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fixeria gerrit-no-reply at lists.osmocom.orgfixeria has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/18244 ) Change subject: libosmogsm: import hopping sequence generation code ...................................................................... libosmogsm: import hopping sequence generation code This implementation is taken from OsmocomBB, in particular from: target/firmware/layer1/rfch.c Change return type to uint16_t, because neither ARFCN, nor MAI can be negative. Add prefix 'gsm0502_' to the function's name. Change-Id: I8aba1578cc9d1bd89d4f5d33a6e8fedc8bea789a Related: OS#4546 --- M include/osmocom/gsm/gsm0502.h M src/gsm/gsm0502.c M src/gsm/libosmogsm.map 3 files changed, 58 insertions(+), 0 deletions(-) Approvals: laforge: Looks good to me, approved tnt: Looks good to me, but someone else must approve Jenkins Builder: Verified diff --git a/include/osmocom/gsm/gsm0502.h b/include/osmocom/gsm/gsm0502.h index c9901df..cb993dc 100644 --- a/include/osmocom/gsm/gsm0502.h +++ b/include/osmocom/gsm/gsm0502.h @@ -47,3 +47,7 @@ }; uint32_t gsm0502_fn_remap(uint32_t fn, enum gsm0502_fn_remap_channel channel); + +uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t, + uint8_t hsn, uint8_t maio, + size_t n, const uint16_t *ma); diff --git a/src/gsm/gsm0502.c b/src/gsm/gsm0502.c index 5c5aa12..7ab6343 100644 --- a/src/gsm/gsm0502.c +++ b/src/gsm/gsm0502.c @@ -2,6 +2,8 @@ * Paging helper code */ /* * (C) 2009 by Holger Hans Peter Freyther <zecke at selfish.org> + * (C) 2010 by Sylvain Munaut <tnt at 246tNt.com> + * * All Rights Reserved * * SPDX-License-Identifier: GPL-2.0+ @@ -201,3 +203,54 @@ return fn_map; } + +/* Magic numbers (RNTABLE) for pseudo-random hopping sequence generation. */ +static const uint8_t rn_table[114] = { + 48, 98, 63, 1, 36, 95, 78, 102, 94, 73, + 0, 64, 25, 81, 76, 59, 124, 23, 104, 100, + 101, 47, 118, 85, 18, 56, 96, 86, 54, 2, + 80, 34, 127, 13, 6, 89, 57, 103, 12, 74, + 55, 111, 75, 38, 109, 71, 112, 29, 11, 88, + 87, 19, 3, 68, 110, 26, 33, 31, 8, 45, + 82, 58, 40, 107, 32, 5, 106, 92, 62, 67, + 77, 108, 122, 37, 60, 66, 121, 42, 51, 126, + 117, 114, 4, 90, 43, 52, 53, 113, 120, 72, + 16, 49, 7, 79, 119, 61, 22, 84, 9, 97, + 91, 15, 21, 24, 46, 39, 93, 105, 65, 70, + 125, 99, 17, 123, +}; + +/*! Hopping sequence generation as per 3GPP TS 45.002, section 6.2.3. */ +uint16_t gsm0502_hop_seq_gen(const struct gsm_time *t, + uint8_t hsn, uint8_t maio, + size_t n, const uint16_t *ma) +{ + unsigned int mai; + + if (hsn == 0) { + /* cyclic hopping */ + mai = (t->fn + maio) % n; + } else { + /* pseudo random hopping */ + int m, mp, tp, s, pnm; + + pnm = (n >> 0) | (n >> 1) + | (n >> 2) | (n >> 3) + | (n >> 4) | (n >> 5) + | (n >> 6); + + m = t->t2 + rn_table[(hsn ^ (t->t1 & 63)) + t->t3]; + mp = m & pnm; + + if (mp < n) + s = mp; + else { + tp = t->t3 & pnm; + s = (mp + tp) % n; + } + + mai = (s + maio) % n; + } + + return ma ? ma[mai] : mai; +} diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map index 1ff1286..ce55746 100644 --- a/src/gsm/libosmogsm.map +++ b/src/gsm/libosmogsm.map @@ -110,6 +110,7 @@ gsm0502_calc_paging_group; gsm0502_fn_remap; +gsm0502_hop_seq_gen; gsm0503_xcch; gsm0503_rach; -- To view, visit https://gerrit.osmocom.org/c/libosmocore/+/18244 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: libosmocore Gerrit-Branch: master Gerrit-Change-Id: I8aba1578cc9d1bd89d4f5d33a6e8fedc8bea789a Gerrit-Change-Number: 18244 Gerrit-PatchSet: 5 Gerrit-Owner: fixeria <axilirator at gmail.com> Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria <axilirator at gmail.com> Gerrit-Reviewer: laforge <laforge at osmocom.org> Gerrit-Reviewer: tnt <tnt at 246tNt.com> Gerrit-MessageType: merged -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/gerrit-log/attachments/20200515/b72a1fe2/attachment.htm>