From b25989e47adfadabcf0dabfd58d615622887cee0 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Sat, 13 Dec 2025 19:16:32 +0100
Subject: Intertwined table seems to work

---
 src/solvers/h48/distribution_h48.h | 78 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 src/solvers/h48/distribution_h48.h

(limited to 'src/solvers/h48/distribution_h48.h')

diff --git a/src/solvers/h48/distribution_h48.h b/src/solvers/h48/distribution_h48.h
new file mode 100644
index 0000000..8b66c06
--- /dev/null
+++ b/src/solvers/h48/distribution_h48.h
@@ -0,0 +1,78 @@
+/*
+This file is very similar to ../distibution.h, but some adaptations are
+needed for H48 because of the intertwined fallback table, and it is easier
+to have some duplication than to make these functions needlessly generic.
+*/
+
+STATIC void *getdistribution_h48_runthread(void *);
+STATIC void getdistribution_h48(const unsigned char *,
+    uint64_t [static INFO_DISTRIBUTION_LEN], const tableinfo_t [static 1]);
+
+STATIC void *
+getdistribution_h48_runthread(void *arg)
+{
+	getdistribution_data_t *data = (getdistribution_data_t *)arg;
+	const unsigned char *table;
+	uint8_t j, k, m;
+	uint64_t line, d;
+	unsigned char t;
+
+	memset(data->distr, 0, INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+
+	k = data->bits;
+	table = data->table;
+	m = TABLE_MASK(0, k);
+	for (line = data->min; line < data->max; line++) {
+		for (d = 0; d < H48_LINE_BYTES; d++) {
+			t = table[d + line * H48_LINE_BYTES];
+			for (j = 0; j < ENTRIES_PER_BYTE(k); j++)
+				data->distr[(t & (m << (j*k))) >> (j*k)]++;
+		}
+		t = table[(line+1) * H48_LINE_BYTES - 1];
+		data->distr[(t & (m << (2*k))) >> (2*k)]--;
+		data->distr[(t & (m << (3*k))) >> (3*k)]--;
+	}
+
+	return NULL;
+}
+
+STATIC void
+getdistribution_h48(
+	const unsigned char *table,
+	uint64_t distr[static INFO_DISTRIBUTION_LEN],
+	const tableinfo_t info[static 1]
+) {
+	getdistribution_data_t targ[THREADS];
+	wrapthread_define_var_thread_t(thread[THREADS]);
+	uint8_t pval, k;
+	uint64_t local_distr[THREADS][INFO_DISTRIBUTION_LEN];
+	uint64_t i, j, lines, lines_per_thread, c, cc;
+
+	k = info->bits;
+	lines = H48_LINES(info->h48h);
+	lines_per_thread = DIV_ROUND_UP(lines, THREADS);
+
+	for (i = 0; i < THREADS; i++) {
+		targ[i] = (getdistribution_data_t) {
+			.min = i * lines_per_thread,
+			.max = MIN((i+1) * lines_per_thread, lines),
+			.bits = k,
+			.distr = local_distr[i],
+			.table = table,
+		};
+		wrapthread_create(&thread[i], NULL,
+		    getdistribution_h48_runthread, &targ[i]);
+	}
+
+	for (i = 0; i < THREADS; i++)
+		wrapthread_join(thread[i], NULL);
+
+	memset(distr, 0, INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+	for (i = 0; i < THREADS; i++)
+		for (j = 0; j < INFO_DISTRIBUTION_LEN; j++)
+			distr[j] += local_distr[i][j];
+
+	/* Clean up excess values */
+	c = H48_LINE_EXT(H48_COORDMAX(info->h48h)) % H48_LINE_ALLCOORDS;
+	distr[3] -= H48_LINE_COORDS - c;
+}
-- 
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