s32_div_u32_round_down
s32_div_u32_round_down(csi_idx, MAX_TONE_NUM, &csi_tone_idx);
nbi_idx = s32_div_u32_round_down(freq_diff, CARRIER_SPACING_312_5,
s32_div_u32_round_down(nbi_idx + 32, 64, &nbi_tone_idx);
s32_div_u32_round_down(nbi_idx, tone_para, &nbi_tone_idx);
s32_div_u32_round_down(csi_idx, MAX_TONE_NUM, &csi_tone_idx);
s32_div_u32_round_down(csi_idx, MAX_TONE_NUM, &csi_tone_idx);
nbi_idx = s32_div_u32_round_down(freq_diff, CARRIER_SPACING_312_5, &nbi_frac_idx);
s32_div_u32_round_down(nbi_idx + 32, 64, &nbi_tone_idx);
s32_div_u32_round_down(nbi_idx, tone_para, &nbi_tone_idx);
s32_div_u32_round_down(csi_idx, MAX_TONE_NUM, &csi_tone_idx);
nbi_idx = s32_div_u32_round_down(freq_diff, CARRIER_SPACING_312_5,
s32_div_u32_round_down(nbi_idx + 32, 64, &nbi_tone_idx);
s32_div_u32_round_down(nbi_idx, tone_para, &nbi_tone_idx);
return s32_div_u32_round_down(dividend + divisor / 2, divisor, NULL);