From: mdw Date: Tue, 15 Oct 2002 19:18:31 +0000 (+0000) Subject: New operation to negate numbers. X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/commitdiff_plain/397041a943bdba47467a0393d7042c7fc99a5f3d New operation to negate numbers. --- diff --git a/mp-arith.c b/mp-arith.c index e47f301..a070675 100644 --- a/mp-arith.c +++ b/mp-arith.c @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: mp-arith.c,v 1.13 2002/10/15 00:19:40 mdw Exp $ + * $Id: mp-arith.c,v 1.14 2002/10/15 19:18:31 mdw Exp $ * * Basic arithmetic on multiprecision integers * @@ -30,6 +30,9 @@ /*----- Revision history --------------------------------------------------* * * $Log: mp-arith.c,v $ + * Revision 1.14 2002/10/15 19:18:31 mdw + * New operation to negate numbers. + * * Revision 1.13 2002/10/15 00:19:40 mdw * Bit setting and clearing functions. * @@ -271,6 +274,31 @@ int mp_cmp(const mp *a, const mp *b) return (+1); } +/* --- @mp_neg@ --- * + * + * Arguments: @mp *d@ = destination + * @mp *a@ = argument + * + * Returns: The negation of the argument. + * + * Use: Negates its argument. + */ + +mp *mp_neg(mp *d, mp *a) +{ + /* --- Surprising amounts of messing about required --- */ + + MP_SHRINK(a); + MP_COPY(a); + if (d) MP_DROP(d); + if (a->v == a->vl) { + return (a); + } + MP_DEST(a, MP_LEN(a), a->f); + a->f ^= MP_NEG; + return (a); +} + /* --- @mp_bitop@ --- * * * Arguments: @mp *d@ = destination @@ -850,6 +878,36 @@ static int tclr(dstr *v) return (ok); } +static int tneg(dstr *v) +{ + mp *a = *(mp **)v[0].buf; + mp *r = *(mp **)v[1].buf; + int ok = 1; + mp *n = mp_neg(MP_NEW, a); + if (!MP_EQ(r, n)) { + ok = 0; + fprintf(stderr, "\n*** neg failed\n"); + fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 10); + fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 10); + fputs("\n*** n = ", stderr); mp_writefile(n, stderr, 10); + fputc('\n', stderr); + } + mp_drop(n); + n = mp_neg(a, a); + if (!MP_EQ(r, n)) { + ok = 0; + fprintf(stderr, "\n*** neg failed\n"); + fputs("\n*** a* = ", stderr); mp_writefile(a, stderr, 10); + fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 10); + fputs("\n*** n = ", stderr); mp_writefile(n, stderr, 10); + fputc('\n', stderr); + } + mp_drop(a); + mp_drop(r); + assert(mparena_count(MPARENA_GLOBAL) == 0); + return (ok); +} + static int todd(dstr *v) { mp *a = *(mp **)v[0].buf; @@ -889,6 +947,7 @@ static test_chunk tests[] = { { "div", tdiv, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } }, { "bin2c", tbin, { &type_string, &type_mp, &type_mp, &type_mp, 0 } }, { "odd", todd, { &type_mp, &type_uint32, &type_mp, 0 } }, + { "neg", tneg, { &type_mp, &type_mp, 0 } }, { 0, 0, { 0 } }, }; diff --git a/mp.h b/mp.h index 6ccf523..f7a703c 100644 --- a/mp.h +++ b/mp.h @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: mp.h,v 1.14 2002/10/15 00:19:40 mdw Exp $ + * $Id: mp.h,v 1.15 2002/10/15 19:18:31 mdw Exp $ * * Simple multiprecision arithmetic * @@ -30,6 +30,9 @@ /*----- Revision history --------------------------------------------------* * * $Log: mp.h,v $ + * Revision 1.15 2002/10/15 19:18:31 mdw + * New operation to negate numbers. + * * Revision 1.14 2002/10/15 00:19:40 mdw * Bit setting and clearing functions. * @@ -656,78 +659,57 @@ extern mp *mp_loadb2c(mp */*d*/, const void */*pv*/, size_t /*sz*/); extern void mp_storeb2c(const mp */*m*/, void */*pv*/, size_t /*sz*/); -/*----- Simple arithmetic -------------------------------------------------*/ +/*----- Bit operations ----------------------------------------------------*/ -/* --- @mp_lsl@, @mp_lsr@ --- * +/* --- @mp_not@ --- * * * Arguments: @mp *d@ = destination * @mp *a@ = source - * @size_t n@ = number of bits to move * - * Returns: Result, @a@ shifted left or right by @n@. - */ + * Returns: The bitwise complement of the source. + */ -extern mp *mp_lsl(mp */*d*/, mp */*a*/, size_t /*n*/); -extern mp *mp_lsr(mp */*d*/, mp */*a*/, size_t /*n*/); +extern mp *mp_not(mp */*d*/, mp */*a*/); -/* --- @mp_lsl2c@, @mp_lsr2c@ --- * +/* --- @mp_bitop@ --- * * * Arguments: @mp *d@ = destination - * @mp *a@ = source - * @size_t n@ = number of bits to move + * @mp *a, *b@ = sources * - * Returns: Result, @a@ shifted left or right by @n@. Handles the - * pretence of sign-extension for negative numbers. + * Returns: The result of the given bitwise operation. These functions + * don't handle negative numbers at all sensibly. For that, use + * the @...2c@ variants. The functions are named after the + * truth tables they generate: + * + * a: 0011 + * b: 0101 + * @mpx_bitXXXX@ */ -extern mp *mp_lsl2c(mp */*d*/, mp */*a*/, size_t /*n*/); -extern mp *mp_lsr2c(mp */*d*/, mp */*a*/, size_t /*n*/); +#define MP_BITDECL(string) \ + extern mp *mp_bit##string(mp */*d*/, mp */*a*/, mp */*b*/); +MPX_DOBIN(MP_BITDECL) -/* --- @mp_testbit@ --- * - * - * Arguments: @mp *x@ = a large integer - * @unsigned long n@ = which bit to test +/* --- @mp_[n]and@, @mp_[n]or@, @mp_[n]xor@, @mp_not@ --- * * - * Returns: Nonzero if the bit is set, zero if not. + * Synonyms for the commonly-used functions. */ -extern int mp_testbit(mp */*x*/, unsigned long /*n*/); +#define mp_and mp_bit0001 +#define mp_or mp_bit0111 +#define mp_nand mp_bit1110 +#define mp_nor mp_bit1000 +#define mp_xor mp_bit0110 -/* --- @mp_testbit2c@ --- * +/* --- @mp_testbit@ --- * * * Arguments: @mp *x@ = a large integer * @unsigned long n@ = which bit to test * - * Returns: Nonzero if the bit is set, zero if not. Fakes up two's - * complement representation. - */ - -extern int mp_testbit2c(mp */*x*/, unsigned long /*n*/); - -/* --- @mp_eq@ --- * - * - * Arguments: @const mp *a, *b@ = two numbers - * - * Returns: Nonzero if the numbers are equal. - */ - -extern int mp_eq(const mp */*a*/, const mp */*b*/); - -#define MP_EQ(a, b) \ - ((((a)->f ^ (b)->f) & MP_NEG) == 0 && \ - mpx_ueq((a)->v, (a)->vl, (b)->v, (b)->vl)) - -/* --- @mp_cmp@ --- * - * - * Arguments: @const mp *a, *b@ = two numbers - * - * Returns: Less than, equal to or greater than zero, according to - * whether @a@ is less than, equal to or greater than @b@. + * Returns: Nonzero if the bit is set, zero if not. */ -extern int mp_cmp(const mp */*a*/, const mp */*b*/); - -#define MP_CMP(a, op, b) (mp_cmp((a), (b)) op 0) +extern int mp_testbit(mp */*x*/, unsigned long /*n*/); /* --- @mp_setbit@, @mp_clearbit@ --- * * @@ -741,58 +723,27 @@ extern int mp_cmp(const mp */*a*/, const mp */*b*/); extern mp *mp_setbit(mp */*d*/, mp */*x*/, unsigned long /*n*/); extern mp *mp_clearbit(mp */*d*/, mp */*x*/, unsigned long /*n*/); -/* --- @mp_setbit2c@, @mp_clearbit2c@ --- * - * - * Arguments: @mp *d@ = a destination - * @mp *x@ = a large integer - * @unsigned long n@ = which bit to modify - * - * Returns: The argument @x@, with the appropriate bit set or cleared. - * Fakes up two's complement representation. - */ - -extern mp *mp_setbit2c(mp */*d*/, mp */*x*/, unsigned long /*n*/); -extern mp *mp_clearbit2c(mp */*d*/, mp */*x*/, unsigned long /*n*/); - -/* --- @mp_bitop@ --- * +/* --- @mp_lsl@, @mp_lsr@ --- * * * Arguments: @mp *d@ = destination - * @mp *a, *b@ = sources - * - * Returns: The result of the given bitwise operation. These functions - * don't handle negative numbers at all sensibly. For that, use - * the @...2c@ variants. The functions are named after the - * truth tables they generate: - * - * a: 0011 - * b: 0101 - * @mpx_bitXXXX@ - */ - -#define MP_BITDECL(string) \ - extern mp *mp_bit##string(mp */*d*/, mp */*a*/, mp */*b*/); -MPX_DOBIN(MP_BITDECL) - -/* --- @mp_[n]and@, @mp_[n]or@, @mp_[n]xor@, @mp_not@ --- * + * @mp *a@ = source + * @size_t n@ = number of bits to move * - * Synonyms for the commonly-used functions. + * Returns: Result, @a@ shifted left or right by @n@. */ -#define mp_and mp_bit0001 -#define mp_or mp_bit0111 -#define mp_nand mp_bit1110 -#define mp_nor mp_bit1000 -#define mp_xor mp_bit0110 +extern mp *mp_lsl(mp */*d*/, mp */*a*/, size_t /*n*/); +extern mp *mp_lsr(mp */*d*/, mp */*a*/, size_t /*n*/); -/* --- @mp_not@ --- * +/* --- @mp_not2c@ --- * * * Arguments: @mp *d@ = destination * @mp *a@ = source * - * Returns: The bitwise complement of the source. - */ + * Returns: The sign-extended complement of the argument. + */ -extern mp *mp_not(mp */*d*/, mp */*a*/); +extern mp *mp_not2c(mp */*d*/, mp */*a*/); /* --- @mp_bitop2c@ --- * * @@ -824,15 +775,83 @@ MPX_DOBIN(MP_BIT2CDECL) #define mp_nor2c mp_bit10002c #define mp_xor2c mp_bit01102c -/* --- @mp_not2c@ --- * +/* --- @mp_lsl2c@, @mp_lsr2c@ --- * * * Arguments: @mp *d@ = destination * @mp *a@ = source + * @size_t n@ = number of bits to move * - * Returns: The sign-extended complement of the argument. + * Returns: Result, @a@ shifted left or right by @n@. Handles the + * pretence of sign-extension for negative numbers. */ -extern mp *mp_not2c(mp */*d*/, mp */*a*/); +extern mp *mp_lsl2c(mp */*d*/, mp */*a*/, size_t /*n*/); +extern mp *mp_lsr2c(mp */*d*/, mp */*a*/, size_t /*n*/); + +/* --- @mp_testbit2c@ --- * + * + * Arguments: @mp *x@ = a large integer + * @unsigned long n@ = which bit to test + * + * Returns: Nonzero if the bit is set, zero if not. Fakes up two's + * complement representation. + */ + +extern int mp_testbit2c(mp */*x*/, unsigned long /*n*/); + +/* --- @mp_setbit2c@, @mp_clearbit2c@ --- * + * + * Arguments: @mp *d@ = a destination + * @mp *x@ = a large integer + * @unsigned long n@ = which bit to modify + * + * Returns: The argument @x@, with the appropriate bit set or cleared. + * Fakes up two's complement representation. + */ + +extern mp *mp_setbit2c(mp */*d*/, mp */*x*/, unsigned long /*n*/); +extern mp *mp_clearbit2c(mp */*d*/, mp */*x*/, unsigned long /*n*/); + +/*----- Comparisons -------------------------------------------------------*/ + +/* --- @mp_eq@ --- * + * + * Arguments: @const mp *a, *b@ = two numbers + * + * Returns: Nonzero if the numbers are equal. + */ + +extern int mp_eq(const mp */*a*/, const mp */*b*/); + +#define MP_EQ(a, b) \ + ((((a)->f ^ (b)->f) & MP_NEG) == 0 && \ + mpx_ueq((a)->v, (a)->vl, (b)->v, (b)->vl)) + +/* --- @mp_cmp@ --- * + * + * Arguments: @const mp *a, *b@ = two numbers + * + * Returns: Less than, equal to or greater than zero, according to + * whether @a@ is less than, equal to or greater than @b@. + */ + +extern int mp_cmp(const mp */*a*/, const mp */*b*/); + +#define MP_CMP(a, op, b) (mp_cmp((a), (b)) op 0) + +/*----- Arithmetic operations ---------------------------------------------*/ + +/* --- @mp_neg@ --- * + * + * Arguments: @mp *d@ = destination + * @mp *a@ = argument + * + * Returns: The negation of the argument. + * + * Use: Negates its argument. + */ + +extern mp *mp_neg(mp */*d*/, mp */*a*/); /* --- @mp_add@ --- * * diff --git a/tests/mp b/tests/mp index ea51574..6fe61e5 100644 --- a/tests/mp +++ b/tests/mp @@ -1,6 +1,6 @@ # Test vectors for MP functions # -# $Id: mp,v 1.11 2002/10/15 00:19:40 mdw Exp $ +# $Id: mp,v 1.12 2002/10/15 19:18:31 mdw Exp $ add { 5 4 9; 5 -4 1; -5 4 -1; -5 -4 -9; @@ -51,6 +51,12 @@ clrbit { -1 1 -3; } +neg { + 0 0; + 15 -15; + -15 15; +} + odd { 1 0 1; 2 1 1;