+ CONST_BITS+PASS1_BITS);
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
+/*
+ * The secret of DCT2-4-8 is really simple -- you do the usual 1-DCT
+ * on the rows and then, instead of doing even and odd, part on the colums
+ * you do even part two times.
+ */
+GLOBAL(void)
+ff_fdct248_islow (DCTELEM * data)
+{
+ int_fast32_t tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ int_fast32_t tmp10, tmp11, tmp12, tmp13;
+ int_fast32_t z1;
+ DCTELEM *dataptr;
+ int ctr;
+ SHIFT_TEMPS
+
+ row_fdct(data);
+
+ /* Pass 2: process columns.
+ * We remove the PASS1_BITS scaling, but leave the results scaled up
+ * by an overall factor of 8.
+ */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1];
+ tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3];
+ tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5];
+ tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7];
+ tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1];
+ tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3];
+ tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5];
+ tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7];
+
+ tmp10 = tmp0 + tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ tmp13 = tmp0 - tmp3;
+
+ dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS);
+ dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS);
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
+ dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
+ CONST_BITS+PASS1_BITS);
+
+ tmp10 = tmp4 + tmp7;
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp5 - tmp6;
+ tmp13 = tmp4 - tmp7;
+
+ dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS);
+ dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS);
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
+ dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
+ CONST_BITS+PASS1_BITS);
+
+ dataptr++; /* advance pointer to next column */