X-Git-Url: https://git.cryptolib.org/?p=avr-crypto-lib.git;a=blobdiff_plain;f=bigint%2Fbigint.c;h=c69d42ec7d22d389b67324deebc92c7ea443aa86;hp=6db0389d693490bdc818b4688e88b29370c6e4f7;hb=cc6b183296a5852449e3324737e2a2dece788786;hpb=06d9213f132d05f61b65acc51de6f7ad1b42f48a

diff --git a/bigint/bigint.c b/bigint/bigint.c
index 6db0389..c69d42e 100644
--- a/bigint/bigint.c
+++ b/bigint/bigint.c
@@ -291,26 +291,34 @@ int8_t bigint_cmp_u(const bigint_t* a, const bigint_t* b){
 
 void bigint_add_s(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	uint8_t s;
+	int8_t d = 0;
 	s  = GET_SIGN(a)?2:0;
 	s |= GET_SIGN(b)?1:0;
 	switch(s){
 		case 0: /* both positive */
+			d = 1;
 			bigint_add_u(dest, a,b);
-			SET_POS(dest);
 			break;
 		case 1: /* a positive, b negative */
+			d = bigint_cmp_u(a,b);
 			bigint_sub_u(dest, a, b);
 			break;
 		case 2: /* a negative, b positive */
+			d = bigint_cmp_u(b,a);
 			bigint_sub_u(dest, b, a);
 			break;
 		case 3: /* both negative */
+			d = -1;
 			bigint_add_u(dest, a, b);
-			SET_NEG(dest);
 			break;
 		default: /* how can this happen?*/
 			break;
 	}
+	if(d<0){
+		SET_NEG(dest);
+	}else{
+		SET_POS(dest);
+	}
 }
 
 /******************************************************************************/