pal_pred

Benchmarks:

- Kendryte K230:
pal_pred_w4_8bpc_c:        115.6 ( 1.00x)
pal_pred_w4_8bpc_rvv:      331.4 ( 0.35x)
pal_pred_w4_16bpc_c:       140.8 ( 1.00x)
pal_pred_w4_16bpc_rvv:     247.9 ( 0.57x)
pal_pred_w8_8bpc_c:        334.9 ( 1.00x)
pal_pred_w8_8bpc_rvv:      520.8 ( 0.64x)
pal_pred_w8_16bpc_c:       412.7 ( 1.00x)
pal_pred_w8_16bpc_rvv:     386.2 ( 1.07x)
pal_pred_w16_8bpc_c:      1044.4 ( 1.00x)
pal_pred_w16_8bpc_rvv:     842.8 ( 1.24x)
pal_pred_w16_16bpc_c:     1300.3 ( 1.00x)
pal_pred_w16_16bpc_rvv:    619.9 ( 2.10x)
pal_pred_w32_8bpc_c:      2452.8 ( 1.00x)
pal_pred_w32_8bpc_rvv:    1016.1 ( 2.41x)
pal_pred_w32_16bpc_c:     3072.1 ( 1.00x)
pal_pred_w32_16bpc_rvv:   1440.5 ( 2.13x)
pal_pred_w64_8bpc_c:      6015.8 ( 1.00x)
pal_pred_w64_8bpc_rvv:    2505.5 ( 2.40x)
pal_pred_w64_16bpc_c:     7552.4 ( 1.00x)
pal_pred_w64_16bpc_rvv:   3512.7 ( 2.15x)

- Banana Pi BPI-F3:
pal_pred_w4_8bpc_c:        102.2 ( 1.00x)
pal_pred_w4_8bpc_rvv:      511.2 ( 0.20x)
pal_pred_w4_16bpc_c:       137.7 ( 1.00x)
pal_pred_w4_16bpc_rvv:     330.9 ( 0.42x)
pal_pred_w8_8bpc_c:        289.2 ( 1.00x)
pal_pred_w8_8bpc_rvv:      819.6 ( 0.35x)
pal_pred_w8_16bpc_c:       402.6 ( 1.00x)
pal_pred_w8_16bpc_rvv:     520.7 ( 0.77x)
pal_pred_w16_8bpc_c:       894.5 ( 1.00x)
pal_pred_w16_8bpc_rvv:    1326.6 ( 0.67x)
pal_pred_w16_16bpc_c:     1268.6 ( 1.00x)
pal_pred_w16_16bpc_rvv:    845.8 ( 1.50x)
pal_pred_w32_8bpc_c:      2094.5 ( 1.00x)
pal_pred_w32_8bpc_rvv:    1610.9 ( 1.30x)
pal_pred_w32_16bpc_c:     2999.4 ( 1.00x)
pal_pred_w32_16bpc_rvv:   1029.8 ( 2.91x)
pal_pred_w64_8bpc_c:      5128.0 ( 1.00x)
pal_pred_w64_8bpc_rvv:    2000.8 ( 2.56x)
pal_pred_w64_16bpc_c:     7375.0 ( 1.00x)
pal_pred_w64_16bpc_rvv:   2518.2 ( 2.93x)