diff options
| -rw-r--r-- | lib/libcrypto/bn/bn_internal.h | 115 |
1 files changed, 114 insertions, 1 deletions
diff --git a/lib/libcrypto/bn/bn_internal.h b/lib/libcrypto/bn/bn_internal.h index 003d8cac2d3..ab3efd14f46 100644 --- a/lib/libcrypto/bn/bn_internal.h +++ b/lib/libcrypto/bn/bn_internal.h @@ -1,4 +1,4 @@ -/* $OpenBSD: bn_internal.h,v 1.2 2023/02/14 17:58:26 jsing Exp $ */ +/* $OpenBSD: bn_internal.h,v 1.3 2023/02/14 18:31:02 jsing Exp $ */ /* * Copyright (c) 2023 Joel Sing <jsing@openbsd.org> * @@ -54,6 +54,54 @@ bn_ct_eq_zero_mask(BN_ULONG w) } #endif +/* + * Big number primitives are named as the operation followed by a suffix + * that indicates the number of words that it operates on, where 'w' means + * single word, 'dw' means double word, 'tw' means triple word and 'qw' means + * quadruple word. Unless otherwise noted, the size of the output is implied + * based on its inputs, for example bn_mulw() takes two single word inputs + * and is going to produce a double word result. + * + * Where a function implements multiple operations, these are listed in order. + * For example, a function that computes (r1:r0) = a * b + c is named + * bn_mulw_addw(), producing a double word result. + */ + +/* + * bn_addw() computes (r1:r0) = a + b, where both inputs are single words, + * producing a double word result. The value of r1 is the carry from the + * addition. + */ +#ifndef HAVE_BN_ADDW +#ifdef BN_LLONG +static inline void +bn_addw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_r1, BN_ULONG *out_r0) +{ + BN_ULLONG r; + + r = (BN_ULLONG)a + (BN_ULLONG)b; + + *out_r1 = r >> BN_BITS2; + *out_r0 = r & BN_MASK2; +} +#else + +static inline void +bn_addw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_r1, BN_ULONG *out_r0) +{ + BN_ULONG r1, r0, c1, c2; + + c1 = a | b; + c2 = a & b; + r0 = a + b; + r1 = ((c1 & ~r0) | c2) >> (BN_BITS2 - 1); /* carry */ + + *out_r1 = r1; + *out_r0 = r0; +} +#endif +#endif + #ifndef HAVE_BN_UMUL_HILO #ifdef BN_LLONG static inline void @@ -188,4 +236,69 @@ bn_umul_hi(BN_ULONG a, BN_ULONG b) } #endif +/* + * bn_mulw_addw() computes (r1:r0) = a * b + c with all inputs being single + * words, producing a double word result. + */ +#ifndef HAVE_BN_MULW_ADDW +static inline void +bn_mulw_addw(BN_ULONG a, BN_ULONG b, BN_ULONG c, BN_ULONG *out_r1, + BN_ULONG *out_r0) +{ + BN_ULONG carry, r1, r0; + + bn_umul_hilo(a, b, &r1, &r0); + bn_addw(r0, c, &carry, &r0); + r1 += carry; + + *out_r1 = r1; + *out_r0 = r0; +} +#endif + +/* + * bn_mulw_addw_addw() computes (r1:r0) = a * b + c + d with all inputs being + * single words, producing a double word result. + */ +#ifndef HAVE_BN_MULW_ADDW_ADDW +static inline void +bn_mulw_addw_addw(BN_ULONG a, BN_ULONG b, BN_ULONG c, BN_ULONG d, + BN_ULONG *out_r1, BN_ULONG *out_r0) +{ + BN_ULONG carry, r1, r0; + + bn_mulw_addw(a, b, c, &r1, &r0); + bn_addw(r0, d, &carry, &r0); + r1 += carry; + + *out_r1 = r1; + *out_r0 = r0; +} +#endif + +/* + * bn_mulw_addtw() computes (r2:r1:r0) = a * b + (c2:c1:c0), where a and b are + * single words and (c2:c1:c0) is a triple word, producing a triple word result. + * The caller must ensure that the inputs provided do not result in c2 + * overflowing. + */ +#ifndef HAVE_BN_MULW_ADDTW +static inline void +bn_mulw_addtw(BN_ULONG a, BN_ULONG b, BN_ULONG c2, BN_ULONG c1, BN_ULONG c0, + BN_ULONG *out_r2, BN_ULONG *out_r1, BN_ULONG *out_r0) +{ + BN_ULONG carry, r2, r1, r0, x1, x0; + + bn_umul_hilo(a, b, &x1, &x0); + bn_addw(c0, x0, &carry, &r0); + x1 += carry; + bn_addw(c1, x1, &carry, &r1); + r2 = c2 + carry; + + *out_r2 = r2; + *out_r1 = r1; + *out_r0 = r0; +} +#endif + #endif |