Provide and use various quad word primitives.

This includes bn_qwaddqw(), bn_qwsubqw(), bn_qwmulw_addw() and
bn_qwmulw_addqw_addw(). These can typically be optimised on architectures
that have a reasonable number of general purpose registers.

ok tb@

3 files changed, 120 insertions, 27 deletions

diff --git a/src/lib/libcrypto/bn/bn_add.c b/src/lib/libcrypto/bn/bn_add.c
index 92489b7da3..36f160ab5f 100644
--- a/src/lib/libcrypto/bn/bn_add.c
+++ b/src/lib/libcrypto/bn/bn_add.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_add.c,v 1.24 2023/02/22 05:46:37 jsing Exp $ */
+/* $OpenBSD: bn_add.c,v 1.25 2023/06/12 16:17:24 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -80,18 +80,14 @@ bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, int n)
         if (n <= 0)
                 return 0;
 
-#ifndef OPENSSL_SMALL_FOOTPRINT
         while (n & ~3) {
-                bn_addw_addw(a[0], b[0], carry, &carry, &r[0]);
-                bn_addw_addw(a[1], b[1], carry, &carry, &r[1]);
-                bn_addw_addw(a[2], b[2], carry, &carry, &r[2]);
-                bn_addw_addw(a[3], b[3], carry, &carry, &r[3]);
+                bn_qwaddqw(a[3], a[2], a[1], a[0], b[3], b[2], b[1], b[0],
+                    carry, &carry, &r[3], &r[2], &r[1], &r[0]);
                 a += 4;
                 b += 4;
                 r += 4;
                 n -= 4;
         }
-#endif
         while (n) {
                 bn_addw_addw(a[0], b[0], carry, &carry, &r[0]);
                 a++;
@@ -165,18 +161,14 @@ bn_sub_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, int n)
         if (n <= 0)
                 return 0;
 
-#ifndef OPENSSL_SMALL_FOOTPRINT
         while (n & ~3) {
-                bn_subw_subw(a[0], b[0], borrow, &borrow, &r[0]);
-                bn_subw_subw(a[1], b[1], borrow, &borrow, &r[1]);
-                bn_subw_subw(a[2], b[2], borrow, &borrow, &r[2]);
-                bn_subw_subw(a[3], b[3], borrow, &borrow, &r[3]);
+                bn_qwsubqw(a[3], a[2], a[1], a[0], b[3], b[2], b[1], b[0],
+                    borrow, &borrow, &r[3], &r[2], &r[1], &r[0]);
                 a += 4;
                 b += 4;
                 r += 4;
                 n -= 4;
         }
-#endif
         while (n) {
                 bn_subw_subw(a[0], b[0], borrow, &borrow, &r[0]);
                 a++;
diff --git a/src/lib/libcrypto/bn/bn_internal.h b/src/lib/libcrypto/bn/bn_internal.h
index 8a729b8e44..5f86e21330 100644
--- a/src/lib/libcrypto/bn/bn_internal.h
+++ b/src/lib/libcrypto/bn/bn_internal.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bn_internal.h,v 1.11 2023/03/07 09:35:55 jsing Exp $ */
+/*      $OpenBSD: bn_internal.h,v 1.12 2023/06/12 16:17:24 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -123,6 +123,33 @@ bn_addw_addw(BN_ULONG a, BN_ULONG b, BN_ULONG c, BN_ULONG *out_r1,
 #endif
 
 /*
+ * bn_qwaddqw() computes
+ * (r4:r3:r2:r1:r0) = (a3:a2:a1:a0) + (b3:b2:b1:b0) + carry, where a is a quad word,
+ * b is a quad word, and carry is a single word with value 0 or 1, producing a four
+ * word result and carry.
+ */
+#ifndef HAVE_BN_QWADDQW
+static inline void
+bn_qwaddqw(BN_ULONG a3, BN_ULONG a2, BN_ULONG a1, BN_ULONG a0, BN_ULONG b3,
+    BN_ULONG b2, BN_ULONG b1, BN_ULONG b0, BN_ULONG carry, BN_ULONG *out_carry,
+    BN_ULONG *out_r3, BN_ULONG *out_r2, BN_ULONG *out_r1, BN_ULONG *out_r0)
+{
+        BN_ULONG r3, r2, r1, r0;
+
+        bn_addw_addw(a0, b0, carry, &carry, &r0);
+        bn_addw_addw(a1, b1, carry, &carry, &r1);
+        bn_addw_addw(a2, b2, carry, &carry, &r2);
+        bn_addw_addw(a3, b3, carry, &carry, &r3);
+
+        *out_carry = carry;
+        *out_r3 = r3;
+        *out_r2 = r2;
+        *out_r1 = r1;
+        *out_r0 = r0;
+}
+#endif
+
+/*
  * bn_subw() computes r0 = a - b, where both inputs are single words,
  * producing a single word result and borrow.
  */
@@ -160,6 +187,33 @@ bn_subw_subw(BN_ULONG a, BN_ULONG b, BN_ULONG c, BN_ULONG *out_borrow,
 #endif
 
 /*
+ * bn_qwsubqw() computes
+ * (r3:r2:r1:r0) = (a3:a2:a1:a0) - (b3:b2:b1:b0) - borrow, where a is a quad word,
+ * b is a quad word, and borrow is a single word with value 0 or 1, producing a
+ * four word result and borrow.
+ */
+#ifndef HAVE_BN_QWSUBQW
+static inline void
+bn_qwsubqw(BN_ULONG a3, BN_ULONG a2, BN_ULONG a1, BN_ULONG a0, BN_ULONG b3,
+    BN_ULONG b2, BN_ULONG b1, BN_ULONG b0, BN_ULONG borrow, BN_ULONG *out_borrow,
+    BN_ULONG *out_r3, BN_ULONG *out_r2, BN_ULONG *out_r1, BN_ULONG *out_r0)
+{
+        BN_ULONG r3, r2, r1, r0;
+
+        bn_subw_subw(a0, b0, borrow, &borrow, &r0);
+        bn_subw_subw(a1, b1, borrow, &borrow, &r1);
+        bn_subw_subw(a2, b2, borrow, &borrow, &r2);
+        bn_subw_subw(a3, b3, borrow, &borrow, &r3);
+
+        *out_borrow = borrow;
+        *out_r3 = r3;
+        *out_r2 = r2;
+        *out_r1 = r1;
+        *out_r0 = r0;
+}
+#endif
+
+/*
  * bn_mulw() computes (r1:r0) = a * b, where both inputs are single words,
  * producing a double word result.
  */
@@ -387,4 +441,58 @@ bn_mul2_mulw_addtw(BN_ULONG a, BN_ULONG b, BN_ULONG c2, BN_ULONG c1, BN_ULONG c0
 }
 #endif
 
+/*
+ * bn_qwmulw_addw() computes (r4:r3:r2:r1:r0) = (a3:a2:a1:a0) * b + c, where a
+ * is a quad word, b is a single word and c is a single word, producing a five
+ * word result.
+ */
+#ifndef HAVE_BN_QWMULW_ADDW
+static inline void
+bn_qwmulw_addw(BN_ULONG a3, BN_ULONG a2, BN_ULONG a1, BN_ULONG a0, BN_ULONG b,
+    BN_ULONG c, BN_ULONG *out_r4, BN_ULONG *out_r3, BN_ULONG *out_r2,
+    BN_ULONG *out_r1, BN_ULONG *out_r0)
+{
+        BN_ULONG r3, r2, r1, r0;
+
+        bn_mulw_addw(a0, b, c, &c, &r0);
+        bn_mulw_addw(a1, b, c, &c, &r1);
+        bn_mulw_addw(a2, b, c, &c, &r2);
+        bn_mulw_addw(a3, b, c, &c, &r3);
+
+        *out_r4 = c;
+        *out_r3 = r3;
+        *out_r2 = r2;
+        *out_r1 = r1;
+        *out_r0 = r0;
+}
+#endif
+
+/*
+ * bn_qwmulw_addqw_addw() computes
+ * (r4:r3:r2:r1:r0) = (a3:a2:a1:a0) * b + (c3:c2:c1:c0) + d, where a
+ * is a quad word, b is a single word, c is a quad word, and d is a single word,
+ * producing a five word result.
+ */
+#ifndef HAVE_BN_QWMULW_ADDQW_ADDW
+static inline void
+bn_qwmulw_addqw_addw(BN_ULONG a3, BN_ULONG a2, BN_ULONG a1, BN_ULONG a0,
+    BN_ULONG b, BN_ULONG c3, BN_ULONG c2, BN_ULONG c1, BN_ULONG c0, BN_ULONG d,
+    BN_ULONG *out_r4, BN_ULONG *out_r3, BN_ULONG *out_r2, BN_ULONG *out_r1,
+    BN_ULONG *out_r0)
+{
+        BN_ULONG r3, r2, r1, r0;
+
+        bn_mulw_addw_addw(a0, b, c0, d, &d, &r0);
+        bn_mulw_addw_addw(a1, b, c1, d, &d, &r1);
+        bn_mulw_addw_addw(a2, b, c2, d, &d, &r2);
+        bn_mulw_addw_addw(a3, b, c3, d, &d, &r3);
+
+        *out_r4 = d;
+        *out_r3 = r3;
+        *out_r2 = r2;
+        *out_r1 = r1;
+        *out_r0 = r0;
+}
+#endif
+
 #endif
diff --git a/src/lib/libcrypto/bn/bn_mul.c b/src/lib/libcrypto/bn/bn_mul.c
index 118e8cddc5..65088cc5c4 100644
--- a/src/lib/libcrypto/bn/bn_mul.c
+++ b/src/lib/libcrypto/bn/bn_mul.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_mul.c,v 1.37 2023/04/19 10:51:22 jsing Exp $ */
+/* $OpenBSD: bn_mul.c,v 1.38 2023/06/12 16:17:24 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -210,17 +210,13 @@ bn_mul_words(BN_ULONG *r, const BN_ULONG *a, int num, BN_ULONG w)
         if (num <= 0)
                 return 0;
 
-#ifndef OPENSSL_SMALL_FOOTPRINT
         while (num & ~3) {
-                bn_mulw_addw(a[0], w, carry, &carry, &r[0]);
-                bn_mulw_addw(a[1], w, carry, &carry, &r[1]);
-                bn_mulw_addw(a[2], w, carry, &carry, &r[2]);
-                bn_mulw_addw(a[3], w, carry, &carry, &r[3]);
+                bn_qwmulw_addw(a[3], a[2], a[1], a[0], w, carry, &carry,
+                    &r[3], &r[2], &r[1], &r[0]);
                 a += 4;
                 r += 4;
                 num -= 4;
         }
-#endif
         while (num) {
                 bn_mulw_addw(a[0], w, carry, &carry, &r[0]);
                 a++;
@@ -247,17 +243,14 @@ bn_mul_add_words(BN_ULONG *r, const BN_ULONG *a, int num, BN_ULONG w)
         if (num <= 0)
                 return 0;
 
-#ifndef OPENSSL_SMALL_FOOTPRINT
         while (num & ~3) {
-                bn_mulw_addw_addw(a[0], w, r[0], carry, &carry, &r[0]);
-                bn_mulw_addw_addw(a[1], w, r[1], carry, &carry, &r[1]);
-                bn_mulw_addw_addw(a[2], w, r[2], carry, &carry, &r[2]);
-                bn_mulw_addw_addw(a[3], w, r[3], carry, &carry, &r[3]);
+                bn_qwmulw_addqw_addw(a[3], a[2], a[1], a[0], w,
+                    r[3], r[2], r[1], r[0], carry, &carry,
+                    &r[3], &r[2], &r[1], &r[0]);
                 a += 4;
                 r += 4;
                 num -= 4;
         }
-#endif
         while (num) {
                 bn_mulw_addw_addw(a[0], w, r[0], carry, &carry, &r[0]);
                 a++;