From 10b9bb95111b90ec08dc4182341b5cc6c9065b22 Mon Sep 17 00:00:00 2001
From: d_m <d_m@plastic-idolatry.com>
Date: Thu, 9 Nov 2023 21:51:44 -0500
Subject: [PATCH] add more bc15 functions

---
 src/bcb.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 src/bcb.h |  4 ++++
 2 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/src/bcb.c b/src/bcb.c
index 822b8df..ee84398 100644
--- a/src/bcb.c
+++ b/src/bcb.c
@@ -142,18 +142,73 @@ bc15int(bc15 t)
 	return acc;
 }
 
+bc3
+bc15sign(bc15 a)
+{
+	int i;
+	for(i = 28; i >= 0; i -= 2) {
+		bc3 x = (a >> i) & 0x3;
+		if (x != 0) return x;
+	}
+	return 0;
+}
+
+bc15
+bc15tnand(bc15 a, bc15 b)
+{
+	bc15 acc = 0;
+	int i;
+	for(i = 0; i < 30; i += 2) {
+		int x = (a >> i) & 0x3;
+		int y = (b >> i) & 0x3;
+		int digit = x == y ? (4 - x) & 0x3 : (x | y) >> 1;
+		acc |= (digit << i);
+	}
+	return acc;
+}
+
+bc15
+bc15tnor(bc15 a, bc15 b)
+{
+	bc15 acc = 0;
+	int i, digit;
+	for(i = 0; i < 30; i += 2) {
+		int x = (a >> i) & 0x3;
+		int y = (b >> i) & 0x3;
+		if (x == y) {
+			digit = (4 - x) & 0x3;
+		} else {
+			int t = ((x ^ y) + 1) & 0x3;
+			digit = t | (t>>1);
+		}
+		acc |= (digit << i);
+	}
+	return acc;
+}
+
+bc15
+bc15negate(bc15 a)
+{
+	bc15 acc = 0;
+	for(int i = 0; i < 30; i += 2) {
+		int x = (a >> i) & 0x3;
+		int nx = (4 - digit) & 0x3;
+		acc |= (nx << i);
+	}
+	return acc;
+}
+
 bc15
 bc15add(bc15 a, bc15 b)
 {
 	bc15 acc = 0;
 	int i, carry = 0;
-	for(i = 0; i < 30 && (carry != 0 || (a >> i) != 0 || (b >> i) != 0); i += 2) {
+	for(i = 0; i < 30; i += 2) {
 		int digit = carry;
 		carry = 0;
 		bc15carry((a >> i) & 0x3, &digit, &carry);
 		bc15carry((b >> i) & 0x3, &digit, &carry);
 		acc |= (digit << i);
-		;
 	}
 	return acc;
 }
diff --git a/src/bcb.h b/src/bcb.h
index 0360985..fea1b32 100644
--- a/src/bcb.h
+++ b/src/bcb.h
@@ -47,6 +47,10 @@ void pbc3(bc3 t);
 // 15 Trits
 bc15 intbc15(int n);
 int bc15int(bc15 t);
+bc3 bc15sign(bc15 a);
+bc15 bc15tnand(bc15 a);
+bc15 bc15tnor(bc15 a);
+bc15 bc15negate(bc15 a);
 bc15 bc15add(bc15 a, bc15 b);
 void bc15carry(int sum, int *digit, int *carry);
 
-- 
2.45.2