diff --git a/include/types.h b/include/types.h index 6baccdbbb..3c5248502 100644 --- a/include/types.h +++ b/include/types.h @@ -1,146 +1,155 @@ /* types.h - some common typedefs * Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc. * * This file is part of GNUPG. * * GNUPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GNUPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #ifndef G10_TYPES_H #define G10_TYPES_H #ifdef HAVE_INTTYPES_H # include /* For uint64_t */ #endif /* The AC_CHECK_SIZEOF() in configure fails for some machines. * we provide some fallback values here */ #if !SIZEOF_UNSIGNED_SHORT # undef SIZEOF_UNSIGNED_SHORT # define SIZEOF_UNSIGNED_SHORT 2 #endif #if !SIZEOF_UNSIGNED_INT # undef SIZEOF_UNSIGNED_INT # define SIZEOF_UNSIGNED_INT 4 #endif #if !SIZEOF_UNSIGNED_LONG # undef SIZEOF_UNSIGNED_LONG # define SIZEOF_UNSIGNED_LONG 4 #endif #include #ifndef HAVE_BYTE_TYPEDEF # undef byte /* maybe there is a macro with this name */ # ifndef __riscos__ typedef unsigned char byte; # else /* Norcroft treats char = unsigned char as legal assignment but char* = unsigned char* as illegal assignment and the same applies to the signed variants as well */ typedef char byte; # endif # define HAVE_BYTE_TYPEDEF #endif #ifndef HAVE_USHORT_TYPEDEF # undef ushort /* maybe there is a macro with this name */ typedef unsigned short ushort; # define HAVE_USHORT_TYPEDEF #endif #ifndef HAVE_ULONG_TYPEDEF # undef ulong /* maybe there is a macro with this name */ typedef unsigned long ulong; # define HAVE_ULONG_TYPEDEF #endif #ifndef HAVE_U16_TYPEDEF # undef u16 /* maybe there is a macro with this name */ # if SIZEOF_UNSIGNED_INT == 2 typedef unsigned int u16; # elif SIZEOF_UNSIGNED_SHORT == 2 typedef unsigned short u16; # else # error no typedef for u16 # endif # define HAVE_U16_TYPEDEF #endif #ifndef HAVE_U32_TYPEDEF # undef u32 /* maybe there is a macro with this name */ # if SIZEOF_UNSIGNED_INT == 4 typedef unsigned int u32; # elif SIZEOF_UNSIGNED_LONG == 4 typedef unsigned long u32; # else # error no typedef for u32 # endif # define HAVE_U32_TYPEDEF #endif /**************** * Warning: Some systems segfault when this u64 typedef and * the dummy code in cipher/md.c is not available. Examples are * Solaris and IRIX. */ #ifndef HAVE_U64_TYPEDEF # undef u64 /* maybe there is a macro with this name */ # if SIZEOF_UINT64_T == 8 typedef uint64_t u64; # ifdef UINT64_C # define U64_C(c) (UINT64_C(c)) # else /* make a best guess, could happen with UNIX98 */ # define U64_C(c) (c) # endif # define HAVE_U64_TYPEDEF #elif SIZEOF_UNSIGNED_INT == 8 typedef unsigned int u64; # define U64_C(c) (c ## U) # define HAVE_U64_TYPEDEF # elif SIZEOF_UNSIGNED_LONG == 8 typedef unsigned long u64; # define U64_C(c) (c ## UL) # define HAVE_U64_TYPEDEF #elif SIZEOF_UNSIGNED_LONG_LONG == 8 typedef unsigned long long u64; # define U64_C(c) (c ## ULL) # define HAVE_U64_TYPEDEF # endif #endif typedef union { int a; short b; char c[1]; long d; #ifdef HAVE_U64_TYPEDEF u64 e; #endif float f; double g; } PROPERLY_ALIGNED_TYPE; struct string_list { struct string_list *next; unsigned int flags; char d[1]; }; typedef struct string_list *STRLIST; typedef struct string_list *strlist_t; + + +#if __GNUC__ > 2 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 5 ) +# define GNUPG_GCC_ATTR_UNUSED __attribute__ ((unused)) +#else +# define GNUPG_GCC_ATTR_UNUSED +#endif + + #endif /*G10_TYPES_H*/ diff --git a/mpi/mpi-internal.h b/mpi/mpi-internal.h index 46da08d0d..9f79781f4 100644 --- a/mpi/mpi-internal.h +++ b/mpi/mpi-internal.h @@ -1,290 +1,291 @@ /* mpi-internal.h - Internal to the Multi Precision Integers * Copyright (C) 1994, 1996 Free Software Foundation, Inc. * Copyright (C) 1998, 2000 Free Software Foundation, Inc. * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GnuPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * 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_INTERNAL_H #define G10_MPI_INTERNAL_H #include "mpi.h" #include "mpi-asm-defs.h" #if BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_INT typedef unsigned int mpi_limb_t; typedef signed int mpi_limb_signed_t; #elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_LONG typedef unsigned long int mpi_limb_t; typedef signed long int mpi_limb_signed_t; #elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_LONG_LONG typedef unsigned long long int mpi_limb_t; typedef signed long long int mpi_limb_signed_t; #elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_SHORT typedef unsigned short int mpi_limb_t; typedef signed short int mpi_limb_signed_t; #else #error BYTES_PER_MPI_LIMB does not match any C type #endif #define BITS_PER_MPI_LIMB (8*BYTES_PER_MPI_LIMB) struct gcry_mpi { int alloced; /* array size (# of allocated limbs) */ int nlimbs; /* number of valid limbs */ unsigned int nbits; /* the real number of valid bits (info only) */ int sign; /* indicates a negative number */ unsigned flags; /* bit 0: array must be allocated in secure memory space */ /* bit 1: not used */ /* bit 2: the limb is a pointer to some xmalloced data */ mpi_limb_t *d; /* array with the limbs */ }; /* If KARATSUBA_THRESHOLD is not already defined, define it to a * value which is good on most machines. */ /* tested 4, 16, 32 and 64, where 16 gave the best performance when * checking a 768 and a 1024 bit ElGamal signature. * (wk 22.12.97) */ #ifndef KARATSUBA_THRESHOLD #define KARATSUBA_THRESHOLD 16 #endif /* The code can't handle KARATSUBA_THRESHOLD smaller than 2. */ #if KARATSUBA_THRESHOLD < 2 #undef KARATSUBA_THRESHOLD #define KARATSUBA_THRESHOLD 2 #endif typedef mpi_limb_t *mpi_ptr_t; /* pointer to a limb */ typedef int mpi_size_t; /* (must be a signed type) */ #define ABS(x) (x >= 0 ? x : -x) #define MIN(l,o) ((l) < (o) ? (l) : (o)) #define MAX(h,i) ((h) > (i) ? (h) : (i)) #define RESIZE_IF_NEEDED(a,b) \ do { \ if( (a)->alloced < (b) ) \ mpi_resize((a), (b)); \ } while(0) /* Copy N limbs from S to D. */ #define MPN_COPY( d, s, n) \ do { \ mpi_size_t _i; \ for( _i = 0; _i < (n); _i++ ) \ (d)[_i] = (s)[_i]; \ } while(0) #define MPN_COPY_INCR( d, s, n) \ do { \ mpi_size_t _i; \ for( _i = 0; _i < (n); _i++ ) \ (d)[_i] = (s)[_i]; \ } while (0) #define MPN_COPY_DECR( d, s, n ) \ do { \ mpi_size_t _i; \ for( _i = (n)-1; _i >= 0; _i--) \ (d)[_i] = (s)[_i]; \ } while(0) /* Zero N limbs at D */ #define MPN_ZERO(d, n) \ do { \ int _i; \ for( _i = 0; _i < (n); _i++ ) \ (d)[_i] = 0; \ } while (0) #define MPN_NORMALIZE(d, n) \ do { \ while( (n) > 0 ) { \ if( (d)[(n)-1] ) \ break; \ (n)--; \ } \ } while(0) #define MPN_NORMALIZE_NOT_ZERO(d, n) \ do { \ for(;;) { \ if( (d)[(n)-1] ) \ break; \ (n)--; \ } \ } while(0) #define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace) \ do { \ if( (size) < KARATSUBA_THRESHOLD ) \ mul_n_basecase (prodp, up, vp, size); \ else \ mul_n (prodp, up, vp, size, tspace); \ } while (0); /* Divide the two-limb number in (NH,,NL) by D, with DI being the largest * limb not larger than (2**(2*BITS_PER_MP_LIMB))/D - (2**BITS_PER_MP_LIMB). * If this would yield overflow, DI should be the largest possible number * (i.e., only ones). For correct operation, the most significant bit of D * has to be set. Put the quotient in Q and the remainder in R. */ #define UDIV_QRNND_PREINV(q, r, nh, nl, d, di) \ do { \ - mpi_limb_t _q, _ql, _r; \ + mpi_limb_t _ql GNUPG_GCC_ATTR_UNUSED; \ + mpi_limb_t _q, _r; \ mpi_limb_t _xh, _xl; \ umul_ppmm (_q, _ql, (nh), (di)); \ _q += (nh); /* DI is 2**BITS_PER_MPI_LIMB too small */ \ umul_ppmm (_xh, _xl, _q, (d)); \ sub_ddmmss (_xh, _r, (nh), (nl), _xh, _xl); \ if( _xh ) { \ sub_ddmmss (_xh, _r, _xh, _r, 0, (d)); \ _q++; \ if( _xh) { \ sub_ddmmss (_xh, _r, _xh, _r, 0, (d)); \ _q++; \ } \ } \ if( _r >= (d) ) { \ _r -= (d); \ _q++; \ } \ (r) = _r; \ (q) = _q; \ } while (0) /*-- mpiutil.c --*/ #ifdef M_DEBUG #define mpi_alloc_limb_space(n,f) mpi_debug_alloc_limb_space((n),(f), M_DBGINFO( __LINE__ ) ) #define mpi_free_limb_space(n) mpi_debug_free_limb_space((n), M_DBGINFO( __LINE__ ) ) mpi_ptr_t mpi_debug_alloc_limb_space( unsigned nlimbs, int sec, const char *info ); void mpi_debug_free_limb_space( mpi_ptr_t a, const char *info ); #else mpi_ptr_t mpi_alloc_limb_space( unsigned nlimbs, int sec ); void mpi_free_limb_space( mpi_ptr_t a ); #endif void mpi_assign_limb_space( MPI a, mpi_ptr_t ap, unsigned nlimbs ); /*-- mpi-bit.c --*/ void mpi_rshift_limbs( MPI a, unsigned int count ); void mpi_lshift_limbs( MPI a, unsigned int count ); /*-- mpihelp-add.c --*/ 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 mpihelp_add_n( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_ptr_t s2_ptr, mpi_size_t size); 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); /*-- mpihelp-sub.c --*/ 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 mpihelp_sub_n( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_ptr_t s2_ptr, mpi_size_t size); 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); /*-- mpihelp-cmp.c --*/ int mpihelp_cmp( mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size ); /*-- mpihelp-mul.c --*/ struct karatsuba_ctx { struct karatsuba_ctx *next; mpi_ptr_t tspace; mpi_size_t tspace_size; mpi_ptr_t tp; mpi_size_t tp_size; }; void mpihelp_release_karatsuba_ctx( struct karatsuba_ctx *ctx ); mpi_limb_t mpihelp_addmul_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size, mpi_limb_t s2_limb); mpi_limb_t mpihelp_submul_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size, mpi_limb_t s2_limb); void mpihelp_mul_n( mpi_ptr_t prodp, mpi_ptr_t up, mpi_ptr_t vp, mpi_size_t size); mpi_limb_t mpihelp_mul( mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize, mpi_ptr_t vp, mpi_size_t vsize); void mpih_sqr_n_basecase( mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size ); void mpih_sqr_n( mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size, mpi_ptr_t tspace); void mpihelp_mul_karatsuba_case( mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize, mpi_ptr_t vp, mpi_size_t vsize, struct karatsuba_ctx *ctx ); /*-- mpihelp-mul_1.c (or xxx/cpu/ *.S) --*/ mpi_limb_t mpihelp_mul_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size, mpi_limb_t s2_limb); /*-- mpihelp-div.c --*/ mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, mpi_limb_t divisor_limb); mpi_limb_t mpihelp_divrem( mpi_ptr_t qp, mpi_size_t qextra_limbs, mpi_ptr_t np, mpi_size_t nsize, mpi_ptr_t dp, mpi_size_t dsize); mpi_limb_t mpihelp_divmod_1( mpi_ptr_t quot_ptr, mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, mpi_limb_t divisor_limb); /*-- mpihelp-shift.c --*/ mpi_limb_t mpihelp_lshift( mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned cnt); mpi_limb_t mpihelp_rshift( mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned cnt); /* Define stuff for longlong.h. */ #define W_TYPE_SIZE BITS_PER_MPI_LIMB typedef mpi_limb_t UWtype; typedef unsigned int UHWtype; #if defined (__GNUC__) typedef unsigned int UQItype __attribute__ ((mode (QI))); typedef int SItype __attribute__ ((mode (SI))); typedef unsigned int USItype __attribute__ ((mode (SI))); typedef int DItype __attribute__ ((mode (DI))); typedef unsigned int UDItype __attribute__ ((mode (DI))); #else typedef unsigned char UQItype; typedef long SItype; typedef unsigned long USItype; #endif #ifdef __GNUC__ #include "mpi-inline.h" #endif #endif /*G10_MPI_INTERNAL_H*/ diff --git a/mpi/mpih-div.c b/mpi/mpih-div.c index 235a8107b..eedfabf55 100644 --- a/mpi/mpih-div.c +++ b/mpi/mpih-div.c @@ -1,534 +1,534 @@ /* mpihelp-div.c - MPI helper functions * Copyright (C) 1994, 1996 Free Software Foundation, Inc. * Copyright (C) 1998, 1999 Free Software Foundation, Inc. * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GnuPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * 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. */ #include #include #include #include "mpi-internal.h" #include "longlong.h" #ifndef UMUL_TIME #define UMUL_TIME 1 #endif #ifndef UDIV_TIME #define UDIV_TIME UMUL_TIME #endif /* FIXME: We should be using invert_limb (or invert_normalized_limb) * here (not udiv_qrnnd). */ mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, mpi_limb_t divisor_limb) { mpi_size_t i; mpi_limb_t n1, n0, r; - int dummy; + int dummy GNUPG_GCC_ATTR_UNUSED; /* Botch: Should this be handled at all? Rely on callers? */ if( !dividend_size ) return 0; /* If multiplication is much faster than division, and the * dividend is large, pre-invert the divisor, and use * only multiplications in the inner loop. * * This test should be read: * Does it ever help to use udiv_qrnnd_preinv? * && Does what we save compensate for the inversion overhead? */ if( UDIV_TIME > (2 * UMUL_TIME + 6) && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME ) { int normalization_steps; count_leading_zeros( normalization_steps, divisor_limb ); if( normalization_steps ) { mpi_limb_t divisor_limb_inverted; divisor_limb <<= normalization_steps; /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the * most significant bit (with weight 2**N) implicit. * * Special case for DIVISOR_LIMB == 100...000. */ if( !(divisor_limb << 1) ) divisor_limb_inverted = ~(mpi_limb_t)0; else udiv_qrnnd(divisor_limb_inverted, dummy, -divisor_limb, 0, divisor_limb); n1 = dividend_ptr[dividend_size - 1]; r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); /* Possible optimization: * if (r == 0 * && divisor_limb > ((n1 << normalization_steps) * | (dividend_ptr[dividend_size - 2] >> ...))) * ...one division less... */ for( i = dividend_size - 2; i >= 0; i--) { n0 = dividend_ptr[i]; UDIV_QRNND_PREINV(dummy, r, r, ((n1 << normalization_steps) | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), divisor_limb, divisor_limb_inverted); n1 = n0; } UDIV_QRNND_PREINV(dummy, r, r, n1 << normalization_steps, divisor_limb, divisor_limb_inverted); return r >> normalization_steps; } else { mpi_limb_t divisor_limb_inverted; /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the * most significant bit (with weight 2**N) implicit. * * Special case for DIVISOR_LIMB == 100...000. */ if( !(divisor_limb << 1) ) divisor_limb_inverted = ~(mpi_limb_t)0; else udiv_qrnnd(divisor_limb_inverted, dummy, -divisor_limb, 0, divisor_limb); i = dividend_size - 1; r = dividend_ptr[i]; if( r >= divisor_limb ) r = 0; else i--; for( ; i >= 0; i--) { n0 = dividend_ptr[i]; UDIV_QRNND_PREINV(dummy, r, r, n0, divisor_limb, divisor_limb_inverted); } return r; } } else { if( UDIV_NEEDS_NORMALIZATION ) { int normalization_steps; count_leading_zeros(normalization_steps, divisor_limb); if( normalization_steps ) { divisor_limb <<= normalization_steps; n1 = dividend_ptr[dividend_size - 1]; r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); /* Possible optimization: * if (r == 0 * && divisor_limb > ((n1 << normalization_steps) * | (dividend_ptr[dividend_size - 2] >> ...))) * ...one division less... */ for(i = dividend_size - 2; i >= 0; i--) { n0 = dividend_ptr[i]; udiv_qrnnd (dummy, r, r, ((n1 << normalization_steps) | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), divisor_limb); n1 = n0; } udiv_qrnnd (dummy, r, r, n1 << normalization_steps, divisor_limb); return r >> normalization_steps; } } /* No normalization needed, either because udiv_qrnnd doesn't require * it, or because DIVISOR_LIMB is already normalized. */ i = dividend_size - 1; r = dividend_ptr[i]; if(r >= divisor_limb) r = 0; else i--; for(; i >= 0; i--) { n0 = dividend_ptr[i]; udiv_qrnnd (dummy, r, r, n0, divisor_limb); } return r; } } /* Divide num (NP/NSIZE) by den (DP/DSIZE) and write * the NSIZE-DSIZE least significant quotient limbs at QP * and the DSIZE long remainder at NP. If QEXTRA_LIMBS is * non-zero, generate that many fraction bits and append them after the * other quotient limbs. * Return the most significant limb of the quotient, this is always 0 or 1. * * Preconditions: * 0. NSIZE >= DSIZE. * 1. The most significant bit of the divisor must be set. * 2. QP must either not overlap with the input operands at all, or * QP + DSIZE >= NP must hold true. (This means that it's * possible to put the quotient in the high part of NUM, right after the * remainder in NUM. * 3. NSIZE >= DSIZE, even if QEXTRA_LIMBS is non-zero. */ mpi_limb_t mpihelp_divrem( mpi_ptr_t qp, mpi_size_t qextra_limbs, mpi_ptr_t np, mpi_size_t nsize, mpi_ptr_t dp, mpi_size_t dsize) { mpi_limb_t most_significant_q_limb = 0; switch(dsize) { case 0: /* We are asked to divide by zero, so go ahead and do it! (To make the compiler not remove this statement, return the value.) */ return 1 / dsize; case 1: { mpi_size_t i; mpi_limb_t n1; mpi_limb_t d; d = dp[0]; n1 = np[nsize - 1]; if( n1 >= d ) { n1 -= d; most_significant_q_limb = 1; } qp += qextra_limbs; for( i = nsize - 2; i >= 0; i--) udiv_qrnnd( qp[i], n1, n1, np[i], d ); qp -= qextra_limbs; for( i = qextra_limbs - 1; i >= 0; i-- ) udiv_qrnnd (qp[i], n1, n1, 0, d); np[0] = n1; } break; case 2: { mpi_size_t i; mpi_limb_t n1, n0, n2; mpi_limb_t d1, d0; np += nsize - 2; d1 = dp[1]; d0 = dp[0]; n1 = np[1]; n0 = np[0]; if( n1 >= d1 && (n1 > d1 || n0 >= d0) ) { sub_ddmmss (n1, n0, n1, n0, d1, d0); most_significant_q_limb = 1; } for( i = qextra_limbs + nsize - 2 - 1; i >= 0; i-- ) { mpi_limb_t q; mpi_limb_t r; if( i >= qextra_limbs ) np--; else np[0] = 0; if( n1 == d1 ) { /* Q should be either 111..111 or 111..110. Need special * treatment of this rare case as normal division would * give overflow. */ q = ~(mpi_limb_t)0; r = n0 + d1; if( r < d1 ) { /* Carry in the addition? */ add_ssaaaa( n1, n0, r - d0, np[0], 0, d0 ); qp[i] = q; continue; } n1 = d0 - (d0 != 0?1:0); n0 = -d0; } else { udiv_qrnnd (q, r, n1, n0, d1); umul_ppmm (n1, n0, d0, q); } n2 = np[0]; q_test: if( n1 > r || (n1 == r && n0 > n2) ) { /* The estimated Q was too large. */ q--; sub_ddmmss (n1, n0, n1, n0, 0, d0); r += d1; if( r >= d1 ) /* If not carry, test Q again. */ goto q_test; } qp[i] = q; sub_ddmmss (n1, n0, r, n2, n1, n0); } np[1] = n1; np[0] = n0; } break; default: { mpi_size_t i; mpi_limb_t dX, d1, n0; np += nsize - dsize; dX = dp[dsize - 1]; d1 = dp[dsize - 2]; n0 = np[dsize - 1]; if( n0 >= dX ) { if(n0 > dX || mpihelp_cmp(np, dp, dsize - 1) >= 0 ) { mpihelp_sub_n(np, np, dp, dsize); n0 = np[dsize - 1]; most_significant_q_limb = 1; } } for( i = qextra_limbs + nsize - dsize - 1; i >= 0; i--) { mpi_limb_t q; mpi_limb_t n1, n2; mpi_limb_t cy_limb; if( i >= qextra_limbs ) { np--; n2 = np[dsize]; } else { n2 = np[dsize - 1]; MPN_COPY_DECR (np + 1, np, dsize - 1); np[0] = 0; } if( n0 == dX ) { /* This might over-estimate q, but it's probably not worth * the extra code here to find out. */ q = ~(mpi_limb_t)0; } else { mpi_limb_t r; udiv_qrnnd(q, r, n0, np[dsize - 1], dX); umul_ppmm(n1, n0, d1, q); while( n1 > r || (n1 == r && n0 > np[dsize - 2])) { q--; r += dX; if( r < dX ) /* I.e. "carry in previous addition?" */ break; n1 -= n0 < d1; n0 -= d1; } } /* Possible optimization: We already have (q * n0) and (1 * n1) * after the calculation of q. Taking advantage of that, we * could make this loop make two iterations less. */ cy_limb = mpihelp_submul_1(np, dp, dsize, q); if( n2 != cy_limb ) { mpihelp_add_n(np, np, dp, dsize); q--; } qp[i] = q; n0 = np[dsize - 1]; } } } return most_significant_q_limb; } /**************** * Divide (DIVIDEND_PTR,,DIVIDEND_SIZE) by DIVISOR_LIMB. * Write DIVIDEND_SIZE limbs of quotient at QUOT_PTR. * Return the single-limb remainder. * There are no constraints on the value of the divisor. * * QUOT_PTR and DIVIDEND_PTR might point to the same limb. */ mpi_limb_t mpihelp_divmod_1( mpi_ptr_t quot_ptr, mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, mpi_limb_t divisor_limb) { mpi_size_t i; mpi_limb_t n1, n0, r; - int dummy; + int dummy GNUPG_GCC_ATTR_UNUSED; if( !dividend_size ) return 0; /* If multiplication is much faster than division, and the * dividend is large, pre-invert the divisor, and use * only multiplications in the inner loop. * * This test should be read: * Does it ever help to use udiv_qrnnd_preinv? * && Does what we save compensate for the inversion overhead? */ if( UDIV_TIME > (2 * UMUL_TIME + 6) && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME ) { int normalization_steps; count_leading_zeros( normalization_steps, divisor_limb ); if( normalization_steps ) { mpi_limb_t divisor_limb_inverted; divisor_limb <<= normalization_steps; /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the * most significant bit (with weight 2**N) implicit. */ /* Special case for DIVISOR_LIMB == 100...000. */ if( !(divisor_limb << 1) ) divisor_limb_inverted = ~(mpi_limb_t)0; else udiv_qrnnd(divisor_limb_inverted, dummy, -divisor_limb, 0, divisor_limb); n1 = dividend_ptr[dividend_size - 1]; r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); /* Possible optimization: * if (r == 0 * && divisor_limb > ((n1 << normalization_steps) * | (dividend_ptr[dividend_size - 2] >> ...))) * ...one division less... */ for( i = dividend_size - 2; i >= 0; i--) { n0 = dividend_ptr[i]; UDIV_QRNND_PREINV( quot_ptr[i + 1], r, r, ((n1 << normalization_steps) | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), divisor_limb, divisor_limb_inverted); n1 = n0; } UDIV_QRNND_PREINV( quot_ptr[0], r, r, n1 << normalization_steps, divisor_limb, divisor_limb_inverted); return r >> normalization_steps; } else { mpi_limb_t divisor_limb_inverted; /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the * most significant bit (with weight 2**N) implicit. */ /* Special case for DIVISOR_LIMB == 100...000. */ if( !(divisor_limb << 1) ) divisor_limb_inverted = ~(mpi_limb_t) 0; else udiv_qrnnd(divisor_limb_inverted, dummy, -divisor_limb, 0, divisor_limb); i = dividend_size - 1; r = dividend_ptr[i]; if( r >= divisor_limb ) r = 0; else quot_ptr[i--] = 0; for( ; i >= 0; i-- ) { n0 = dividend_ptr[i]; UDIV_QRNND_PREINV( quot_ptr[i], r, r, n0, divisor_limb, divisor_limb_inverted); } return r; } } else { if(UDIV_NEEDS_NORMALIZATION) { int normalization_steps; count_leading_zeros (normalization_steps, divisor_limb); if( normalization_steps ) { divisor_limb <<= normalization_steps; n1 = dividend_ptr[dividend_size - 1]; r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); /* Possible optimization: * if (r == 0 * && divisor_limb > ((n1 << normalization_steps) * | (dividend_ptr[dividend_size - 2] >> ...))) * ...one division less... */ for( i = dividend_size - 2; i >= 0; i--) { n0 = dividend_ptr[i]; udiv_qrnnd (quot_ptr[i + 1], r, r, ((n1 << normalization_steps) | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), divisor_limb); n1 = n0; } udiv_qrnnd (quot_ptr[0], r, r, n1 << normalization_steps, divisor_limb); return r >> normalization_steps; } } /* No normalization needed, either because udiv_qrnnd doesn't require * it, or because DIVISOR_LIMB is already normalized. */ i = dividend_size - 1; r = dividend_ptr[i]; if(r >= divisor_limb) r = 0; else quot_ptr[i--] = 0; for(; i >= 0; i--) { n0 = dividend_ptr[i]; udiv_qrnnd( quot_ptr[i], r, r, n0, divisor_limb ); } return r; } }