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repn passes tests.
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@ -15,40 +15,16 @@
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(x==0) ? 0 : \
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1 + ((x - 1) / y);
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// repn :: Word -> [Word] -> Atom
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// repn bits blox =
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// (bits > 64) & \case
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// True → error "repn only works with block sizes <= 64"
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// False → view (from atomWords)
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// $ VP.fromList
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// $ finish
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// $ foldl' f ([], 0, 0)
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// $ zip (repeat bits) blox
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// where
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// finish (acc, wor, n) = reverse
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// $ dropWhile (==0)
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// $ case n of { 0 -> acc; _ -> wor:acc }
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//
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// slice size off wor = shiftL (takeBits size wor)
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// $ fromIntegral off
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//
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// f (acc, wor, off) (remBlok, blok) =
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// let rem = 64 - off in
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// compare remBlok rem & \case
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// LT -> (acc, res, off+bits)
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// where res = wor .|. slice bits off blok
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// EQ -> (res:acc, 0, 0)
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// where res = (wor .|. slice bits off blok)
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// GT -> f (res:acc, 0, 0) (remBlok', blok')
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// where res = wor .|. slice rem off blok
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// remBlok' = remBlok-rem
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// blok' = shiftR blok (fromIntegral bits)
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/*
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TODO Don't do the double flop.
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*/
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u3_noun u3qc_repn(u3_atom bits, u3_noun blox) {
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if ( !_(u3a_is_cat(bits) || bits==0 || bits>31) ) {
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return u3m_bail(c3__fail);
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}
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blox = u3kb_flop(blox);
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//
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// We need to enforce the invariant that the result does not contain
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// leading (? TODO). Since each input block must be smaller than
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@ -69,11 +45,11 @@ u3_noun u3qc_repn(u3_atom bits, u3_noun blox) {
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if (blok_n != 0) break;
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u3l_log("strip\n");
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blox = u3t(blox);
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}
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blox = u3kb_flop(blox);
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//
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// Calculate input and output size.
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//
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@ -81,8 +57,6 @@ u3_noun u3qc_repn(u3_atom bits, u3_noun blox) {
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c3_w bit_widt = num_blox * bits;
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c3_w wor_widt = DIVCEIL(bit_widt, 32);
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u3l_log("%d*%d=%d [%d]\n", bits, num_blox, bit_widt, wor_widt);
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//
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// Allocate a proto-atom. This is u3a_slab without initialization.
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//
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@ -102,60 +76,54 @@ u3_noun u3qc_repn(u3_atom bits, u3_noun blox) {
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// Bits are pushed into the `acc` register and flushed to the buffer
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// once full.
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//
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// acc register
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// idx where the register will be flushed to
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// use number of register bits filled (used)
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//
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c3_w acc = 0; // Word to write into
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c3_w acc_idx = 0; // Where the word will be written to
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c3_w acc_used = 0; // Number of bits used in acc.
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c3_w acc=0, idx=0, use=0;
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void flush() {
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u3l_log("%d @ %d\n", acc, acc_idx);
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buf[acc_idx++] = acc;
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buf[idx++] = acc;
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acc = 0;
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acc_used = 0;
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use = 0;
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}
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c3_w slice(c3_w sz, c3_w off, c3_w val) {
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u3l_log("slice(%d,%d,%d) = %d\n", sz, off, val, TAKEBITS(sz, val) << off);
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return TAKEBITS(sz, val) << off;
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}
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for (c3_w i=0; i<num_blox; i++) {
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c3_w block = u3a_h(blox);
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c3_w blok = u3a_h(blox);
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blox = u3t(blox);
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u3l_log("#%d = %d\n", i, block);
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for (c3_w rem_in_block=bits; rem_in_block;) {
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c3_w rem_in_acc = 32 - acc_used;
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if (rem_in_block == rem_in_acc) { // EQ
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acc |= slice(rem_in_block, acc_used, block);
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u3l_log("acc:%d\n", acc);
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for (c3_w rem_in_blok=bits; rem_in_blok;) {
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c3_w rem_in_acc = 32 - use;
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if (rem_in_blok == rem_in_acc) { // EQ
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acc |= slice(rem_in_blok, use, blok);
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flush();
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rem_in_block = 0;
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} else if (rem_in_block < rem_in_acc) { // LT
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acc |= slice(rem_in_block, acc_used, block);
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u3l_log("acc:%d\n", acc);
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acc_used += rem_in_block;
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rem_in_block = 0;
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} else { // GT
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acc |= slice(rem_in_acc, acc_used, block);
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u3l_log("acc:%d\n", acc);
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rem_in_block -= rem_in_acc;
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block = block >> rem_in_acc;
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rem_in_blok = 0;
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} else if (rem_in_blok < rem_in_acc) { // LT
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acc |= slice(rem_in_blok, use, blok);
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use += rem_in_blok;
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rem_in_blok = 0;
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} else { // GT
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acc |= slice(rem_in_acc, use, blok);
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rem_in_blok -= rem_in_acc;
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blok = blok >> rem_in_acc;
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flush();
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}
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}
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u3l_log("acc:%d acc_idx:%d acc_used:%d\n", acc, acc_idx, acc_used);
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}
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//
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// If the last word isn't fully used, it will still need to be
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// flushed.
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//
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if (acc_used) flush();
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if (use) flush();
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return u3a_mint(buf, wor_widt);
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return u3a_malt(buf);
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}
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u3_noun u3wc_repn(u3_noun cor) {
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