crypto: lib - Move mpi into lib/crypto

[thirdparty/linux.git] / lib / crypto / mpi / mpi-inline.h

diff --git a/lib/crypto/mpi/mpi-inline.h b/lib/crypto/mpi/mpi-inline.h
new file mode 100644 (file)
index 0000000..980b6b9
--- /dev/null
+++ b/lib/crypto/mpi/mpi-inline.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* mpi-inline.h  -  Internal to the Multi Precision Integers
+ *     Copyright (C) 1994, 1996, 1998, 1999 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * Note: This code is heavily based on the GNU MP Library.
+ *      Actually it's the same code with only minor changes in the
+ *      way the data is stored; this is to support the abstraction
+ *      of an optional secure memory allocation which may be used
+ *      to avoid revealing of sensitive data due to paging etc.
+ *      The GNU MP Library itself is published under the LGPL;
+ *      however I decided to publish this code under the plain GPL.
+ */
+
+#ifndef G10_MPI_INLINE_H
+#define G10_MPI_INLINE_H
+
+#ifndef G10_MPI_INLINE_DECL
+#define G10_MPI_INLINE_DECL  static inline
+#endif
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+             mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+       mpi_limb_t x;
+
+       x = *s1_ptr++;
+       s2_limb += x;
+       *res_ptr++ = s2_limb;
+       if (s2_limb < x) {      /* sum is less than the left operand: handle carry */
+               while (--s1_size) {
+                       x = *s1_ptr++ + 1;      /* add carry */
+                       *res_ptr++ = x; /* and store */
+                       if (x)  /* not 0 (no overflow): we can stop */
+                               goto leave;
+               }
+               return 1;       /* return carry (size of s1 to small) */
+       }
+
+leave:
+       if (res_ptr != s1_ptr) {        /* not the same variable */
+               mpi_size_t i;   /* copy the rest */
+               for (i = 0; i < s1_size - 1; i++)
+                       res_ptr[i] = s1_ptr[i];
+       }
+       return 0;               /* no carry */
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+           mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+       mpi_limb_t cy = 0;
+
+       if (s2_size)
+               cy = mpihelp_add_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+       if (s1_size - s2_size)
+               cy = mpihelp_add_1(res_ptr + s2_size, s1_ptr + s2_size,
+                                  s1_size - s2_size, cy);
+       return cy;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+             mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+       mpi_limb_t x;
+
+       x = *s1_ptr++;
+       s2_limb = x - s2_limb;
+       *res_ptr++ = s2_limb;
+       if (s2_limb > x) {
+               while (--s1_size) {
+                       x = *s1_ptr++;
+                       *res_ptr++ = x - 1;
+                       if (x)
+                               goto leave;
+               }
+               return 1;
+       }
+
+leave:
+       if (res_ptr != s1_ptr) {
+               mpi_size_t i;
+               for (i = 0; i < s1_size - 1; i++)
+                       res_ptr[i] = s1_ptr[i];
+       }
+       return 0;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+           mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+       mpi_limb_t cy = 0;
+
+       if (s2_size)
+               cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+       if (s1_size - s2_size)
+               cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
+                                  s1_size - s2_size, cy);
+       return cy;
+}
+
+#endif /*G10_MPI_INLINE_H */