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/// @file
#include "jets/k.h"
#include "jets/q.h"
#include "jets/w.h"
#include "noun.h"
/*
Get the lowest `n` bits of a word `w` using a bitmask.
*/
#define TAKEBITS(n,w) \
((n)==32) ? (w) : \
((n)==0) ? 0 : \
((w) & ((1 << (n)) - 1))
/*
Divide, rounding up.
*/
#define DIVCEIL(x,y) \
(x==0) ? 0 : \
1 + ((x - 1) / y);
static u3_noun
_bit_rep(u3_atom bits, u3_noun blox)
{
if ( (c3n == u3a_is_cat(bits) || bits==0 || bits>31) ) {
return u3m_bail(c3__fail);
}
//
// Calculate input and output size.
//
c3_w num_blox_w = u3qb_lent(blox);
c3_w bit_widt_w = num_blox_w * bits;
c3_w wor_widt_w = DIVCEIL(bit_widt_w, 32);
u3i_slab sab_u;
u3i_slab_bare(&sab_u, 5, wor_widt_w);
//
// Fill the atom buffer with bits from each block.
//
// Bits are pushed into the `acc_w` register and flushed to the buffer
// once full.
//
// acc_w register
// use_w number of register bits filled (used)
// cur_w next buffer word to flush into.
//
{
c3_w acc_w=0, use_w=0, *cur_w=sab_u.buf_w;
# define FLUSH() *cur_w++=acc_w; acc_w=use_w=0
# define SLICE(sz,off,val) TAKEBITS(sz, val) << off
for (c3_w i=0; i<num_blox_w; i++) {
u3_noun blok_n = u3h(blox);
blox = u3t(blox);
if ( c3n == u3a_is_cat(blok_n) ) {
return u3m_bail(c3__fail);
}
c3_w blok_w = blok_n;
for (c3_w rem_in_blok_w=bits; rem_in_blok_w;) {
c3_w rem_in_acc_w = 32 - use_w;
if (rem_in_blok_w == rem_in_acc_w) { // EQ
acc_w |= SLICE(rem_in_blok_w, use_w, blok_w);
FLUSH();
rem_in_blok_w = 0;
}
else if (rem_in_blok_w < rem_in_acc_w) { // LT
acc_w |= SLICE(rem_in_blok_w, use_w, blok_w);
use_w += rem_in_blok_w;
rem_in_blok_w = 0;
}
else { // GT
acc_w |= SLICE(rem_in_acc_w, use_w, blok_w);
rem_in_blok_w -= rem_in_acc_w;
blok_w = blok_w >> rem_in_acc_w;
FLUSH();
}
}
}
//
// If the last word isn't fully used, it will still need to be
// flushed.
//
if (use_w) {
FLUSH();
}
}
return u3i_slab_mint(&sab_u);
}
static u3_noun
_block_rep(u3_atom a,
u3_noun b)
{
if ( !_(u3a_is_cat(a)) || (a >= 32) ) {
return u3m_bail(c3__fail);
}
else {
c3_g a_g = a;
c3_w tot_w = 0;
u3i_slab sab_u;
/* Measure and validate the slab required.
*/
{
u3_noun cab = b;
while ( 1 ) {
u3_noun h_cab;
c3_w len_w;
if ( 0 == cab ) {
break;
}
else if ( c3n == u3du(cab) ) {
return u3m_bail(c3__exit);
}
else if ( c3n == u3ud(h_cab = u3h(cab)) ) {
return u3m_bail(c3__exit);
}
else if ( (tot_w + (len_w = u3r_met(a_g, h_cab))) < tot_w ) {
return u3m_bail(c3__fail);
}
tot_w++;
cab = u3t(cab);
}
if ( 0 == tot_w ) {
return 0;
}
u3i_slab_init(&sab_u, a_g, tot_w);
}
/* Chop the list atoms in.
*/
{
u3_noun cab = b;
c3_w pos_w = 0;
while ( 0 != cab ) {
u3_noun h_cab = u3h(cab);
u3r_chop(a_g, 0, 1, pos_w, sab_u.buf_w, h_cab);
pos_w++;
cab = u3t(cab);
}
}
return u3i_slab_mint(&sab_u);
}
}
u3_noun
u3qc_rep(u3_atom a,
u3_atom b,
u3_noun c)
{
if ( 1 == b ) {
return _block_rep(a, c);
}
if ( 0 == a ) {
return _bit_rep(b, c);
}
u3l_log("rep: stub");
return u3_none;
}
u3_noun
u3wc_rep(u3_noun cor)
{
u3_atom bloq, step;
u3_noun a, b;
u3x_mean(cor, u3x_sam_2, &a,
u3x_sam_3, &b, 0);
u3x_bite(a, &bloq, &step);
return u3qc_rep(bloq, step, b);
}
u3_noun
u3kc_rep(u3_atom a,
u3_atom b,
u3_noun c)
{
u3_noun res = u3qc_rep(a, b, c);
u3z(a); u3z(b); u3z(c);
return res;
}
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