| /* |
| * fdct BlackFin |
| * |
| * Copyright (C) 2007 Marc Hoffman <marc.hoffman@analog.com> |
| * |
| * 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 |
| */ |
| /* |
| void ff_bfin_fdct (DCTELEM *buf); |
| |
| This implementation works only for 8x8 input. The range of input |
| must be -256 to 255 i.e. 8bit input represented in a 16bit data |
| word. The original data must be sign extended into the 16bit data |
| words. |
| |
| |
| Chen factorization of |
| |
| 8 |
| X(m) = sum (x(n) * cos ((2n+1)*m*pi/16)) |
| n=0 |
| |
| C4 |
| 0 --*-------------*0+7---*-----*0+3-------*-*-------------------> 0 |
| \ / \ / X S4,S4 |
| 1 --*-\---------/-*1+6---*-\-/-*1+2-------*-*-------------------> 4 |
| \ / \ -C4 C3 |
| 2 --*---\-----/---*2+5---*-/-\-*1-2---------------*-*-----------> 2 |
| \ / / \ X S3,-S3 |
| 3 --*-----\-/-----*3+4---*-----*0-3---------------*-*-----------> 6 |
| / C7 C3 |
| 4 --*-----/-\-----*3-4------------*-*4+5--*-----*---------------> 1 |
| / \ -C4 X \ /S7 C3 |
| 5 --*---/-----\---*2-5---*-*------*=*4-5----\-/------*-*--------> 5 |
| / \ X S4,S4 / X S3,-S3 |
| 6 --*-/---------\-*1-6---*-*------*=*7-6----/-\------*-*--------> 3 |
| / \ C4 X / \-S7 C3 |
| --*-------------*0-7------------*-*7+6--*-----*---------------> 7 |
| C7 |
| |
| Notation |
| Cn = cos(n*pi/8) used throughout the code. |
| |
| |
| Registers used: |
| R0, R1, R2, R3, R4, R5, R6,R7, P0, P1, P2, P3, P4, P5, A0, A1. |
| Other registers used: |
| I0, I1, I2, I3, B0, B2, B3, M0, M1, L3 registers and LC0. |
| |
| Input - r0 - pointer to start of DCTELEM *block |
| |
| Output - The DCT output coefficients in the DCTELEM *block |
| |
| Register constraint: |
| This code is called from jpeg_encode. |
| R6, R5, R4 if modified should be stored and restored. |
| |
| |
| Performance: (Timer version 0.6.33) |
| Code Size : 240 Bytes. |
| Memory Required : |
| Input Matrix : 8 * 8 * 2 Bytes. |
| Coefficients : 16 Bytes |
| Temporary matrix: 8 * 8 * 2 Bytes. |
| Cycle Count :26+{18+8*(14+2S)}*2 where S -> Stalls |
| (7.45 c/pel) |
| ----------------------------------------- |
| | Size | Forward DCT | Inverse DCT | |
| ----------------------------------------- |
| | 8x8 | 284 Cycles | 311 Cycles | |
| ----------------------------------------- |
| |
| Ck = int16(cos(k/16*pi)*32767+.5)/2 |
| #define C4 23170 |
| #define C3 13623 |
| #define C6 6270 |
| #define C7 3196 |
| |
| Sk = int16(sin(k/16*pi)*32767+.5)/2 |
| #define S4 11585 |
| #define S3 9102 |
| #define S6 15137 |
| #define S7 16069 |
| |
| the coefficients are ordered as follows: |
| short dct_coef[] |
| C4,S4, |
| C6,S6, |
| C7,S7, |
| S3,C3, |
| |
| ----------------------------------------------------------- |
| FFMPEG conformance testing results |
| ----------------------------------------------------------- |
| dct-test: modified with the following |
| dct_error("BFINfdct", 0, ff_bfin_fdct, fdct, test); |
| produces the following output: |
| |
| root:/u/ffmpeg/bhead/libavcodec> ./dct-test |
| ffmpeg DCT/IDCT test |
| |
| 2 -131 -6 -48 -36 33 -83 24 |
| 34 52 -24 -15 5 92 57 143 |
| -67 -43 -1 74 -16 5 -71 32 |
| -78 106 92 -34 -38 81 20 -18 |
| 7 -62 40 2 -15 90 -62 -83 |
| -83 1 -104 -13 43 -19 7 11 |
| -63 31 12 -29 83 72 21 10 |
| -17 -63 -15 73 50 -91 159 -14 |
| DCT BFINfdct: err_inf=2 err2=0.16425938 syserr=0.00795000 maxout=2098 blockSumErr=27 |
| DCT BFINfdct: 92.1 kdct/s |
| root:/u/ffmpeg/bhead/libavcodec> |
| |
| */ |
| |
| #include "config_bfin.h" |
| |
| #ifdef __FDPIC__ |
| .section .l1.data.B,"aw",@progbits |
| #else |
| .data |
| #endif |
| .align 4; |
| dct_coeff: |
| .short 0x5a82, 0x2d41, 0x187e, 0x3b21, 0x0c7c, 0x3ec5, 0x238e, 0x3537; |
| |
| #ifdef __FDPIC__ |
| .section .l1.data.A,"aw",@progbits |
| #endif |
| .align 4 |
| vtmp: .space 128 |
| |
| .text |
| DEFUN(fdct,mL1, |
| (DCTELEM *block)): |
| [--SP] = (R7:4, P5:3); // Push the registers onto the stack. |
| |
| b0 = r0; |
| RELOC(r0, P3, dct_coeff); |
| b3 = r0; |
| RELOC(r0, P3, vtmp); |
| b2 = r0; |
| |
| L3 = 16; // L3 is set to 16 to make the coefficient |
| // array Circular. |
| |
| |
| //---------------------------------------------------------------------------- |
| |
| /* |
| * I0, I1, and I2 registers are used to read the input data. I3 register is used |
| * to read the coefficients. P0 and P1 registers are used for writing the output |
| * data. |
| */ |
| M0 = 12 (X); // All these initializations are used in the |
| M1 = 16 (X); // modification of address offsets. |
| |
| M2 = 128 (X); |
| |
| P2 = 16; |
| P3 = 32 (X); |
| P4 = -110 (X); |
| P5 = -62 (X); |
| P0 = 2(X); |
| |
| |
| // Prescale the input to get the correct precision. |
| i0=b0; |
| i1=b0; |
| |
| lsetup (.0, .1) LC0 = P3; |
| r0=[i0++]; |
| .0: r1=r0<<3 (v) || r0=[i0++] ; |
| .1: [i1++]=r1; |
| |
| /* |
| * B0 points to the "in" buffer. |
| * B2 points to "temp" buffer in the first iteration. |
| */ |
| |
| lsetup (.2, .3) LC0 = P0; |
| .2: |
| I0 = B0; // I0 points to Input Element (0, 0). |
| I1 = B0; // Element 1 and 0 is read in R0. |
| I1 += M0 || R0 = [I0++]; // I1 points to Input Element (0, 6). |
| I2 = I1; // Element 6 is read into R3.H. |
| I2 -= 4 || R3.H = W[I1++]; // I2 points to Input Element (0, 4). |
| |
| I3 = B3; // I3 points to Coefficients. |
| P0 = B2; // P0 points to temporary array Element |
| // (0, 0). |
| P1 = B2; // P1 points to temporary array. |
| R7 = [P1++P2] || R2 = [I2++]; // P1 points to temporary array |
| // Element (1, 0). |
| // R7 is a dummy read. X4,X5 |
| // are read into R2. |
| R3.L = W[I1--]; // X7 is read into R3.L. |
| R1.H = W[I0++]; // X2 is read into R1.H. |
| |
| |
| /* |
| * X0 = (X0 + X7) / 2. |
| * X1 = (X1 + X6) / 2. |
| * X6 = (X1 - X6) / 2. |
| * X7 = (X0 - X7) / 2. |
| * It reads the data 3 in R1.L. |
| */ |
| |
| R0 = R0 +|+ R3, R3 = R0 -|- R3 || R1.L = W[I0++] || NOP; |
| |
| /* |
| * X2 = (X2 + X5) / 2. |
| * X3 = (X3 + X4) / 2. |
| * X4 = (X3 - X4) / 2. |
| * X5 = (X2 - X5) / 2. |
| * R7 = C4 = cos(4*pi/16) |
| */ |
| |
| R1 = R1 +|+ R2, R2 = R1 -|- R2 (CO) || NOP || R7 = [I3++]; |
| |
| /* |
| * At the end of stage 1 R0 has (1,0), R1 has (2,3), R2 has (4, 5) and |
| * R3 has (6,7). |
| * Where the notation (x, y) represents uper/lower half pairs. |
| */ |
| |
| /* |
| * X0 = X0 + X3. |
| * X1 = X1 + X2. |
| * X2 = X1 - X2. |
| * X3 = X0 - X3. |
| */ |
| R0 = R0 +|+ R1, R1 = R0 -|- R1; |
| |
| lsetup (.row0, .row1) LC1 = P2 >> 1; // 1d dct, loops 8x |
| .row0: |
| |
| /* |
| * This is part 2 computation continued..... |
| * A1 = X6 * cos(pi/4) |
| * A0 = X6 * cos(pi/4) |
| * A1 = A1 - X5 * cos(pi/4) |
| * A0 = A0 + X5 * cos(pi/4). |
| * The instruction W[I0] = R3.L is used for packing it to R2.L. |
| */ |
| |
| A1=R3.H*R7.l, A0=R3.H*R7.l || I1+=M1 || W[I0] = R3.L; |
| R4.H=(A1-=R2.L*R7.l), R4.L=(A0+=R2.L*R7.l) || I2+=M0 || NOP; |
| |
| /* R0 = (X1,X0) R1 = (X2,X3) R4 = (X5, X6). */ |
| |
| /* |
| * A1 = X0 * cos(pi/4) |
| * A0 = X0 * cos(pi/4) |
| * A1 = A1 - X1 * cos(pi/4) |
| * A0 = A0 + X1 * cos(pi/4) |
| * R7 = (C2,C6) |
| */ |
| A1=R0.L*R7.h, A0=R0.L*R7.h || NOP || R3.H=W[I1++]; |
| R5.H=(A1-=R0.H*R7.h),R5.L=(A0+=R0.H*R7.h) || R7=[I3++] || NOP; |
| |
| /* |
| * A1 = X2 * cos(3pi/8) |
| * A0 = X3 * cos(3pi/8) |
| * A1 = A1 + X3 * cos(pi/8) |
| * A0 = A0 - X2 * cos(pi/8) |
| * R3 = cos(pi/4) |
| * R7 = (cos(7pi/8),cos(pi/8)) |
| * X4 = X4 + X5. |
| * X5 = X4 - X5. |
| * X6 = X7 - X6. |
| * X7 = X7 + X6. |
| */ |
| A1=R1.H*R7.L, A0=R1.L*R7.L || W[P0++P3]=R5.L || R2.L=W[I0]; |
| R2=R2+|+R4, R4=R2-|-R4 || I0+=4 || R3.L=W[I1--]; |
| R6.H=(A1+=R1.L*R7.H),R6.L=(A0 -= R1.H * R7.H) || I0+=4 || R7=[I3++]; |
| |
| /* R2 = (X4, X7) R4 = (X5,X6) R5 = (X1, X0) R6 = (X2,X3). */ |
| |
| /* |
| * A1 = X4 * cos(7pi/16) |
| * A0 = X7 * cos(7pi/16) |
| * A1 = A1 + X7 * cos(pi/16) |
| * A0 = A0 - X4 * cos(pi/16) |
| */ |
| |
| A1=R2.H*R7.L, A0=R2.L*R7.L || W[P0++P3]=R6.H || R0=[I0++]; |
| R2.H=(A1+=R2.L*R7.H),R2.L=(A0-=R2.H*R7.H) || W[P0++P3]=R5.H || R7=[I3++]; |
| |
| /* |
| * A1 = X5 * cos(3pi/16) |
| * A0 = X6 * cos(3pi/16) |
| * A1 = A1 + X6 * cos(5pi/16) |
| * A0 = A0 - X5 * cos(5pi/16) |
| * The output values are written. |
| */ |
| |
| A1=R4.H*R7.H, A0=R4.L*R7.H || W[P0++P2]=R6.L || R1.H=W[I0++]; |
| R4.H=(A1+=R4.L*R7.L),R4.L=(A0-=R4.H*R7.L) || W[P0++P4]=R2.L || R1.L=W[I0++]; |
| |
| |
| /* Beginning of next stage, **pipelined** + drain and store the |
| rest of the column store. */ |
| |
| R0=R0+|+R3,R3=R0-|-R3 || W[P1++P3]=R2.H || R2=[I2++]; |
| R1=R1+|+R2,R2=R1-|-R2 (CO) || W[P1++P3]=R4.L || R7=[I3++]; |
| .row1: R0=R0+|+R1,R1=R0-|-R1 || W[P1++P5]=R4.H || NOP; |
| |
| // Exchange input with output. |
| B1 = B0; |
| B0 = B2; |
| .3: B2 = B1; |
| |
| L3=0; |
| (r7:4,p5:3) = [sp++]; |
| RTS; |
| DEFUN_END(fdct) |
| |
