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/*
* idct BlackFin
*
* Copyright (C) 2007 Marc Hoffman <marc.hoffman@analog.com>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
This blackfin DSP code implements an 8x8 inverse type II DCT.
Prototype : void ff_bfin_idct(DCTELEM *in)
Registers Used : A0, A1, R0-R7, I0-I3, B0, B2, B3, M0-M2, L0-L3, P0-P5, LC0.
Performance :
Code Size : 498 Bytes.
Cycle Count : 417 Cycles
-----------------------------------------------------------
Libav conformance testing results
-----------------------------------------------------------
dct-test: modified with the following
dct_error("BFINidct", 1, ff_bfin_idct, idct, test);
produces the following output
libavcodec> ./dct-test -i
Libav DCT/IDCT test
8 15 -2 21 24 17 0 10
2 -10 -5 -5 -3 7 -14 -3
2 -13 -10 -19 18 -6 6 -2
9 4 16 -3 9 12 10 15
15 -9 -2 10 1 16 0 -15
-15 5 7 3 13 0 13 20
-6 -15 24 9 -18 1 9 -22
-8 25 23 2 -7 0 30 13
IDCT BFINidct: err_inf=1 err2=0.01002344 syserr=0.00150000 maxout=266 blockSumErr=64
IDCT BFINidct: 88.3 kdct/s
*/
#include "config.h"
#include "config_bfin.h"
#if defined(__FDPIC__) && CONFIG_SRAM
.section .l1.data.B,"aw",@progbits
#else
.data
#endif
.align 4;
coefs:
.short 0x5a82; // C4
.short 0x5a82; // C4
.short 0x30FC; //cos(3pi/8) C6
.short 0x7642; //cos(pi/8) C2
.short 0x18F9; //cos(7pi/16)
.short 0x7D8A; //cos(pi/16)
.short 0x471D; //cos(5pi/16)
.short 0x6A6E; //cos(3pi/16)
.short 0x18F9; //cos(7pi/16)
.short 0x7D8A; //cos(pi/16)
#if defined(__FDPIC__) && CONFIG_SRAM
.section .l1.data.A,"aw",@progbits
#endif
vtmp: .space 256
#define TMP0 FP-8
#define TMP1 FP-12
#define TMP2 FP-16
.text
DEFUN(idct,mL1,
(DCTELEM *block)):
/********************** Function Prologue *********************************/
link 16;
[--SP] = (R7:4, P5:3); // Push the registers onto the stack.
B0 = R0; // Pointer to Input matrix
RELOC(R1, P3, coefs); // Pointer to Coefficients
RELOC(R2, P3, vtmp); // Pointer to Temporary matrix
B3 = R1;
B2 = R2;
L3 = 20; // L3 is used for making the coefficient array
// circular.
// MUST BE RESTORED TO ZERO at function exit.
M1 = 16 (X); // All these registers are initialized for
M3 = 8(X); // modifying address offsets.
I0 = B0; // I0 points to Input Element (0, 0).
I2 = B0; // I2 points to Input Element (0, 0).
I2 += M3 || R0.H = W[I0];
// Element 0 is read into R0.H
I1 = I2; // I1 points to input Element (0, 6).
I1 += 4 || R0.L = W[I2++];
// I2 points to input Element (0, 4).
// Element 4 is read into R0.L.
P2 = 8 (X);
P3 = 32 (X);
P4 = -32 (X);
P5 = 98 (X);
R7 = 0x8000(Z);
I3 = B3; // I3 points to Coefficients
P0 = B2; // P0 points to array Element (0, 0) of temp
P1 = B2;
R7 = [I3++] || [TMP2]=R7; // Coefficient C4 is read into R7.H and R7.L.
MNOP;
NOP;
/*
* A1 = Y0 * cos(pi/4)
* A0 = Y0 * cos(pi/4)
* A1 = A1 + Y4 * cos(pi/4)
* A0 = A0 - Y4 * cos(pi/4)
* load:
* R1=(Y2,Y6)
* R7=(C2,C6)
* res:
* R3=Y0, R2=Y4
*/
A1=R7.H*R0.H, A0=R7.H*R0.H (IS) || I0+= 4 || R1.L=W[I1++];
R3=(A1+=R7.H*R0.L), R2=(A0-=R7.H*R0.L) (IS) || R1.H=W[I0--] || R7=[I3++];
LSETUP (.0, .1) LC0 = P2; // perform 8 1d idcts
P2 = 112 (X);
P1 = P1 + P2; // P1 points to element (7, 0) of temp buffer.
P2 = -94(X);
.0:
/*
* A1 = Y2 * cos(3pi/8)
* A0 = Y2 * cos(pi/8)
* A1 = A1 - Y6 * cos(pi/8)
* A0 = A0 + Y6 * cos(3pi/8)
* R5 = (Y1,Y7)
* R7 = (C1,C7)
* res:
* R1=Y2, R0=Y6
*/
A1=R7.L*R1.H, A0=R7.H*R1.H (IS) || I0+=4 || R5.H=W[I0];
R1=(A1-=R7.H*R1.L), R0=(A0+=R7.L*R1.L) (IS) || R5.L=W[I1--] || R7=[I3++];
/*
* Y0 = Y0 + Y6.
* Y4 = Y4 + Y2.
* Y2 = Y4 - Y2.
* Y6 = Y0 - Y6.
* R3 is saved
* R6.l=Y3
* note: R3: Y0, R2: Y4, R1: Y2, R0: Y6
*/
R3=R3+R0, R0=R3-R0;
R2=R2+R1, R1=R2-R1 || [TMP0]=R3 || R6.L=W[I0--];
/*
* Compute the odd portion (1,3,5,7) even is done.
*
* Y1 = C7 * Y1 - C1 * Y7 + C3 * Y5 - C5 * Y3.
* Y7 = C1 * Y1 + C7 * Y7 + C5 * Y5 + C3 * Y3.
* Y5 = C5 * Y1 + C3 * Y7 + C7 * Y5 - C1 * Y3.
* Y3 = C3 * Y1 - C5 * Y7 - C1 * Y5 - C7 * Y3.
*/
// R5=(Y1,Y7) R6=(Y5,Y3) // R7=(C1,C7)
A1 =R7.L*R5.H, A0 =R7.H*R5.H (IS) || [TMP1]=R2 || R6.H=W[I2--];
A1-=R7.H*R5.L, A0+=R7.L*R5.L (IS) || I0-=4 || R7=[I3++];
A1+=R7.H*R6.H, A0+=R7.L*R6.H (IS) || I0+=M1; // R7=(C3,C5)
R3 =(A1-=R7.L*R6.L), R2 =(A0+=R7.H*R6.L) (IS);
A1 =R7.L*R5.H, A0 =R7.H*R5.H (IS) || R4=[TMP0];
A1+=R7.H*R5.L, A0-=R7.L*R5.L (IS) || I1+=M1 || R7=[I3++]; // R7=(C1,C7)
A1+=R7.L*R6.H, A0-=R7.H*R6.H (IS);
R7 =(A1-=R7.H*R6.L), R6 =(A0-=R7.L*R6.L) (IS) || I2+=M1;
// R3=Y1, R2=Y7, R7=Y5, R6=Y3
/* Transpose write column. */
R5.H=R4+R2 (RND12); // Y0=Y0+Y7
R5.L=R4-R2 (RND12) || R4 = [TMP1]; // Y7=Y7-Y0
R2.H=R1+R7 (RND12) || W[P0++P3]=R5.H; // Y2=Y2+Y5 st Y0
R2.L=R1-R7 (RND12) || W[P1++P4]=R5.L || R7=[I3++]; // Y5=Y2-Y5 st Y7
R5.H=R0-R3 (RND12) || W[P0++P3]=R2.H || R1.L=W[I1++]; // Y1=Y6-Y1 st Y2
R5.L=R0+R3 (RND12) || W[P1++P4]=R2.L || R0.H=W[I0++]; // Y6=Y6+Y1 st Y5
R3.H=R4-R6 (RND12) || W[P0++P3]=R5.H || R0.L=W[I2++]; // Y3=Y3-Y4 st Y1
R3.L=R4+R6 (RND12) || W[P1++P4]=R5.L || R1.H=W[I0++]; // Y4=Y3+Y4 st Y6
/* pipeline loop start, + drain Y3, Y4 */
A1=R7.H*R0.H, A0=R7.H*R0.H (IS) || W[P0++P2]= R3.H || R1.H = W[I0--];
.1: R3=(A1+=R7.H*R0.L), R2=(A0-=R7.H*R0.L) (IS) || W[P1++P5]= R3.L || R7 = [I3++];
I0 = B2; // I0 points to Input Element (0, 0)
I2 = B2; // I2 points to Input Element (0, 0)
I2 += M3 || R0.H = W[I0];
// Y0 is read in R0.H
I1 = I2; // I1 points to input Element (0, 6)
I1 += 4 || R0.L = W[I2++];
// I2 points to input Element (0, 4)
// Y4 is read in R0.L
P2 = 8 (X);
I3 = B3; // I3 points to Coefficients
P0 = B0; // P0 points to array Element (0, 0) for writing
// output
P1 = B0;
R7 = [I3++]; // R7.H = C4 and R7.L = C4
NOP;
/*
* A1 = Y0 * cos(pi/4)
* A0 = Y0 * cos(pi/4)
* A1 = A1 + Y4 * cos(pi/4)
* A0 = A0 - Y4 * cos(pi/4)
* load:
* R1=(Y2,Y6)
* R7=(C2,C6)
* res:
* R3=Y0, R2=Y4
*/
A1=R7.H*R0.H, A0=R7.H*R0.H (IS) || I0+=4 || R1.L=W[I1++];
R3=(A1+=R7.H*R0.L), R2=(A0-=R7.H*R0.L) (IS) || R1.H=W[I0--] || R7=[I3++];
LSETUP (.2, .3) LC0 = P2; // peform 8 1d idcts
P2 = 112 (X);
P1 = P1 + P2;
P2 = -94(X);
.2:
/*
* A1 = Y2 * cos(3pi/8)
* A0 = Y2 * cos(pi/8)
* A1 = A1 - Y6 * cos(pi/8)
* A0 = A0 + Y6 * cos(3pi/8)
* R5 = (Y1,Y7)
* R7 = (C1,C7)
* res:
* R1=Y2, R0=Y6
*/
A1=R7.L*R1.H, A0=R7.H*R1.H (IS) || I0+=4 || R5.H=W[I0];
R1=(A1-=R7.H*R1.L), R0=(A0+=R7.L*R1.L) (IS) || R5.L=W[I1--] || R7=[I3++];
/*
* Y0 = Y0 + Y6.
* Y4 = Y4 + Y2.
* Y2 = Y4 - Y2.
* Y6 = Y0 - Y6.
* R3 is saved
* R6.l=Y3
* note: R3: Y0, R2: Y4, R1: Y2, R0: Y6
*/
R3=R3+R0, R0=R3-R0;
R2=R2+R1, R1=R2-R1 || [TMP0]=R3 || R6.L=W[I0--];
/*
* Compute the odd portion (1,3,5,7) even is done.
*
* Y1 = C7 * Y1 - C1 * Y7 + C3 * Y5 - C5 * Y3.
* Y7 = C1 * Y1 + C7 * Y7 + C5 * Y5 + C3 * Y3.
* Y5 = C5 * Y1 + C3 * Y7 + C7 * Y5 - C1 * Y3.
* Y3 = C3 * Y1 - C5 * Y7 - C1 * Y5 - C7 * Y3.
*/
// R5=(Y1,Y7) R6=(Y5,Y3) // R7=(C1,C7)
A1 =R7.L*R5.H, A0 =R7.H*R5.H (IS) || [TMP1]=R2 || R6.H=W[I2--];
A1-=R7.H*R5.L, A0+=R7.L*R5.L (IS) || I0-=4 || R7=[I3++];
A1+=R7.H*R6.H, A0+=R7.L*R6.H (IS) || I0+=M1; // R7=(C3,C5)
R3 =(A1-=R7.L*R6.L), R2 =(A0+=R7.H*R6.L) (IS);
A1 =R7.L*R5.H, A0 =R7.H*R5.H (IS) || R4=[TMP0];
A1+=R7.H*R5.L, A0-=R7.L*R5.L (IS) || I1+=M1 || R7=[I3++]; // R7=(C1,C7)
A1+=R7.L*R6.H, A0-=R7.H*R6.H (IS);
R7 =(A1-=R7.H*R6.L), R6 =(A0-=R7.L*R6.L) (IS) || I2+=M1;
// R3=Y1, R2=Y7, R7=Y5, R6=Y3
/* Transpose write column. */
R5.H=R4+R2 (RND20); // Y0=Y0+Y7
R5.L=R4-R2 (RND20) || R4 = [TMP1]; // Y7=Y7-Y0
R2.H=R1+R7 (RND20) || W[P0++P3]=R5.H; // Y2=Y2+Y5 st Y0
R2.L=R1-R7 (RND20) || W[P1++P4]=R5.L || R7=[I3++]; // Y5=Y2-Y5 st Y7
R5.H=R0-R3 (RND20) || W[P0++P3]=R2.H || R1.L=W[I1++]; // Y1=Y6-Y1 st Y2
R5.L=R0+R3 (RND20) || W[P1++P4]=R2.L || R0.H=W[I0++]; // Y6=Y6+Y1 st Y5
R3.H=R4-R6 (RND20) || W[P0++P3]=R5.H || R0.L=W[I2++]; // Y3=Y3-Y4 st Y1
R3.L=R4+R6 (RND20) || W[P1++P4]=R5.L || R1.H=W[I0++]; // Y4=Y3+Y4 st Y6
/* pipeline loop start, + drain Y3, Y4 */
A1=R7.H*R0.H, A0=R7.H*R0.H (IS) || W[P0++P2]= R3.H || R1.H = W[I0--];
.3: R3=(A1+=R7.H*R0.L), R2=(A0-=R7.H*R0.L) (IS) || W[P1++P5]= R3.L || R7 = [I3++];
L3 = 0;
(R7:4,P5:3)=[SP++];
unlink;
RTS;
DEFUN_END(idct)
|
