diff options
| -rw-r--r-- | openbsc/src/libbsc/arfcn_range_encode.c | 141 |
1 files changed, 83 insertions, 58 deletions
diff --git a/openbsc/src/libbsc/arfcn_range_encode.c b/openbsc/src/libbsc/arfcn_range_encode.c index a047a06ea..1a26523e9 100644 --- a/openbsc/src/libbsc/arfcn_range_encode.c +++ b/openbsc/src/libbsc/arfcn_range_encode.c @@ -176,16 +176,6 @@ int range_enc_determine_range(const int *arfcns, const int size, int *f0) return ARFCN_RANGE_INVALID; } -/* - * The below is easier is to write in four methods than - * to use the max_bits. The encoding is so screwed.. as - * the bits need to be put in place in the wrong order.. - */ -#define HIGH_BITS(w, index, bits, offset) \ - (w[index - 1] >> (bits - offset)) -#define LOW_BITS(w, index, bits, offset) \ - (w[index - 1]) - static void write_orig_arfcn(uint8_t *chan_list, int f0) { chan_list[0] |= (f0 >> 9) & 1; @@ -193,6 +183,88 @@ static void write_orig_arfcn(uint8_t *chan_list, int f0) chan_list[2] = (f0 & 1) << 7; } +static void write_all_wn(uint8_t *chan_list, int bit_offs, + int *w, int w_size, int w1_len) +{ + int octet_offs = 0; /* offset into chan_list */ + int wk_len = w1_len; /* encoding size in bits of w[k] */ + int k; /* 1 based */ + int level = 0; /* tree level, top level = 0 */ + int lvl_left = 1; /* nodes per tree level */ + + /* W(2^i) to W(2^(i+1)-1) are on w1_len-i bits when present */ + + for (k = 1; k <= w_size; k++) { + int wk_left = wk_len; + DEBUGP(DRR, + "k=%d, wk_len=%d, offs=%d:%d, level=%d, " + "lvl_left=%d\n", + k, wk_len, octet_offs, bit_offs, level, lvl_left); + + while (wk_left > 0) { + int cur_bits = 8 - bit_offs; + int cur_mask; + int wk_slice; + + if (cur_bits > wk_left) + cur_bits = wk_left; + + cur_mask = ((1 << cur_bits) - 1); + + DEBUGP(DRR, + " wk_left=%d, cur_bits=%d, offs=%d:%d\n", + wk_left, cur_bits, octet_offs, bit_offs); + + /* advance */ + wk_left -= cur_bits; + bit_offs += cur_bits; + + /* right aligned wk data for current out octet */ + wk_slice = (w[k-1] >> wk_left) & cur_mask; + + /* cur_bits now contains the number of bits + * that are to be copied from wk to the chan_list. + * wk_left is set to the number of bits that must + * not yet be copied. + * bit_offs points after the bit area that is going to + * be overwritten: + * + * wk_left + * | + * v + * wk: WWWWWWWWWWW + * |||||<-- wk_slice, cur_bits=5 + * --WWWWW- + * ^ + * | + * bit_offs + */ + + DEBUGP(DRR, + " wk=%02x, slice=%02x/%02x, cl=%02x\n", + w[k-1], wk_slice, cur_mask, wk_slice << (8 - bit_offs)); + + chan_list[octet_offs] &= ~(cur_mask << (8 - bit_offs)); + chan_list[octet_offs] |= wk_slice << (8 - bit_offs); + + /* adjust output */ + if (bit_offs == 8) { + bit_offs = 0; + octet_offs += 1; + } + } + + /* adjust bit sizes */ + lvl_left -= 1; + if (!lvl_left) { + /* completed tree level, advance to next */ + level += 1; + lvl_left = 1 << level; + wk_len -= 1; + } + } +} + int range_enc_range128(uint8_t *chan_list, int f0, int *w) { chan_list[0] = 0x8C; @@ -213,57 +285,10 @@ int range_enc_range256(uint8_t *chan_list, int f0, int *w) int range_enc_range512(uint8_t *chan_list, int f0, int *w) { - struct gsm48_range_512 *range512; chan_list[0] = 0x88; write_orig_arfcn(chan_list, f0); - range512 = (struct gsm48_range_512 *) &chan_list[0]; - - /* W(1) */ - range512->w1_hi = HIGH_BITS(w, 1, 9, 7); - range512->w1_lo = LOW_BITS (w, 1, 9, 2); - /* W(2) */ - range512->w2_hi = HIGH_BITS(w, 2, 8, 6); - range512->w2_lo = LOW_BITS (w, 2, 8, 2); - /* W(3) */ - range512->w3_hi = HIGH_BITS(w, 3, 8, 6); - range512->w3_lo = LOW_BITS (w, 3, 8, 2); - /* W(4) */ - range512->w4_hi = HIGH_BITS(w, 4, 7, 6); - range512->w4_lo = LOW_BITS (w, 4, 7, 1); - /* W(5) */ - range512->w5 = HIGH_BITS(w, 5, 7, 7); - /* W(6) */ - range512->w6 = HIGH_BITS(w, 6, 7, 7); - /* W(7) */ - range512->w7_hi = HIGH_BITS(w, 7, 7, 1); - range512->w7_lo = LOW_BITS (w, 7, 7, 6); - /* W(8) */ - range512->w8_hi = HIGH_BITS(w, 8, 6, 2); - range512->w8_lo = LOW_BITS (w, 8, 6, 4); - /* W(9) */ - range512->w9_hi = HIGH_BITS(w, 9, 6, 4); - range512->w9_lo = LOW_BITS(w, 9, 6, 2); - /* W(10) */ - range512->w10 = HIGH_BITS(w, 10, 6, 6); - /* W(11) */ - range512->w11 = HIGH_BITS(w, 11, 6, 6); - /* W(12) */ - range512->w12_hi = HIGH_BITS(w, 12, 6, 2); - range512->w12_lo = LOW_BITS (w, 12, 6, 4); - /* W(13) */ - range512->w13_hi = HIGH_BITS(w, 13, 6, 4); - range512->w13_lo = LOW_BITS(w, 13, 6, 2); - /* W(14) */ - range512->w14 = HIGH_BITS(w, 14, 6, 6); - /* W(15) */ - range512->w15 = HIGH_BITS(w, 15, 6, 6); - /* W(16) */ - range512->w16_hi = HIGH_BITS(w, 16, 5, 2); - range512->w16_lo = LOW_BITS(w, 16, 5, 3); - /* W(17) */ - range512->w17 = HIGH_BITS(w, 17, 5, 5); - + write_all_wn(&chan_list[2], 1, w, 17, 9); return 0; } |