147 | @@ MAC16(b3, -W1, row[7]);
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| 148 | @@ MAC16(b1, -W5, row[7]);
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| 149 | mov r3, r3, asr #16 @ R3=ROWr16[5]
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| 150 | teq r3, #0 @ if null avoid muls
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| 151 | mlane r0, r10, r3, r0 @ R0+=W5*ROWr16[5]=b0
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| 152 | mov r4, r4, asr #16 @ R4=ROWr16[7]
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| 153 | mlane r5, r11, r3, r5 @ R5+=W7*ROWr16[5]=b2
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| 154 | mlane r7, r9, r3, r7 @ R7+=W3*ROWr16[5]=b3
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| 155 | rsbne r3, r3, #0 @ R3=-ROWr16[5]
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| 156 | mlane r1, r8, r3, r1 @ R7-=W1*ROWr16[5]=b1
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| 157 | @@ R3 is free now
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| 158 | teq r4, #0 @ if null avoid muls
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| 159 | mlane r0, r11, r4, r0 @ R0+=W7*ROWr16[7]=b0
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| 160 | mlane r5, r9, r4, r5 @ R5+=W3*ROWr16[7]=b2
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| 161 | rsbne r4, r4, #0 @ R4=-ROWr16[7]
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| 162 | mlane r7, r8, r4, r7 @ R7-=W1*ROWr16[7]=b3
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| 163 | mlane r1, r10, r4, r1 @ R1-=W5*ROWr16[7]=b1
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| 164 | @@ R4 is free now
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| 165 | __end_b_evaluation:
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| 166 | @@ at this point, R0=b0, R1=b1, R2=ROWr32[2] | ROWr32[3] (tmp), R3 (free), R4 (free),
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| 167 | @@ R5=b2, R6=ROWr16[0], R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
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| 168 | @@ R12=__const_ptr_, R14=&block[n]
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| 169 |
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| 170 | __a_evaluation:
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| 171 | @@ a0 = (W4 * row[0]) + (1 << (ROW_SHIFT - 1));
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| 172 | @@ a1 = a0 + W6 * row[2];
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| 173 | @@ a2 = a0 - W6 * row[2];
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| 174 | @@ a3 = a0 - W2 * row[2];
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| 175 | @@ a0 = a0 + W2 * row[2];
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| 176 | ldr r9, [r12, #offW4] @ R9=W4
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| 177 | mul r6, r9, r6 @ R6=W4*ROWr16[0]
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| 178 | ldr r10, [r12, #offW6] @ R10=W6
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| 179 | ldrsh r4, [r14, #4] @ R4=ROWr16[2] (a3 not defined yet)
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| 180 | add r6, r6, #ROW_SHIFTED_1 @ R6=W4*ROWr16[0] + 1<<(ROW_SHIFT-1) (a0)
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| 181 |
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| 182 | mul r11, r10, r4 @ R11=W6*ROWr16[2]
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| 183 | ldr r8, [r12, #offW2] @ R8=W2
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| 184 | sub r3, r6, r11 @ R3=a0-W6*ROWr16[2] (a2)
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| 185 | @@ temp = ((uint32_t*)row)[2] | ((uint32_t*)row)[3];
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| 186 | @@ if (temp != 0) {}
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| 187 | teq r2, #0
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| 188 | beq __end_bef_a_evaluation
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| 189 |
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| 190 | add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
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| 191 | mul r11, r8, r4 @ R11=W2*ROWr16[2]
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| 192 | sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
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| 193 | add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
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| 194 |
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| 195 |
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| 196 | @@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
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| 197 | @@ R5=b2, R6=a0, R7=b3, R8=W2, R9=W4, R10=W6, R11 (free),
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| 198 | @@ R12=__const_ptr_, R14=&block[n]
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| 199 |
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| 200 |
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| 201 | @@ a0 += W4*row[4]
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| 202 | @@ a1 -= W4*row[4]
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| 203 | @@ a2 -= W4*row[4]
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| 204 | @@ a3 += W4*row[4]
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| 205 | ldrsh r11, [r14, #8] @ R11=ROWr16[4]
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| 206 | teq r11, #0 @ if null avoid muls
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| 207 | mulne r11, r9, r11 @ R11=W4*ROWr16[4]
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| 208 | @@ R9 is free now
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| 209 | ldrsh r9, [r14, #12] @ R9=ROWr16[6]
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| 210 | addne r6, r6, r11 @ R6+=W4*ROWr16[4] (a0)
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| 211 | subne r2, r2, r11 @ R2-=W4*ROWr16[4] (a1)
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| 212 | subne r3, r3, r11 @ R3-=W4*ROWr16[4] (a2)
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| 213 | addne r4, r4, r11 @ R4+=W4*ROWr16[4] (a3)
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| 214 | @@ W6 alone is no more useful, save W2*ROWr16[6] in it instead
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| 215 | teq r9, #0 @ if null avoid muls
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| 216 | mulne r11, r10, r9 @ R11=W6*ROWr16[6]
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| 217 | addne r6, r6, r11 @ R6+=W6*ROWr16[6] (a0)
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| 218 | mulne r10, r8, r9 @ R10=W2*ROWr16[6]
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| 219 | @@ a0 += W6*row[6];
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| 220 | @@ a3 -= W6*row[6];
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| 221 | @@ a1 -= W2*row[6];
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| 222 | @@ a2 += W2*row[6];
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| 223 | subne r4, r4, r11 @ R4-=W6*ROWr16[6] (a3)
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| 224 | subne r2, r2, r10 @ R2-=W2*ROWr16[6] (a1)
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| 225 | addne r3, r3, r10 @ R3+=W2*ROWr16[6] (a2)
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| 226 |
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| 227 | __end_a_evaluation:
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| 228 | @@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
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| 229 | @@ R5=b2, R6=a0, R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
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| 230 | @@ R12=__const_ptr_, R14=&block[n]
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| 231 | @@ row[0] = (a0 + b0) >> ROW_SHIFT;
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| 232 | @@ row[1] = (a1 + b1) >> ROW_SHIFT;
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| 233 | @@ row[2] = (a2 + b2) >> ROW_SHIFT;
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| 234 | @@ row[3] = (a3 + b3) >> ROW_SHIFT;
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| 235 | @@ row[4] = (a3 - b3) >> ROW_SHIFT;
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| 236 | @@ row[5] = (a2 - b2) >> ROW_SHIFT;
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| 237 | @@ row[6] = (a1 - b1) >> ROW_SHIFT;
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| 238 | @@ row[7] = (a0 - b0) >> ROW_SHIFT;
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| 239 | add r8, r6, r0 @ R8=a0+b0
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| 240 | add r9, r2, r1 @ R9=a1+b1
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| 241 | @@ put 2 16 bits half-words in a 32bits word
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| 242 | @@ ROWr32[0]=ROWr16[0] | (ROWr16[1]<<16) (only Little Endian compliant then!!!)
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| 243 | ldr r10, [r12, #offMASK_MSHW] @ R10=0xFFFF0000
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| 244 | and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a1+b1)<<5)
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| 245 | mvn r11, r10 @ R11= NOT R10= 0x0000FFFF
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| 246 | and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a0+b0)>>11)
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| 247 | orr r8, r8, r9
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| 248 | str r8, [r14, #0]
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| 249 |
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| 250 | add r8, r3, r5 @ R8=a2+b2
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| 251 | add r9, r4, r7 @ R9=a3+b3
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| 252 | and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a3+b3)<<5)
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| 253 | and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a2+b2)>>11)
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| 254 | orr r8, r8, r9
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| 255 | str r8, [r14, #4]
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| 256 |
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| 257 | sub r8, r4, r7 @ R8=a3-b3
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| 258 | sub r9, r3, r5 @ R9=a2-b2
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| 259 | and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a2-b2)<<5)
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| 260 | and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a3-b3)>>11)
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| 261 | orr r8, r8, r9
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| 262 | str r8, [r14, #8]
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| 263 |
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| 264 | sub r8, r2, r1 @ R8=a1-b1
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| 265 | sub r9, r6, r0 @ R9=a0-b0
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| 266 | and r9, r10, r9, lsl #ROW_SHIFT2MSHW @ R9=0xFFFF0000 & ((a0-b0)<<5)
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| 267 | and r8, r11, r8, asr #ROW_SHIFT @ R8=0x0000FFFF & ((a1-b1)>>11)
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| 268 | orr r8, r8, r9
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| 269 | str r8, [r14, #12]
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| 270 |
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| 271 | bal __end_row_loop
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| 272 |
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| 273 | __almost_empty_row:
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| 274 | @@ the row was empty, except ROWr16[0], now, management of this special case
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| 275 | @@ at this point, R0=block, R14=&block[n], R12=__const_ptr_, R1=ROWr32[0], R2=ROWr32[1],
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| 276 | @@ R3=ROWr32[2], R4=ROWr32[3], R5=(temp), R6=ROWr16[0], R7=ROWr16[1],
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| 277 | @@ R8=0xFFFF (temp), R9-R11 free
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| 278 | mov r8, #0x10000 @ R8=0xFFFF (2 steps needed!) it saves a ldr call (because of delay run).
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| 279 | sub r8, r8, #1 @ R8 is now ready.
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| 280 | and r5, r8, r6, lsl #3 @ R5=R8 & (R6<<3)= (ROWr16[0]<<3) & 0xFFFF
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| 281 | orr r5, r5, r5, lsl #16 @ R5=R5 | (R5<<16)
|
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| 282 | str r5, [r14, #0] @ R14[0]=ROWr32[0]=R5
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| 283 | str r5, [r14, #4] @ R14[4]=ROWr32[1]=R5
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| 284 | str r5, [r14, #8] @ R14[8]=ROWr32[2]=R5
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| 285 | str r5, [r14, #12] @ R14[12]=ROWr32[3]=R5
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| 286 |
|
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| 287 | __end_row_loop:
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| 288 | @@ at this point, R0-R11 (free)
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| 289 | @@ R12=__const_ptr_, R14=&block[n]
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| 290 | ldr r0, [sp, #0] @ R0=block
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| 291 | teq r0, r14 @ compare current &block[8*n] to block, when block is reached, the loop is finished.
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| 292 | sub r14, r14, #16
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| 293 | bne __row_loop
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| 294 |
|
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| 295 |
|
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| 296 |
|
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| 297 | @@ at this point, R0=block, R1-R11 (free)
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| 298 | @@ R12=__const_ptr_, R14=&block[n]
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| 299 | 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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| 300 | __col_loop:
|
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| 301 |
|
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| 302 | __b_evaluation2:
|
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| 303 | @@ at this point, R0=block (temp), R1-R11 (free)
|
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| 304 | @@ R12=__const_ptr_, R14=&block[n]
|
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| 305 | @@ proceed with b0-b3 first, followed by a0-a3
|
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| 306 | @@ MUL16(b0, W1, col[8x1]);
|
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| 307 | @@ MUL16(b1, W3, col[8x1]);
|
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| 308 | @@ MUL16(b2, W5, col[8x1]);
|
|---|
| 309 | @@ MUL16(b3, W7, col[8x1]);
|
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| 310 | @@ MAC16(b0, W3, col[8x3]);
|
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| 311 | @@ MAC16(b1, -W7, col[8x3]);
|
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| 312 | @@ MAC16(b2, -W1, col[8x3]);
|
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| 313 | @@ MAC16(b3, -W5, col[8x3]);
|
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| 314 | ldr r8, [r12, #offW1] @ R8=W1
|
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| 315 | ldrsh r7, [r14, #16]
|
|---|
| 316 | mul r0, r8, r7 @ R0=W1*ROWr16[1]=b0 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|---|
| 317 | ldr r9, [r12, #offW3] @ R9=W3
|
|---|
| 318 | ldr r10, [r12, #offW5] @ R10=W5
|
|---|
| 319 | mul r1, r9, r7 @ R1=W3*ROWr16[1]=b1 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|---|
| 320 | ldr r11, [r12, #offW7] @ R11=W7
|
|---|
| 321 | mul r5, r10, r7 @ R5=W5*ROWr16[1]=b2 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|---|
| 322 | ldrsh r2, [r14, #48]
|
|---|
| 323 | mul r7, r11, r7 @ R7=W7*ROWr16[1]=b3 (ROWr16[1] must be the second arg, to have the possibility to save 1 cycle)
|
|---|
| 324 | teq r2, #0 @ if 0, then avoid muls
|
|---|
| 325 | 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)
|
|---|
| 326 | rsbne r2, r2, #0 @ R2=-ROWr16[3]
|
|---|
| 327 | 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)
|
|---|
| 328 | 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)
|
|---|
| 329 | 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)
|
|---|
| 330 |
|
|---|
| 331 | @@ at this point, R0=b0, R1=b1, R2 (free), R3 (free), R4 (free),
|
|---|
| 332 | @@ R5=b2, R6 (free), R7=b3, R8=W1, R9=W3, R10=W5, R11=W7,
|
|---|
| 333 | @@ R12=__const_ptr_, R14=&block[n]
|
|---|
| 334 | @@ MAC16(b0, W5, col[5x8]);
|
|---|
| 335 | @@ MAC16(b2, W7, col[5x8]);
|
|---|
| 336 | @@ MAC16(b3, W3, col[5x8]);
|
|---|
| 337 | @@ MAC16(b1, -W1, col[5x8]);
|
|---|
| 338 | @@ MAC16(b0, W7, col[7x8]);
|
|---|
| 339 | @@ MAC16(b2, W3, col[7x8]);
|
|---|
| 340 | @@ MAC16(b3, -W1, col[7x8]);
|
|---|
| 341 | @@ MAC16(b1, -W5, col[7x8]);
|
|---|
| 342 | ldrsh r3, [r14, #80] @ R3=COLr16[5x8]
|
|---|
| 343 | teq r3, #0 @ if 0 then avoid muls
|
|---|
| 344 | mlane r0, r10, r3, r0 @ R0+=W5*ROWr16[5x8]=b0
|
|---|
| 345 | mlane r5, r11, r3, r5 @ R5+=W7*ROWr16[5x8]=b2
|
|---|
| 346 | mlane r7, r9, r3, r7 @ R7+=W3*ROWr16[5x8]=b3
|
|---|
| 347 | rsbne r3, r3, #0 @ R3=-ROWr16[5x8]
|
|---|
| 348 | ldrsh r4, [r14, #112] @ R4=COLr16[7x8]
|
|---|
| 349 | mlane r1, r8, r3, r1 @ R7-=W1*ROWr16[5x8]=b1
|
|---|
| 350 | @@ R3 is free now
|
|---|
| 351 | teq r4, #0 @ if 0 then avoid muls
|
|---|
| 352 | mlane r0, r11, r4, r0 @ R0+=W7*ROWr16[7x8]=b0
|
|---|
| 353 | mlane r5, r9, r4, r5 @ R5+=W3*ROWr16[7x8]=b2
|
|---|
| 354 | rsbne r4, r4, #0 @ R4=-ROWr16[7x8]
|
|---|
| 355 | mlane r7, r8, r4, r7 @ R7-=W1*ROWr16[7x8]=b3
|
|---|
| 356 | mlane r1, r10, r4, r1 @ R1-=W5*ROWr16[7x8]=b1
|
|---|
| 357 | @@ R4 is free now
|
|---|
| 358 | __end_b_evaluation2:
|
|---|
| 359 | @@ at this point, R0=b0, R1=b1, R2 (free), R3 (free), R4 (free),
|
|---|
| 360 | @@ R5=b2, R6 (free), R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
|
|---|
| 361 | @@ R12=__const_ptr_, R14=&block[n]
|
|---|
| 362 |
|
|---|
| 363 | __a_evaluation2:
|
|---|
| 364 | @@ a0 = (W4 * col[8x0]) + (1 << (COL_SHIFT - 1));
|
|---|
| 365 | @@ a1 = a0 + W6 * row[2];
|
|---|
| 366 | @@ a2 = a0 - W6 * row[2];
|
|---|
| 367 | @@ a3 = a0 - W2 * row[2];
|
|---|
| 368 | @@ a0 = a0 + W2 * row[2];
|
|---|
| 369 | ldrsh r6, [r14, #0]
|
|---|
| 370 | ldr r9, [r12, #offW4] @ R9=W4
|
|---|
| 371 | mul r6, r9, r6 @ R6=W4*ROWr16[0]
|
|---|
| 372 | ldr r10, [r12, #offW6] @ R10=W6
|
|---|
| 373 | ldrsh r4, [r14, #32] @ R4=ROWr16[2] (a3 not defined yet)
|
|---|
| 374 | add r6, r6, #COL_SHIFTED_1 @ R6=W4*ROWr16[0] + 1<<(COL_SHIFT-1) (a0)
|
|---|
| 375 | mul r11, r10, r4 @ R11=W6*ROWr16[2]
|
|---|
| 376 | ldr r8, [r12, #offW2] @ R8=W2
|
|---|
| 377 | add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
|
|---|
| 378 | sub r3, r6, r11 @ R3=a0-W6*ROWr16[2] (a2)
|
|---|
| 379 | mul r11, r8, r4 @ R11=W2*ROWr16[2]
|
|---|
| 380 | sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
|
|---|
| 381 | add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
|
|---|
| 382 |
|
|---|
| 383 | @@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
|
|---|
| 384 | @@ R5=b2, R6=a0, R7=b3, R8=W2, R9=W4, R10=W6, R11 (free),
|
|---|
| 385 | @@ R12=__const_ptr_, R14=&block[n]
|
|---|
| 386 | @@ a0 += W4*row[4]
|
|---|
| 387 | @@ a1 -= W4*row[4]
|
|---|
| 388 | @@ a2 -= W4*row[4]
|
|---|
| 389 | @@ a3 += W4*row[4]
|
|---|
| 390 | ldrsh r11, [r14, #64] @ R11=ROWr16[4]
|
|---|
| 391 | teq r11, #0 @ if null avoid muls
|
|---|
| 392 | mulne r11, r9, r11 @ R11=W4*ROWr16[4]
|
|---|
| 393 | @@ R9 is free now
|
|---|
| 394 | addne r6, r6, r11 @ R6+=W4*ROWr16[4] (a0)
|
|---|
| 395 | subne r2, r2, r11 @ R2-=W4*ROWr16[4] (a1)
|
|---|
| 396 | subne r3, r3, r11 @ R3-=W4*ROWr16[4] (a2)
|
|---|
| 397 | ldrsh r9, [r14, #96] @ R9=ROWr16[6]
|
|---|
| 398 | addne r4, r4, r11 @ R4+=W4*ROWr16[4] (a3)
|
|---|
| 399 | @@ W6 alone is no more useful, save W2*ROWr16[6] in it instead
|
|---|
| 400 | teq r9, #0 @ if null avoid muls
|
|---|
| 401 | mulne r11, r10, r9 @ R11=W6*ROWr16[6]
|
|---|
| 402 | addne r6, r6, r11 @ R6+=W6*ROWr16[6] (a0)
|
|---|
| 403 | mulne r10, r8, r9 @ R10=W2*ROWr16[6]
|
|---|
| 404 | @@ a0 += W6*row[6];
|
|---|
| 405 | @@ a3 -= W6*row[6];
|
|---|
| 406 | @@ a1 -= W2*row[6];
|
|---|
| 407 | @@ a2 += W2*row[6];
|
|---|
| 408 | subne r4, r4, r11 @ R4-=W6*ROWr16[6] (a3)
|
|---|
| 409 | subne r2, r2, r10 @ R2-=W2*ROWr16[6] (a1)
|
|---|
| 410 | addne r3, r3, r10 @ R3+=W2*ROWr16[6] (a2)
|
|---|
| 411 | __end_a_evaluation2:
|
|---|
| 412 | @@ at this point, R0=b0, R1=b1, R2=a1, R3=a2, R4=a3,
|
|---|
| 413 | @@ R5=b2, R6=a0, R7=b3, R8 (free), R9 (free), R10 (free), R11 (free),
|
|---|
| 414 | @@ R12=__const_ptr_, R14=&block[n]
|
|---|
| 415 | @@ col[0 ] = ((a0 + b0) >> COL_SHIFT);
|
|---|
| 416 | @@ col[8 ] = ((a1 + b1) >> COL_SHIFT);
|
|---|
| 417 | @@ col[16] = ((a2 + b2) >> COL_SHIFT);
|
|---|
| 418 | @@ col[24] = ((a3 + b3) >> COL_SHIFT);
|
|---|
| 419 | @@ col[32] = ((a3 - b3) >> COL_SHIFT);
|
|---|
| 420 | @@ col[40] = ((a2 - b2) >> COL_SHIFT);
|
|---|
| 421 | @@ col[48] = ((a1 - b1) >> COL_SHIFT);
|
|---|
| 422 | @@ col[56] = ((a0 - b0) >> COL_SHIFT);
|
|---|
| 423 | @@@@@ no optimisation here @@@@@
|
|---|
| 424 | add r8, r6, r0 @ R8=a0+b0
|
|---|
| 425 | add r9, r2, r1 @ R9=a1+b1
|
|---|
| 426 | mov r8, r8, asr #COL_SHIFT
|
|---|
| 427 | mov r9, r9, asr #COL_SHIFT
|
|---|
| 428 | strh r8, [r14, #0]
|
|---|
| 429 | strh r9, [r14, #16]
|
|---|
| 430 | add r8, r3, r5 @ R8=a2+b2
|
|---|
| 431 | add r9, r4, r7 @ R9=a3+b3
|
|---|
| 432 | mov r8, r8, asr #COL_SHIFT
|
|---|
| 433 | mov r9, r9, asr #COL_SHIFT
|
|---|
| 434 | strh r8, [r14, #32]
|
|---|
| 435 | strh r9, [r14, #48]
|
|---|
| 436 | sub r8, r4, r7 @ R8=a3-b3
|
|---|
| 437 | sub r9, r3, r5 @ R9=a2-b2
|
|---|
| 438 | mov r8, r8, asr #COL_SHIFT
|
|---|
| 439 | mov r9, r9, asr #COL_SHIFT
|
|---|
| 440 | strh r8, [r14, #64]
|
|---|
| 441 | strh r9, [r14, #80]
|
|---|
| 442 | sub r8, r2, r1 @ R8=a1-b1
|
|---|
| 443 | sub r9, r6, r0 @ R9=a0-b0
|
|---|
| 444 | mov r8, r8, asr #COL_SHIFT
|
|---|
| 445 | mov r9, r9, asr #COL_SHIFT
|
|---|
| 446 | strh r8, [r14, #96]
|
|---|
| 447 | strh r9, [r14, #112]
|
|---|
| 448 |
|
|---|
| 449 | __end_col_loop:
|
|---|
| 450 | @@ at this point, R0-R11 (free)
|
|---|
| 451 | @@ R12=__const_ptr_, R14=&block[n]
|
|---|
| 452 | ldr r0, [sp, #0] @ R0=block
|
|---|
| 453 | teq r0, r14 @ compare current &block[n] to block, when block is reached, the loop is finished.
|
|---|
| 454 | sub r14, r14, #2
|
|---|
| 455 | bne __col_loop
|
|---|
| 456 |
|
|---|
| 457 |
|
|---|
| 458 |
|
|---|
| 459 |
|
|---|
| 460 | __end_simple_idct_ARM:
|
|---|
| 461 | @@ restore registers to previous status!
|
|---|
| 462 | add sp, sp, #8 @@ the local variables!
|
|---|
| 463 | ldmfd sp!, {r4-r11, r15} @@ update PC with LR content.
|
|---|
| 464 |
|
|---|
| 465 |
|
|---|
| 466 |
|
|---|
| 467 | @@ kind of sub-function, here not to overload the common case.
|
|---|
| 468 | __end_bef_a_evaluation:
|
|---|
| 469 | add r2, r6, r11 @ R2=a0+W6*ROWr16[2] (a1)
|
|---|
| 470 | mul r11, r8, r4 @ R11=W2*ROWr16[2]
|
|---|
| 471 | sub r4, r6, r11 @ R4=a0-W2*ROWr16[2] (a3)
|
|---|
| 472 | add r6, r6, r11 @ R6=a0+W2*ROWr16[2] (a0)
|
|---|
| 473 | bal __end_a_evaluation
|
|---|
| 474 |
|
|---|
| 475 |
|
|---|
| 476 | __constant_ptr__: @@ see #defines at the beginning of the source code for values.
|
|---|
| 477 | .align
|
|---|
| 478 | .word W1
|
|---|
| 479 | .word W2
|
|---|
| 480 | .word W3
|
|---|
| 481 | .word W4
|
|---|
| 482 | .word W5
|
|---|
| 483 | .word W6
|
|---|
| 484 | .word W7
|
|---|
| 485 | .word MASK_MSHW
|
|---|
