dsputil_altivec.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    register vector signed short line6C = vec_sub(line2B, line6B);
    register vector signed short line3C = vec_add(line3B, line7B);
    register vector signed short line7C = vec_sub(line3B, line7B);

    vsum = vec_sum4s(vec_abs(line0C), vec_splat_s32(0));
    vsum = vec_sum4s(vec_abs(line1C), vsum);
    vsum = vec_sum4s(vec_abs(line2C), vsum);
    vsum = vec_sum4s(vec_abs(line3C), vsum);
    vsum = vec_sum4s(vec_abs(line4C), vsum);
    vsum = vec_sum4s(vec_abs(line5C), vsum);
    vsum = vec_sum4s(vec_abs(line6C), vsum);
    vsum = vec_sum4s(vec_abs(line7C), vsum);
    vsum = vec_sums(vsum, (vector signed int)vzero);
    vsum = vec_splat(vsum, 3);
    vec_ste(vsum, 0, &sum);
  }
POWERPC_PERF_STOP_COUNT(altivec_hadamard8_diff8x8_num, 1);
  return sum;
}

/*
  16x8 works with 16 elements ; it allows to avoid replicating
  loads, and give the compiler more rooms for scheduling.
  It's only used from inside hadamard8_diff16_altivec.

  Unfortunately, it seems gcc-3.3 is a bit dumb, and
  the compiled code has a LOT of spill code, it seems
  gcc (unlike xlc) cannot keep everything in registers
  by itself. The following code include hand-made
  registers allocation. It's not clean, but on
  a 7450 the resulting code is much faster (best case
  fall from 700+ cycles to 550).

  xlc doesn't add spill code, but it doesn't know how to
  schedule for the 7450, and its code isn't much faster than
  gcc-3.3 on the 7450 (but uses 25% less instructions...)

  On the 970, the hand-made RA is still a win (arount 690
  vs. around 780), but xlc goes to around 660 on the
  regular C code...
*/

static int hadamard8_diff16x8_altivec(/*MpegEncContext*/ void *s, uint8_t *dst, uint8_t *src, int stride, int h) {
    int sum;
    register vector signed short
        temp0 REG_v(v0),
        temp1 REG_v(v1),
        temp2 REG_v(v2),
        temp3 REG_v(v3),
        temp4 REG_v(v4),
        temp5 REG_v(v5),
        temp6 REG_v(v6),
        temp7 REG_v(v7);
    register vector signed short
        temp0S REG_v(v8),
        temp1S REG_v(v9),
        temp2S REG_v(v10),
        temp3S REG_v(v11),
        temp4S REG_v(v12),
        temp5S REG_v(v13),
        temp6S REG_v(v14),
        temp7S REG_v(v15);
    register const vector unsigned char vzero REG_v(v31)=
        (const vector unsigned char)vec_splat_u8(0);
  {
    register const vector signed short vprod1 REG_v(v16)=
        (const vector signed short)AVV( 1,-1, 1,-1, 1,-1, 1,-1);
    register const vector signed short vprod2 REG_v(v17)=
        (const vector signed short)AVV( 1, 1,-1,-1, 1, 1,-1,-1);
    register const vector signed short vprod3 REG_v(v18)=
        (const vector signed short)AVV( 1, 1, 1, 1,-1,-1,-1,-1);
    register const vector unsigned char perm1 REG_v(v19)=
        (const vector unsigned char)
        AVV(0x02, 0x03, 0x00, 0x01, 0x06, 0x07, 0x04, 0x05,
            0x0A, 0x0B, 0x08, 0x09, 0x0E, 0x0F, 0x0C, 0x0D);
    register const vector unsigned char perm2 REG_v(v20)=
        (const vector unsigned char)
        AVV(0x04, 0x05, 0x06, 0x07, 0x00, 0x01, 0x02, 0x03,
            0x0C, 0x0D, 0x0E, 0x0F, 0x08, 0x09, 0x0A, 0x0B);
    register const vector unsigned char perm3 REG_v(v21)=
        (const vector unsigned char)
        AVV(0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
            0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07);

#define ONEITERBUTTERFLY(i, res1, res2)                                 \
    {                                                                   \
      register vector unsigned char src1 REG_v(v22),                    \
                                    src2 REG_v(v23),                    \
                                    dst1 REG_v(v24),                    \
                                    dst2 REG_v(v25),                    \
                                    srcO REG_v(v22),                    \
                                    dstO REG_v(v23);                    \
                                                                        \
      register vector signed short  srcV REG_v(v24),                    \
                                    dstV REG_v(v25),                    \
                                    srcW REG_v(v26),                    \
                                    dstW REG_v(v27),                    \
                                    but0 REG_v(v28),                    \
                                    but0S REG_v(v29),                   \
                                    op1 REG_v(v30),                     \
                                    but1 REG_v(v22),                    \
                                    op1S REG_v(v23),                    \
                                    but1S REG_v(v24),                   \
                                    op2 REG_v(v25),                     \
                                    but2 REG_v(v26),                    \
                                    op2S REG_v(v27),                    \
                                    but2S REG_v(v28),                   \
                                    op3 REG_v(v29),                     \
                                    op3S REG_v(v30);                    \
                                                                        \
      src1 = vec_ld(stride * i, src);                                   \
      src2 = vec_ld((stride * i) + 16, src);                            \
      srcO = vec_perm(src1, src2, vec_lvsl(stride * i, src));           \
      dst1 = vec_ld(stride * i, dst);                                   \
      dst2 = vec_ld((stride * i) + 16, dst);                            \
      dstO = vec_perm(dst1, dst2, vec_lvsl(stride * i, dst));           \
      /* promote the unsigned chars to signed shorts */                 \
      srcV =                                                            \
        (vector signed short)vec_mergeh((vector signed char)vzero,      \
        (vector signed char)srcO);                                      \
      dstV =                                                            \
        (vector signed short)vec_mergeh((vector signed char)vzero,      \
        (vector signed char)dstO);                                      \
      srcW =                                                            \
        (vector signed short)vec_mergel((vector signed char)vzero,      \
        (vector signed char)srcO);                                      \
      dstW =                                                            \
        (vector signed short)vec_mergel((vector signed char)vzero,      \
        (vector signed char)dstO);                                      \
      /* substractions inside the first butterfly */                    \
      but0 = vec_sub(srcV, dstV);                                       \
      but0S = vec_sub(srcW, dstW);                                      \
      op1 = vec_perm(but0, but0, perm1);                                \
      but1 = vec_mladd(but0, vprod1, op1);                              \
      op1S = vec_perm(but0S, but0S, perm1);                             \
      but1S = vec_mladd(but0S, vprod1, op1S);                           \
      op2 = vec_perm(but1, but1, perm2);                                \
      but2 = vec_mladd(but1, vprod2, op2);                              \
      op2S = vec_perm(but1S, but1S, perm2);                             \
      but2S = vec_mladd(but1S, vprod2, op2S);                           \
      op3 = vec_perm(but2, but2, perm3);                                \
      res1 = vec_mladd(but2, vprod3, op3);                              \
      op3S = vec_perm(but2S, but2S, perm3);                             \
      res2 = vec_mladd(but2S, vprod3, op3S);                            \
    }
    ONEITERBUTTERFLY(0, temp0, temp0S);
    ONEITERBUTTERFLY(1, temp1, temp1S);
    ONEITERBUTTERFLY(2, temp2, temp2S);
    ONEITERBUTTERFLY(3, temp3, temp3S);
    ONEITERBUTTERFLY(4, temp4, temp4S);
    ONEITERBUTTERFLY(5, temp5, temp5S);
    ONEITERBUTTERFLY(6, temp6, temp6S);
    ONEITERBUTTERFLY(7, temp7, temp7S);
  }
#undef ONEITERBUTTERFLY
  {
    register vector signed int vsum;
    register vector signed short line0S, line1S, line2S, line3S, line4S,
                                 line5S, line6S, line7S, line0BS,line2BS,
                                 line1BS,line3BS,line4BS,line6BS,line5BS,
                                 line7BS,line0CS,line4CS,line1CS,line5CS,
                                 line2CS,line6CS,line3CS,line7CS;

    register vector signed short line0 = vec_add(temp0, temp1);
    register vector signed short line1 = vec_sub(temp0, temp1);
    register vector signed short line2 = vec_add(temp2, temp3);
    register vector signed short line3 = vec_sub(temp2, temp3);
    register vector signed short line4 = vec_add(temp4, temp5);
    register vector signed short line5 = vec_sub(temp4, temp5);
    register vector signed short line6 = vec_add(temp6, temp7);
    register vector signed short line7 = vec_sub(temp6, temp7);

    register vector signed short line0B = vec_add(line0, line2);
    register vector signed short line2B = vec_sub(line0, line2);
    register vector signed short line1B = vec_add(line1, line3);
    register vector signed short line3B = vec_sub(line1, line3);
    register vector signed short line4B = vec_add(line4, line6);
    register vector signed short line6B = vec_sub(line4, line6);
    register vector signed short line5B = vec_add(line5, line7);
    register vector signed short line7B = vec_sub(line5, line7);

    register vector signed short line0C = vec_add(line0B, line4B);
    register vector signed short line4C = vec_sub(line0B, line4B);
    register vector signed short line1C = vec_add(line1B, line5B);
    register vector signed short line5C = vec_sub(line1B, line5B);
    register vector signed short line2C = vec_add(line2B, line6B);
    register vector signed short line6C = vec_sub(line2B, line6B);
    register vector signed short line3C = vec_add(line3B, line7B);
    register vector signed short line7C = vec_sub(line3B, line7B);

    vsum = vec_sum4s(vec_abs(line0C), vec_splat_s32(0));
    vsum = vec_sum4s(vec_abs(line1C), vsum);
    vsum = vec_sum4s(vec_abs(line2C), vsum);
    vsum = vec_sum4s(vec_abs(line3C), vsum);
    vsum = vec_sum4s(vec_abs(line4C), vsum);
    vsum = vec_sum4s(vec_abs(line5C), vsum);
    vsum = vec_sum4s(vec_abs(line6C), vsum);
    vsum = vec_sum4s(vec_abs(line7C), vsum);

    line0S = vec_add(temp0S, temp1S);
    line1S = vec_sub(temp0S, temp1S);
    line2S = vec_add(temp2S, temp3S);
    line3S = vec_sub(temp2S, temp3S);
    line4S = vec_add(temp4S, temp5S);
    line5S = vec_sub(temp4S, temp5S);
    line6S = vec_add(temp6S, temp7S);
    line7S = vec_sub(temp6S, temp7S);

    line0BS = vec_add(line0S, line2S);
    line2BS = vec_sub(line0S, line2S);
    line1BS = vec_add(line1S, line3S);
    line3BS = vec_sub(line1S, line3S);
    line4BS = vec_add(line4S, line6S);
    line6BS = vec_sub(line4S, line6S);
    line5BS = vec_add(line5S, line7S);
    line7BS = vec_sub(line5S, line7S);

    line0CS = vec_add(line0BS, line4BS);
    line4CS = vec_sub(line0BS, line4BS);
    line1CS = vec_add(line1BS, line5BS);
    line5CS = vec_sub(line1BS, line5BS);
    line2CS = vec_add(line2BS, line6BS);
    line6CS = vec_sub(line2BS, line6BS);
    line3CS = vec_add(line3BS, line7BS);
    line7CS = vec_sub(line3BS, line7BS);

    vsum = vec_sum4s(vec_abs(line0CS), vsum);
    vsum = vec_sum4s(vec_abs(line1CS), vsum);
    vsum = vec_sum4s(vec_abs(line2CS), vsum);
    vsum = vec_sum4s(vec_abs(line3CS), vsum);
    vsum = vec_sum4s(vec_abs(line4CS), vsum);
    vsum = vec_sum4s(vec_abs(line5CS), vsum);
    vsum = vec_sum4s(vec_abs(line6CS), vsum);
    vsum = vec_sum4s(vec_abs(line7CS), vsum);
    vsum = vec_sums(vsum, (vector signed int)vzero);
    vsum = vec_splat(vsum, 3);
    vec_ste(vsum, 0, &sum);
  }
  return sum;
}

int hadamard8_diff16_altivec(/*MpegEncContext*/ void *s, uint8_t *dst, uint8_t *src, int stride, int h){
POWERPC_PERF_DECLARE(altivec_hadamard8_diff16_num, 1);
    int score;
POWERPC_PERF_START_COUNT(altivec_hadamard8_diff16_num, 1);
    score = hadamard8_diff16x8_altivec(s, dst, src, stride, 8);
    if (h==16) {
        dst += 8*stride;
        src += 8*stride;
        score += hadamard8_diff16x8_altivec(s, dst, src, stride, 8);
    }
POWERPC_PERF_STOP_COUNT(altivec_hadamard8_diff16_num, 1);
    return score;
}

static void vorbis_inverse_coupling_altivec(float *mag, float *ang,
                                            int blocksize)
{
    int i;
    vector float m, a;
    vector bool int t0, t1;
    const vector unsigned int v_31 = //XXX
        vec_add(vec_add(vec_splat_u32(15),vec_splat_u32(15)),vec_splat_u32(1));
    for(i=0; i<blocksize; i+=4) {
        m = vec_ld(0, mag+i);
        a = vec_ld(0, ang+i);
        t0 = vec_cmple(m, (vector float)vec_splat_u32(0));
        t1 = vec_cmple(a, (vector float)vec_splat_u32(0));
        a = vec_xor(a, (vector float) vec_sl((vector unsigned int)t0, v_31));
        t0 = (vector bool int)vec_and(a, t1);
        t1 = (vector bool int)vec_andc(a, t1);
        a = vec_sub(m, (vector float)t1);
        m = vec_add(m, (vector float)t0);
        vec_stl(a, 0, ang+i);
        vec_stl(m, 0, mag+i);
    }
}

/* next one assumes that ((line_size % 8) == 0) */
void avg_pixels8_xy2_altivec(uint8_t *block, const uint8_t *pixels, int line_size, int h)
{
POWERPC_PERF_DECLARE(altivec_avg_pixels8_xy2_num, 1);
    register int i;
    register vector unsigned char pixelsv1, pixelsv2, pixelsavg;
    register vector unsigned char blockv, temp1, temp2, blocktemp;
    register vector unsigned short pixelssum1, pixelssum2, temp3;

    register const vector unsigned char vczero = (const vector unsigned char)
                                        vec_splat_u8(0);
    register const vector unsigned short vctwo = (const vector unsigned short)
                                        vec_splat_u16(2);

    temp1 = vec_ld(0, pixels);
    temp2 = vec_ld(16, pixels);
    pixelsv1 = vec_perm(temp1, temp2, vec_lvsl(0, pixels));
    if ((((unsigned long)pixels) & 0x0000000F) ==  0x0000000F) {
        pixelsv2 = temp2;
    } else {
        pixelsv2 = vec_perm(temp1, temp2, vec_lvsl(1, pixels));
    }
    pixelsv1 = vec_mergeh(vczero, pixelsv1);
    pixelsv2 = vec_mergeh(vczero, pixelsv2);
    pixelssum1 = vec_add((vector unsigned short)pixelsv1,
                         (vector unsigned short)pixelsv2);
    pixelssum1 = vec_add(pixelssum1, vctwo);

POWERPC_PERF_START_COUNT(altivec_avg_pixels8_xy2_num, 1);
    for (i = 0; i < h ; i++) {
        int rightside = ((unsigned long)block & 0x0000000F);
        blockv = vec_ld(0, block);

        temp1 = vec_ld(line_size, pixels);
        temp2 = vec_ld(line_size + 16, pixels);
        pixelsv1 = vec_perm(temp1, temp2, vec_lvsl(line_size, pixels));
        if (((((unsigned long)pixels) + line_size) & 0x0000000F) ==  0x0000000F)
        {
            pixelsv2 = temp2;
        } else {
            pixelsv2 = vec_perm(temp1, temp2, vec_lvsl(line_size + 1, pixels));
        }

        pixelsv1 = vec_mergeh(vczero, pixelsv1);
        pixelsv2 = vec_mergeh(vczero, pixelsv2);
        pixelssum2 = vec_add((vector unsigned short)pixelsv1,
                             (vector unsigned short)pixelsv2);
        temp3 = vec_add(pixelssum1, pixelssum2);
        temp3 = vec_sra(temp3, vctwo);
        pixelssum1 = vec_add(pixelssum2, vctwo);
        pixelsavg = vec_packsu(temp3, (vector unsigned short) vczero);

        if (rightside) {
            blocktemp = vec_perm(blockv, pixelsavg, vcprm(0, 1, s0, s1));
        } else {
            blocktemp = vec_perm(blockv, pixelsavg, vcprm(s0, s1, 2, 3));
        }

        blockv = vec_avg(blocktemp, blockv);
        vec_st(blockv, 0, block);

        block += line_size;
        pixels += line_size;
    }

POWERPC_PERF_STOP_COUNT(altivec_avg_pixels8_xy2_num, 1);
}

void dsputil_init_altivec(DSPContext* c, AVCodecContext *avctx)
{
    c->pix_abs[0][1] = sad16_x2_altivec;
    c->pix_abs[0][2] = sad16_y2_altivec;
    c->pix_abs[0][3] = sad16_xy2_altivec;
    c->pix_abs[0][0] = sad16_altivec;
    c->pix_abs[1][0] = sad8_altivec;
    c->sad[0]= sad16_altivec;
    c->sad[1]= sad8_altivec;
    c->pix_norm1 = pix_norm1_altivec;
    c->sse[1]= sse8_altivec;
    c->sse[0]= sse16_altivec;
    c->pix_sum = pix_sum_altivec;
    c->diff_pixels = diff_pixels_altivec;
    c->get_pixels = get_pixels_altivec;
    c->add_bytes= add_bytes_altivec;
    c->put_pixels_tab[0][0] = put_pixels16_altivec;
    /* the two functions do the same thing, so use the same code */
    c->put_no_rnd_pixels_tab[0][0] = put_pixels16_altivec;
    c->avg_pixels_tab[0][0] = avg_pixels16_altivec;
    c->avg_pixels_tab[1][0] = avg_pixels8_altivec;
    c->avg_pixels_tab[1][3] = avg_pixels8_xy2_altivec;
    c->put_pixels_tab[1][3] = put_pixels8_xy2_altivec;
    c->put_no_rnd_pixels_tab[1][3] = put_no_rnd_pixels8_xy2_altivec;
    c->put_pixels_tab[0][3] = put_pixels16_xy2_altivec;
    c->put_no_rnd_pixels_tab[0][3] = put_no_rnd_pixels16_xy2_altivec;

    c->hadamard8_diff[0] = hadamard8_diff16_altivec;
    c->hadamard8_diff[1] = hadamard8_diff8x8_altivec;
    if (ENABLE_VORBIS_DECODER)
        c->vorbis_inverse_coupling = vorbis_inverse_coupling_altivec;
}