CPU features for RISC-V architecture

[denzen84]

Hi!

I built dump1090-fa for RISC-V CPU architecture using MangoPi MQ-Pro board with Alwinner D1 CPU. This CPU has pretty low perfomace (1GHz core) for dump1090. System load in dump1090 task varies from 70% to 90% (!). Hope there are people who can create starch optimized DSP code for this architecture.

generated by /usr/lib/dump1090-fa/starch-benchmark -i 5 -r /tmp/wisdom.kM5ASo/wisdom.initial -o /tmp/wisdom.kM5ASo/wisdom.local

count_above_u16 generic_generic # 1601 ns/call

count_above_u16_aligned generic_generic # 1601 ns/call

magnitude_power_uc8 lookup_unroll_4_generic # 6510792 ns/call
magnitude_power_uc8 twopass_generic # 7355395 ns/call
magnitude_power_uc8 lookup_generic # 12311608 ns/call

magnitude_power_uc8_aligned lookup_unroll_4_generic # 6524227 ns/call
magnitude_power_uc8_aligned twopass_generic # 7389099 ns/call
magnitude_power_uc8_aligned lookup_generic # 12299636 ns/call

magnitude_sc16 exact_float_generic # 51198765 ns/call
magnitude_sc16 exact_u32_generic # 51425345 ns/call

magnitude_sc16_aligned exact_float_generic # 51085431 ns/call
magnitude_sc16_aligned exact_u32_generic # 51120352 ns/call

magnitude_sc16q11 exact_u32_generic # 12760473 ns/call
magnitude_sc16q11 exact_float_generic # 12919983 ns/call
magnitude_sc16q11 11bit_table_generic # 24520649 ns/call
magnitude_sc16q11 12bit_table_generic # 26435000 ns/call

magnitude_sc16q11_aligned exact_u32_generic # 12808275 ns/call
magnitude_sc16q11_aligned exact_float_generic # 12962918 ns/call
magnitude_sc16q11_aligned 11bit_table_generic # 24499023 ns/call
magnitude_sc16q11_aligned 12bit_table_generic # 26387828 ns/call

magnitude_uc8 lookup_unroll_4_generic # 5899120 ns/call
magnitude_uc8 lookup_generic # 11956921 ns/call
magnitude_uc8 exact_generic # 15051605 ns/call

magnitude_uc8_aligned lookup_unroll_4_generic # 5892454 ns/call
magnitude_uc8_aligned lookup_generic # 11961086 ns/call
magnitude_uc8_aligned exact_generic # 15016325 ns/call

mean_power_u16 u32_generic # 1494011 ns/call
mean_power_u16 u64_generic # 1650544 ns/call
mean_power_u16 float_generic # 1652144 ns/call

mean_power_u16_aligned u32_generic # 1494788 ns/call
mean_power_u16_aligned float_generic # 1653474 ns/call
mean_power_u16_aligned u64_generic # 1655373 ns/call