/* $NetBSD: smeartest.c,v 1.3 2024/08/18 20:47:27 christos Exp $ */ #include #include #include #include /* * we want to test a refid format of: * 254.x.y.x * * where x.y.z are 24 bits containing 2 (signed) integer bits * and 22 fractional bits. * * we want functions to convert to/from this format, with unit tests. * * Interesting test cases include: * 254.0.0.0 * 254.0.0.1 * 254.127.255.255 * 254.128.0.0 * 254.255.255.255 */ char *progname = ""; l_fp convertRefIDToLFP(uint32_t r); uint32_t convertLFPToRefID(l_fp num); /* * The smear data in the refid is the bottom 3 bytes of the refid, * 2 bits of integer * 22 bits of fraction */ l_fp convertRefIDToLFP(uint32_t r) { l_fp temp; r = ntohl(r); printf("%03d %08x: ", (r >> 24) & 0xFF, (r & 0x00FFFFFF) ); temp.l_uf = (r << 10); /* 22 fractional bits */ temp.l_ui = (r >> 22) & 0x3; temp.l_ui |= ~(temp.l_ui & 2) + 1; return temp; } uint32_t convertLFPToRefID(l_fp num) { uint32_t temp; /* round the input with the highest bit to shift out from the * fraction, then keep just two bits from the integral part. * * TODO: check for overflows; should we clamp/saturate or just * complain? */ L_ADDUF(&num, 0x200); num.l_ui &= 3; /* combine integral and fractional part to 24 bits */ temp = (num.l_ui << 22) | (num.l_uf >> 10); /* put in the leading 254.0.0.0 */ temp |= UINT32_C(0xFE000000); printf("%03d %08x: ", (temp >> 24) & 0xFF, (temp & 0x00FFFFFF) ); return htonl(temp); } /* Tests start here */ void rtol(uint32_t r); void rtol(uint32_t r) { l_fp l; printf("rtol: "); l = convertRefIDToLFP(htonl(r)); printf("refid %#x, smear %s\n", r, lfptoa(&l, 8)); return; } void rtoltor(uint32_t r); void rtoltor(uint32_t r) { l_fp l; printf("rtoltor: "); l = convertRefIDToLFP(htonl(r)); r = convertLFPToRefID(l); printf("smear %s, refid %#.8x\n", lfptoa(&l, 8), ntohl(r)); return; } void ltor(l_fp l); void ltor(l_fp l) { uint32_t r; printf("ltor: "); r = convertLFPToRefID(l); printf("smear %s, refid %#.8x\n", lfptoa(&l, 8), ntohl(r)); return; } int main(void) { l_fp l; int rc; init_lib(); rtol(0xfe800000); rtol(0xfe800001); rtol(0xfe8ffffe); rtol(0xfe8fffff); rtol(0xfef00000); rtol(0xfef00001); rtol(0xfefffffe); rtol(0xfeffffff); rtol(0xfe000000); rtol(0xfe000001); rtol(0xfe6ffffe); rtol(0xfe6fffff); rtol(0xfe700000); rtol(0xfe700001); rtol(0xfe7ffffe); rtol(0xfe7fffff); rtoltor(0xfe800000); rtoltor(0xfe800001); rtoltor(0xfe8ffffe); rtoltor(0xfe8fffff); rtoltor(0xfef00000); rtoltor(0xfef00001); rtoltor(0xfefffffe); rtoltor(0xfeffffff); rtoltor(0xfe000000); rtoltor(0xfe000001); rtoltor(0xfe6ffffe); rtoltor(0xfe6fffff); rtoltor(0xfe700000); rtoltor(0xfe700001); rtoltor(0xfe7ffffe); rtoltor(0xfe7fffff); rc = atolfp("-.932087", &l); INSIST(1 == rc); ltor(l); rtol(0xfec458b0); printf("%x -> %d.%d.%d.%d\n", 0xfec458b0, 0xfe, 0xc4, 0x58, 0xb0); return 0; }