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