/* arith01.c Copyright (C) 1990-2007 Codemist Ltd */
/*
* Arithmetic functions.
* Addition of generic numbers
* and in particular a lot of bignum support.
*
*/
/*
* This code may be used and modified, and redistributed in binary
* or source form, subject to the "CCL Public License", which should
* accompany it. This license is a variant on the BSD license, and thus
* permits use of code derived from this in either open and commercial
* projects: but it does require that updates to this code be made
* available back to the originators of the package.
* Before merging other code in with this or linking this code
* with other packages or libraries please check that the license terms
* of the other material are compatible with those of this.
*/
/* Signature: 010b84fd 02-Jan-2008 */
#include "headers.h"
/*
* I start off with a collection of utility functions that create
* Lisp structures to represent various sorts of numbers
* and which extract values from same.
* The typedefs that explain the layout of these structures are in "tags.h"
*/
Lisp_Object make_one_word_bignum(int32_t n)
/*
* n is an integer - create a bignum representation of it. This is
* done when n is outside the range 0xf8000000 to 0x07ffffff.
*/
{ Lisp_Object w = getvector(TAG_NUMBERS, TYPE_BIGNUM, CELL+4);
Lisp_Object nil;
errexit();
bignum_digits(w)[0] = n;
if (SIXTY_FOUR_BIT) bignum_digits(w)[1] = 0; /* padding */
return w;
}
Lisp_Object make_two_word_bignum(int32_t a1, uint32_t a0)
/*
* This make a 2-word bignum from the 2-word value (a1,a0), where it
* must have been arranged already that a1 and a0 are correctly
* normalized to put in the two words as indicated.
*/
{
Lisp_Object w = getvector(TAG_NUMBERS, TYPE_BIGNUM, CELL+8);
Lisp_Object nil;
errexit();
bignum_digits(w)[0] = a0;
bignum_digits(w)[1] = a1;
if (!SIXTY_FOUR_BIT) bignum_digits(w)[2] = 0;
return w;
}
#ifdef COMMON
Lisp_Object make_sfloat(double d)
/*
* Turn a regular floating point value into a Lisp "short float", which
* is an immediate object obtained by using the bottom 4 bits of a 32-bit
* word as tag, and the rest as just whatever would stand for a regular
* single precision value. In doing the conversion here I ignore
* rounding etc - short floats are to save heap turn-over, but will
* not give robust numeric results.
*/
{
Float_union w;
w.f = (float)d;
return (w.i & ~(int32_t)0xf) + TAG_SFLOAT;
}
#endif
Lisp_Object make_boxfloat(double a, int32_t type)
/*
* Make a boxed float (single, double or long according to the type specifier)
* if type==0 this makes a short float
*/
{
Lisp_Object r, nil;
#ifndef COMMON
CSL_IGNORE(type);
#endif
#ifdef COMMON
switch (type)
{
case 0:
{ Float_union aa;
aa.f = (float)a;
return (aa.i & ~(intptr_t)0xf) + TAG_SFLOAT;
}
case TYPE_SINGLE_FLOAT:
r = getvector(TAG_BOXFLOAT, TYPE_SINGLE_FLOAT, sizeof(Single_Float));
errexit();
single_float_val(r) = (float)a;
return r;
default: /* TYPE_DOUBLE_FLOAT I hope */
#endif
r = getvector(TAG_BOXFLOAT, TYPE_DOUBLE_FLOAT, SIZEOF_DOUBLE_FLOAT);
errexit();
double_float_val(r) = a;
return r;
#ifdef COMMON
case TYPE_LONG_FLOAT:
r = getvector(TAG_BOXFLOAT, TYPE_LONG_FLOAT, SIZEOF_LONG_FLOAT);
errexit();
long_float_val(r) = a;
return r;
}
#endif
}
static double bignum_to_float(Lisp_Object v, int32_t h, int *xp)
/*
* Convert a Lisp bignum to get a floating point value. This uses at most the
* top 3 digits of the bignum's representation since that is enough to achieve
* full double precision accuracy.
* This can not overflow, because it leaves an exponent-adjustment value
* in *xp. You need ldexp(r, *xp) afterwards.
*/
{
int32_t n = (h-CELL-4)/4; /* Last index into the data */
int x = 31*(int)n;
int32_t msd = (int32_t)bignum_digits(v)[n];
/* NB signed conversion on next line */
double r = (double)msd;
switch (n)
{
default: /* for very big numbers combine in 3 digits */
r = TWO_31*r + (double)bignum_digits(v)[--n];
x -= 31;
/* drop through */
case 1: r = TWO_31*r + (double)bignum_digits(v)[--n];
x -= 31;
/* drop through */
case 0: break; /* do no more */
}
*xp = x;
return r;
}
double float_of_number(Lisp_Object a)
/*
* Return a (double precision) floating point value for the given Lisp
* number, or 0.0 in case of trouble. This is often called in circumstances
* where I already know the type of its argument and so its type-dispatch
* is unnecessary - in doing so I am trading off performance against
* code repetition.
*/
{
if (is_fixnum(a)) return (double)int_of_fixnum(a);
#ifdef COMMON
else if (is_sfloat(a))
{ Float_union w;
w.i = a - TAG_SFLOAT;
return (double)w.f;
}
#endif
else if (is_bfloat(a))
{ int32_t h = type_of_header(flthdr(a));
switch (h)
{
#ifdef COMMON
case TYPE_SINGLE_FLOAT:
return (double)single_float_val(a);
#endif
case TYPE_DOUBLE_FLOAT:
return double_float_val(a);
#ifdef COMMON
case TYPE_LONG_FLOAT:
return (double)long_float_val(a);
#endif
default:
return 0.0;
}
}
else
{ Header h = numhdr(a);
int x1;
double r1;
switch (type_of_header(h))
{
case TYPE_BIGNUM:
r1 = bignum_to_float(a, length_of_header(h), &x1);
return ldexp(r1, x1);
#ifdef COMMON
case TYPE_RATNUM:
{ int x2;
Lisp_Object na = numerator(a);
a = denominator(a);
if (is_fixnum(na)) r1 = float_of_number(na), x1 = 0;
else r1 = bignum_to_float(na,
length_of_header(numhdr(na)), &x1);
if (is_fixnum(a)) r1 = r1 / float_of_number(a), x2 = 0;
else r1 = r1 / bignum_to_float(a,
length_of_header(numhdr(a)), &x2);
/* Floating point overflow can only arise in this ldexp() */
return ldexp(r1, x1 - x2);
}
#endif
default:
/*
* If the value was non-numeric or a complex number I hand back 0.0,
* and since I am supposed to have checked the object type already
* this OUGHT not to arrive - bit raising an exception seems over-keen.
*/
return 0.0;
}
}
}
int32_t thirty_two_bits(Lisp_Object a)
/*
* return a 32 bit integer value for the Lisp integer (fixnum or bignum)
* passed down - ignore any higher order bits and return 0 if the arg was
* floating, rational etc or not a number at all. Only really wanted where
* links between C-specific code (that might really want 32-bit values)
* and Lisp are being coded.
*/
{
switch ((int)a & TAG_BITS)
{
case TAG_FIXNUM:
return int_of_fixnum(a);
case TAG_NUMBERS:
if (is_bignum(a))
{ int len = bignum_length(a);
/*
* Note that I keep 31 bits per word and use a 2s complement representation.
* thus if I have a one-word bignum I just want its contents but in all
* other cases I need just one bit from the next word up.
*/
if (len == 8) return bignum_digits(a)[0]; /* One word bignum */
return bignum_digits(a)[0] | (bignum_digits(a)[1] << 31);
}
/* else drop through */
case TAG_BOXFLOAT:
default:
/*
* return 0 for all non-fixnums
*/
return 0;
}
}
#ifdef HAVE_INT64_T
int64_t sixty_four_bits(Lisp_Object a)
{
return (int64_t)thirty_two_bits(a); /* Inadequate really! */
}
#endif
#ifdef COMMON
Lisp_Object make_complex(Lisp_Object r, Lisp_Object i)
{
Lisp_Object v, nil = C_nil;
/*
* Here r and i are expected to be either both rational (which in this
* context includes the case of integer values) or both of the same
* floating point type. It is assumed that this has already been
* arranged by here.
*/
if (i == fixnum_of_int(0)) return r;
stackcheck2(0, r, i);
push2(r, i);
v = getvector(TAG_NUMBERS, TYPE_COMPLEX_NUM, sizeof(Complex_Number));
/*
* The vector r has uninitialized contents here - dodgy. If the call
* to getvector succeeded then I fill it in, otherwise I will not
* refer to it again, and I think that unreferenced vectors containing junk
* are OK.
*/
pop2(i, r);
errexit();
real_part(v) = r;
imag_part(v) = i;
return v;
}
Lisp_Object make_ratio(Lisp_Object p, Lisp_Object q)
/*
* By the time this is called (p/q) must be in its lowest terms, q>0
*/
{
Lisp_Object v, nil = C_nil;
if (q == fixnum_of_int(1)) return p;
stackcheck2(0, p, q);
push2(p, q);
v = getvector(TAG_NUMBERS, TYPE_RATNUM, sizeof(Rational_Number));
pop2(q, p);
errexit();
numerator(v) = p;
denominator(v) = q;
return v;
}
#endif
/*
* The next bit of code seems pretty dreadful, but I think that is just
* what generic arithmetic is all about. The code for plus2 is written
* as a dispatch function into over 30 separate possible type-specific
* versions of the code. In a very few simple (and performance-critical)
* cases the code is written in-line in plus2 - in particular arithmetic
* on fixnums is done that way. Similarly for other cases.
* I Use one-character suffices to remind me about types:
* i fixnum
* b bignum
* r ratio
* s short float
* f boxed float (single/double/long)
* c complex
*
* Throughout this code I am going to IGNORE floating point exceptions,
* at least for a first attempt. Decent detection of and recovery after
* floating point overflow seems an extra unpleasant distraction! Note
* that C allows me to trap the SIGFPE exception, but returning from
* the exception handler gives undefined behaviour - one is expected
* to longjmp out, which means accepting the cost of using setjmp.
*
* It would perhaps be reasonable to write the dispatch code as a big
* macro so that the versions for plus, times etc could all be kept
* in step - I have not done that (a) because the macro would have been
* bigger than I like macros to be (b) it would have involved token-
* splicing (or VERY many parameters) to generate the names of the
* separate type-specific procedures and (c) doing it by hand allows me
* total flexibility about coding various cases in-line.
*/
#ifdef COMMON
static Lisp_Object plusis(Lisp_Object a, Lisp_Object b)
{
Float_union bb;
bb.i = b - TAG_SFLOAT;
bb.f = (float)((float)int_of_fixnum(a) + bb.f);
return (bb.i & ~(int32_t)0xf) + TAG_SFLOAT;
}
#endif
/*
* Bignums are represented as vectors where the most significant 32-bit
* digit is treated as signed, and the remaining ones are unsigned.
*/
static Lisp_Object plusib(Lisp_Object a, Lisp_Object b)
/*
* Add a fixnum to a bignum, returning a result as a fixnum or bignum
* depending on its size. This seems much nastier than one would have
* hoped.
*/
{
int32_t len = bignum_length(b)-CELL, i, sign = int_of_fixnum(a), s;
Lisp_Object c, nil;
len = len/4; /* This is always 4 because even on a 64-bit */
/* machine where CELL=8 I use 4-byte B-digits */
if (len == 1)
{ int32_t t;
/*
* Partly because it will be a common case and partly because it has
* various special cases I have special purpose code to cope with
* adding a fixnum to a one-word bignum.
*/
s = (int32_t)bignum_digits(b)[0] + sign;
t = s + s;
if (top_bit_set(s ^ t)) /* needs to turn into two-word bignum */
{ if (s < 0) return make_two_word_bignum(-1, clear_top_bit(s));
else return make_two_word_bignum(0, s);
}
t = s & fix_mask; /* Will it fit as a fixnum? */
if (t == 0 || t == fix_mask) return fixnum_of_int(s);
/* here the result is a one-word bignum */
return make_one_word_bignum(s);
}
/*
* Now, after all the silly cases have been handled, I have a calculation
* which seems set to give a multi-word result. The result here can at
* least never shrink to a fixnum since subtracting a fixnum can at
* most shrink the length of a number by one word. I omit the stack-
* check here in the hope that code here never nests enough for trouble.
*/
push(b);
c = getvector(TAG_NUMBERS, TYPE_BIGNUM, CELL+4*len);
pop(b);
errexit();
s = bignum_digits(b)[0] + clear_top_bit(sign);
bignum_digits(c)[0] = clear_top_bit(s);
if (sign >= 0) sign = 0; else sign = 0x7fffffff; /* extend the sign */
len--;
for (i=1; i<len; i++)
{ s = bignum_digits(b)[i] + sign + top_bit(s);
bignum_digits(c)[i] = clear_top_bit(s);
}
/* Now just the most significant digit remains to be processed */
if (sign != 0) sign = -1;
{ s = bignum_digits(b)[i] + sign + top_bit(s);
if (!signed_overflow(s)) /* did it overflow? */
{
/*
* Here the most significant digit did not produce an overflow, but maybe
* what we actually had was some cancellation and the MSD is now zero
* or -1, so that the number should shrink...
*/
if ((s == 0 && (bignum_digits(c)[i-1] & 0x40000000) == 0) ||
(s == -1 && (bignum_digits(c)[i-1] & 0x40000000) != 0))
{ /* shrink the number */
numhdr(c) -= pack_hdrlength(1L);
if (s == -1) bignum_digits(c)[i-1] |= ~0x7fffffff;
/*
* Now sometimes the shrinkage will leave a padding word, sometimes it
* will really allow me to save space. As a jolly joke with a 64-bit
* system I need padding if there have been an odd number of (32-bit)
* words of bignum data while with a 32-bit system the header word is
* 32-bits wide and I need padding if there are ar even number of additional
* data words.
*/
if ((SIXTY_FOUR_BIT && ((i & 1) != 0)) ||
(!SIXTY_FOUR_BIT && ((i & 1) == 0)))
{ bignum_digits(c)[i] = 0; /* leave the unused word tidy */
return c;
}
/*
* Having shrunk the number I am leaving a doubleword of unallocated space
* in the heap. Dump a header word into it to make it look like an
* 8-byte bignum since that will allow the garbage collector to handle it.
* It I left it containing arbitrary junk I could wreck myself. The
* make_bighdr(2L) makes a header for a number that fills 2 32-bit words
* in all.
*/
*(Header *)&bignum_digits(c)[i] = make_bighdr(2L);
return c;
}
bignum_digits(c)[i] = s; /* length unchanged */
return c;
}
/*
* Here the result is one word longer than the input-bignum.
* Once again SOMTIMES this will not involve allocating more store,
* but just encroaching into the previously unused word that was padding
* things out to a multiple of 8 bytes.
*/
if ((SIXTY_FOUR_BIT && ((i & 1) == 0)) ||
(!SIXTY_FOUR_BIT && ((i & 1) == 1)))
{ bignum_digits(c)[i++] = clear_top_bit(s);
bignum_digits(c)[i] = top_bit_set(s) ? -1 : 0;
numhdr(c) += pack_hdrlength(1L);
return c;
}
push(c);
/*
* NB on the next line there is a +8. One +4 is because I had gone len--
* somewhere earlier. The other +4 is to increase the length of the number
* by one word.
*/
b = getvector(TAG_NUMBERS, TYPE_BIGNUM, CELL+8+4*len);
pop(c);
errexit();
for (i=0; i<len; i++)
bignum_digits(b)[i] = bignum_digits(c)[i];
/*
* I move the top digit across by hand since if the number is negative
* I must lost its top bit
*/
bignum_digits(b)[i++] = clear_top_bit(s);
/* Now the one-word extension to the number */
bignum_digits(b)[i++] = top_bit_set(s) ? -1 : 0;
/*
* Finally because I know that I expanded into a new doubleword I should
* tidy up the second word of the newly allocated pair.
*/
bignum_digits(b)[i] = 0;
return b;
}
}
#ifdef COMMON
static Lisp_Object plusir(Lisp_Object a, Lisp_Object b)
/*
* fixnum and ratio, but also valid for bignum and ratio.
* Note that if the inputs were in lowest terms there is no need for
* and GCD calculations here.
*/
{
Lisp_Object nil;
push(b);
a = times2(a, denominator(b));
nil = C_nil;
if (!exception_pending()) a = plus2(a, numerator(stack[0]));
pop(b);
errexit();
return make_ratio(a, denominator(b));
}
static Lisp_Object plusic(Lisp_Object a, Lisp_Object b)
/*
* real of any sort plus complex.
*/
{
Lisp_Object nil;
push(b);
a = plus2(a, real_part(b));
pop(b);
errexit();
/*
* make_complex() takes responsibility for mapping #C(n 0) onto n
*/
return make_complex(a, imag_part(b));
}
#endif
static Lisp_Object plusif(Lisp_Object a, Lisp_Object b)
/*
* Fixnum plus boxed-float.
*/
{
double d = (double)int_of_fixnum(a) + float_of_number(b);
return make_boxfloat(d, type_of_header(flthdr(b)));
}
#ifdef COMMON
#define plussi(a, b) plusis(b, a)
#define plussb(a, b) plusbs(b, a)
#define plussr(a, b) plusrs(b, a)
#define plussc(a, b) plusic(a, b)
#endif
static Lisp_Object plussf(Lisp_Object a, Lisp_Object b)
/*
* This can be used for any rational value plus a boxed-float. plusif()
* is separated just for (minor) efficiency reasons.
*/
{
double d = float_of_number(a) + float_of_number(b);
return make_boxfloat(d, type_of_header(flthdr(b)));
}
#define plusbi(a, b) plusib(b, a)
#ifdef COMMON
static Lisp_Object plusbs(Lisp_Object a, Lisp_Object b)
{
double d = float_of_number(a) + float_of_number(b);
return make_sfloat(d);
}
#endif
Lisp_Object lengthen_by_one_bit(Lisp_Object a, int32_t msd)
/*
* (a) is a bignum, and arithmetic on it has (just) caused overflow
* in its top word - I just need to stick on another word. (msd) is the
* current top word, and its sign will be used to decide on the value
* that must be appended.
*/
{
int32_t len = bignum_length(a);
/*
* Sometimes I need to allocate a new vector and copy data across into it
*/
if ((len & 4) == 0)
{ Lisp_Object b, nil;
int32_t i;
push(a);
b = getvector(TAG_NUMBERS, TYPE_BIGNUM, len+4);
pop(a);
errexit();
len = (len-CELL)/4;
for (i=0; i<len; i++)
bignum_digits(b)[i] = clear_top_bit(bignum_digits(a)[i]);
bignum_digits(b)[len] = top_bit_set(msd) ? -1 : 0;
bignum_digits(b)[len+1] = 0;
return b;
}
else
/*
* .. whereas sometimes I have a spare word already available.
*/
{ numhdr(a) += pack_hdrlength(1L);
len = (len-CELL)/4;
bignum_digits(a)[len-1] = clear_top_bit(bignum_digits(a)[len-1]);
bignum_digits(a)[len] = top_bit_set(msd) ? -1 : 0;
return a;
}
}
static Lisp_Object plusbb(Lisp_Object a, Lisp_Object b)
/*
* add two bignums.
*/
{
int32_t la = bignum_length(a),
lb = bignum_length(b),
i, s, carry;
Lisp_Object c, nil;
if (la < lb) /* maybe swap order of args */
{ Lisp_Object t = a;
int32_t t1;
a = b; b = t;
t1 = la; la = lb; lb = t1;
}
/*
* now (a) is AT LEAST as long as b. I have special case code for
* when both args are single-word bignums, since I expect that to be
* an especially common case.
*/
if (la == CELL+4) /* and hence b also has only 1 digit */
{ int32_t va = bignum_digits(a)[0],
vb = bignum_digits(b)[0],
vc = va + vb;
if (signed_overflow(vc)) /* we have a 2-word bignum result */
{ Lisp_Object w = getvector(TAG_NUMBERS, TYPE_BIGNUM, CELL+8);
errexit();
bignum_digits(w)[0] = clear_top_bit(vc);
bignum_digits(w)[1] = top_bit_set(vc) ? -1 : 0;
if (!SIXTY_FOUR_BIT) bignum_digits(w)[2] = 0;
return w;
}
/*
* here the result fits into one word - maybe it will squash down into
* a fixnum?
*/
else
{ vb = vc & fix_mask;
if (vb == 0 || vb == fix_mask) return fixnum_of_int(vc);
else return make_one_word_bignum(vc);
}
}
push2(a, b);
c = getvector(TAG_NUMBERS, TYPE_BIGNUM, la);
pop2(b, a);
errexit();
la = (la-CELL)/4 - 1;
lb = (lb-CELL)/4 - 1;
carry = 0;
/*
* Add all but the top digit of b
*/
for (i=0; i<lb; i++)
{ carry = bignum_digits(a)[i] + bignum_digits(b)[i] + top_bit(carry);
bignum_digits(c)[i] = clear_top_bit(carry);
}
if (la == lb) s = bignum_digits(b)[i];
else
/*
* If a is strictly longer than b I sign extend b here and add in as many
* copies of 0 or -1 as needbe to get up to the length of a.
*/
{ s = bignum_digits(b)[i];
carry = bignum_digits(a)[i] + clear_top_bit(s) + top_bit(carry);
bignum_digits(c)[i] = clear_top_bit(carry);
if (s < 0) s = -1; else s = 0;
for (i++; i<la; i++)
{ carry = bignum_digits(a)[i] + clear_top_bit(s) + top_bit(carry);
bignum_digits(c)[i] = clear_top_bit(carry);
}
}
/*
* the most significant digit is added using signed arithmetic so that I
* can tell if it overflowed.
*/
carry = bignum_digits(a)[i] + s + top_bit(carry);
if (!signed_overflow(carry))
{
/*
* Here the number has not expanded - but it may be shrinking, and it can
* shrink by any number of words, all the way down to a fixnum maybe. Note
* that I started with at least a 2-word bignum here.
*/
int32_t msd;
bignum_digits(c)[i] = carry;
if (carry == 0)
{ int32_t j = i-1;
while ((msd = bignum_digits(c)[j]) == 0 && j > 0) j--;
/*
* ... but I may need a zero word on the front if the next word down
* has its top bit set... (top of 31 bits, that is)
*/
if ((msd & 0x40000000) != 0)
{ j++;
if (i == j) return c;
}
if (j == 0)
{ int32_t s = bignum_digits(c)[0];
if ((s & fix_mask) == 0) return fixnum_of_int(s);
}
/*
* If I am shrinking by one word and had an even length to start with
* I do not have to mess about so much.
*/
if ((SIXTY_FOUR_BIT && (j == i-1) && ((i & 1) != 0)) ||
(!SIXTY_FOUR_BIT && (j == i-1) && ((i & 1) == 0)))
{ numhdr(c) -= pack_hdrlength(1L);
return c;
}
numhdr(c) -= pack_hdrlength(i - j);
if (SIXTY_FOUR_BIT)
{ i = (i+2) & ~1;
j = (j+2) & ~1; /* Round up to odd index */
}
else
{ i = (i+1) | 1;
j = (j+1) | 1; /* Round up to odd index */
}
/*
* I forge a header word to allow the garbage collector to skip over
* (and in due course reclaim) the space that turned out not to be needed.
*/
bignum_digits(c)[j] = make_bighdr(i - j);
return c;
}
/*
* Now do all the same sorts of things but this time for negative numbers.
*/
else if (carry == -1)
{ int32_t j = i-1;
msd = carry; /* in case j = 0 */
while ((msd = bignum_digits(c)[j]) == 0x7fffffff && j > 0) j--;
if ((msd & 0x40000000) == 0)
{ j++;
if (i == j) return c;
}
if (j == 0)
{ int32_t s = bignum_digits(c)[0] | ~0x7fffffff;
if ((s & fix_mask) == fix_mask) return fixnum_of_int(s);
}
if ((SIXTY_FOUR_BIT && (j == i-1) && ((i & 1) != 0)) ||
(!SIXTY_FOUR_BIT && (j == i-1) && ((i & 1) == 0)))
{ bignum_digits(c)[i] = 0;
bignum_digits(c)[i-1] |= ~0x7fffffff;
numhdr(c) -= pack_hdrlength(1);
return c;
}
numhdr(c) -= pack_hdrlength(i - j);
bignum_digits(c)[j+1] = 0;
bignum_digits(c)[j] |= ~0x7fffffff;
if (SIXTY_FOUR_BIT)
{ i = (i+2) & ~1;
j = (j+2) & ~1; /* Round up to odd index */
}
else
{ i = (i+1) | 1;
j = (j+1) | 1; /* Round up to odd index */
}
bignum_digits(c)[j] = make_bighdr(i - j);
return c;
}
return c;
}
else
{ bignum_digits(c)[i] = carry;
return lengthen_by_one_bit(c, carry);
}
}
#ifdef COMMON
#define plusbr(a, b) plusir(a, b)
#define plusbc(a, b) plusic(a, b)
#endif
#define plusbf(a, b) plussf(a, b)
#ifdef COMMON
#define plusri(a, b) plusir(b, a)
#define plusrs(a, b) plusbs(a, b)
#define plusrb(a, b) plusri(a, b)
static Lisp_Object plusrr(Lisp_Object a, Lisp_Object b)
/*
* Adding two ratios involves some effort to keep the result in
* lowest terms.
*/
{
Lisp_Object nil = C_nil;
Lisp_Object na = numerator(a), nb = numerator(b);
Lisp_Object da = denominator(a), db = denominator(b);
Lisp_Object w = nil;
push5(na, nb, da, db, nil);
#define g stack[0]
#define db stack[-1]
#define da stack[-2]
#define nb stack[-3]
#define na stack[-4]
g = gcd(da, db);
nil = C_nil;
if (exception_pending()) goto fail;
/*
* all the calls to quot2() in this procedure are expected - nay required -
* to give exact integer quotients.
*/
db = quot2(db, g);
nil = C_nil;
if (exception_pending()) goto fail;
g = quot2(da, g);
nil = C_nil;
if (exception_pending()) goto fail;
na = times2(na, db);
nil = C_nil;
if (exception_pending()) goto fail;
nb = times2(nb, g);
nil = C_nil;
if (exception_pending()) goto fail;
na = plus2(na, nb);
nil = C_nil;
if (exception_pending()) goto fail;
da = times2(da, db);
nil = C_nil;
if (exception_pending()) goto fail;
g = gcd(na, da);
nil = C_nil;
if (exception_pending()) goto fail;
na = quot2(na, g);
nil = C_nil;
if (exception_pending()) goto fail;
da = quot2(da, g);
nil = C_nil;
if (exception_pending()) goto fail;
w = make_ratio(na, da);
/*
* All the goto statements and the label seem a fair way of expressing
* the common action that has to be taken if an error or interrupt is
* detected during any of the intermediate steps here. Anyone who
* objects can change it if they really want...
*/
fail:
popv(5);
return w;
#undef na
#undef nb
#undef da
#undef db
#undef g
}
#define plusrc(a, b) plusic(a, b)
#define plusrf(a, b) plussf(a, b)
#define plusci(a, b) plusic(b, a)
#define pluscs(a, b) plussc(b, a)
#define pluscb(a, b) plusbc(b, a)
#define pluscr(a, b) plusrc(b, a)
static Lisp_Object pluscc(Lisp_Object a, Lisp_Object b)
/*
* Add complex values.
*/
{
Lisp_Object c, nil;
push2(a, b);
c = plus2(imag_part(a), imag_part(b));
pop2(b, a);
errexit();
a = plus2(real_part(a), real_part(b));
errexit();
return make_complex(a, c);
}
#define pluscf(a, b) plusfc(b, a)
#endif
#define plusfi(a, b) plusif(b, a)
#ifdef COMMON
#define plusfs(a, b) plussf(b, a)
#endif
#define plusfb(a, b) plusbf(b, a)
#ifdef COMMON
#define plusfr(a, b) plusrf(b, a)
#define plusfc(a, b) plusic(a, b)
#endif
static Lisp_Object plusff(Lisp_Object a, Lisp_Object b)
/*
* Add two boxed floats - the type of the result must match the
* longer of the types of the arguments, hence the extra
* messing about.
*/
{
#ifdef COMMON
int32_t ha = type_of_header(flthdr(a)), hb = type_of_header(flthdr(b));
#endif
double d;
/*
* This is written as a declaration followed by a separate assignment to
* d because I hit a compiler bug on a VAX once otherwise.
*/
d = float_of_number(a) + float_of_number(b);
#ifdef COMMON
if (ha == TYPE_LONG_FLOAT || hb == TYPE_LONG_FLOAT)
ha = TYPE_LONG_FLOAT;
else if (ha == TYPE_DOUBLE_FLOAT || hb == TYPE_DOUBLE_FLOAT)
ha = TYPE_DOUBLE_FLOAT;
else ha = TYPE_SINGLE_FLOAT;
return make_boxfloat(d, ha);
#else
return make_boxfloat(d, TYPE_DOUBLE_FLOAT);
#endif
}
/*
* and now for the dispatch code...
*/
/*
* The following verifies that a number is properly formatted - a
* fixnum if small enough or a decently normalised bignum. For use when
* there is suspicion of a bug wrt such matters. Call is
* validate_number("msg", numberToCheck, nX, nY)
* where nX and nY must be numbers and are shown in any
* diagnostic.
*/
void validate_number(char *s, Lisp_Object a, Lisp_Object b, Lisp_Object c)
{
int32_t la, w, msd;
if (!is_numbers(a)) return;
la = (length_of_header(numhdr(a))-CELL-4)/4;
if (la < 0)
{ trace_printf("%s: number with no digits (%.8x)\n", s, numhdr(a));
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
if (la == 0)
{ msd = bignum_digits(a)[0];
w = msd & fix_mask;
if (w == 0 || w == fix_mask)
{ trace_printf("%s: %.8x should be fixnum\n", s, msd);
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
if (signed_overflow(msd))
{ trace_printf("%s: %.8x should be two-word\n", s, msd);
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
return;
}
msd = bignum_digits(a)[la];
if (signed_overflow(msd))
{ trace_printf("%s: %.8x should be longer\n", s, msd);
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
if (msd == 0 && ((msd = bignum_digits(a)[la-1]) & 0x40000000) == 0)
{ trace_printf("%s: 0: %.8x should be shorter\n", s, msd);
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
if (msd == -1 && ((msd = bignum_digits(a)[la-1]) & 0x40000000) != 0)
{ trace_printf("%s: -1: %.8x should be shorter\n", s, msd);
if (is_number(b)) prin_to_trace(b), trace_printf("\n");
if (is_number(c)) prin_to_trace(c), trace_printf("\n");
my_exit(EXIT_FAILURE);
}
}
Lisp_Object plus2(Lisp_Object a, Lisp_Object b)
/*
* I probably want to change the specification of plus2 so that the fixnum +
* fixnum case is always expected to be done before the main body of the code
* is entered. Well maybe even if I do that it then costs very little to
* include the fixnum code here as well, so I will not delete it.
*/
{
switch ((int)a & TAG_BITS)
{
case TAG_FIXNUM:
switch ((int)b & TAG_BITS)
{
case TAG_FIXNUM:
/*
* This is where fixnum + fixnum arithmetic happens - the case I most want to
* make efficient.
*/
{ int32_t r = int_of_fixnum(a) + int_of_fixnum(b);
int32_t t = r & fix_mask;
if (t == 0 || t == fix_mask) return fixnum_of_int(r);
else return make_one_word_bignum(r);
}
#ifdef COMMON
case TAG_SFLOAT:
return plusis(a, b);
#endif
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return plusib(a, b);
#ifdef COMMON
case TYPE_RATNUM:
return plusir(a, b);
case TYPE_COMPLEX_NUM:
return plusic(a, b);
#endif
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return plusif(a, b);
default:
return aerror1("bad arg for plus", b);
}
#ifdef COMMON
case TAG_SFLOAT:
switch (b & TAG_BITS)
{
case TAG_FIXNUM:
return plussi(a, b);
case TAG_SFLOAT:
{ Float_union aa, bb;
aa.i = a - TAG_SFLOAT;
bb.i = b - TAG_SFLOAT;
aa.f = (float)(aa.f + bb.f);
return (aa.i & ~(int32_t)0xf) + TAG_SFLOAT;
}
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return plussb(a, b);
case TYPE_RATNUM:
return plussr(a, b);
case TYPE_COMPLEX_NUM:
return plussc(a, b);
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return plussf(a, b);
default:
return aerror1("bad arg for plus", b);
}
#endif
case TAG_NUMBERS:
{ int32_t ha = type_of_header(numhdr(a));
switch (ha)
{
case TYPE_BIGNUM:
switch ((int)b & TAG_BITS)
{
case TAG_FIXNUM:
return plusbi(a, b);
#ifdef COMMON
case TAG_SFLOAT:
return plusbs(a, b);
#endif
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return plusbb(a, b);
#ifdef COMMON
case TYPE_RATNUM:
return plusbr(a, b);
case TYPE_COMPLEX_NUM:
return plusbc(a, b);
#endif
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return plusbf(a, b);
default:
return aerror1("bad arg for plus", b);
}
#ifdef COMMON
case TYPE_RATNUM:
switch (b & TAG_BITS)
{
case TAG_FIXNUM:
return plusri(a, b);
case TAG_SFLOAT:
return plusrs(a, b);
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return plusrb(a, b);
case TYPE_RATNUM:
return plusrr(a, b);
case TYPE_COMPLEX_NUM:
return plusrc(a, b);
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return plusrf(a, b);
default:
return aerror1("bad arg for plus", b);
}
case TYPE_COMPLEX_NUM:
switch (b & TAG_BITS)
{
case TAG_FIXNUM:
return plusci(a, b);
case TAG_SFLOAT:
return pluscs(a, b);
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return pluscb(a, b);
case TYPE_RATNUM:
return pluscr(a, b);
case TYPE_COMPLEX_NUM:
return pluscc(a, b);
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return pluscf(a, b);
default:
return aerror1("bad arg for plus", b);
}
#endif
default: return aerror1("bad arg for plus", a);
}
}
case TAG_BOXFLOAT:
switch ((int)b & TAG_BITS)
{
case TAG_FIXNUM:
return plusfi(a, b);
#ifdef COMMON
case TAG_SFLOAT:
return plusfs(a, b);
#endif
case TAG_NUMBERS:
{ int32_t hb = type_of_header(numhdr(b));
switch (hb)
{
case TYPE_BIGNUM:
return plusfb(a, b);
#ifdef COMMON
case TYPE_RATNUM:
return plusfr(a, b);
case TYPE_COMPLEX_NUM:
return plusfc(a, b);
#endif
default:
return aerror1("bad arg for plus", b);
}
}
case TAG_BOXFLOAT:
return plusff(a, b);
default:
return aerror1("bad arg for plus", b);
}
default:
return aerror1("bad arg for plus", a);
}
}
Lisp_Object difference2(Lisp_Object a, Lisp_Object b)
{
Lisp_Object nil;
switch ((int)b & TAG_BITS)
{
case TAG_FIXNUM:
if (is_fixnum(a))
{
int32_t r = int_of_fixnum(a) - int_of_fixnum(b);
int32_t t = r & fix_mask;
if (t == 0 || t == fix_mask) return fixnum_of_int(r);
else return make_one_word_bignum(r);
}
else if (b != ~0x7ffffffe) return plus2(a, 2*TAG_FIXNUM-b);
else
{ push(a);
b = make_one_word_bignum(-int_of_fixnum(b));
break;
}
case TAG_NUMBERS:
push(a);
if (type_of_header(numhdr(b)) == TYPE_BIGNUM) b = negateb(b);
else b = negate(b);
break;
case TAG_BOXFLOAT:
default:
push(a);
b = negate(b);
break;
}
pop(a);
errexit();
return plus2(a, b);
}
Lisp_Object add1(Lisp_Object p)
/*
* Increment a number. Short cut when the number is a fixnum, otherwise
* just hand over to the general addition code.
*/
{
if (is_fixnum(p))
{ if (p == 0x7ffffff1) /* The ONLY possible overflow case here */
return make_one_word_bignum(0x08000000);
else return (Lisp_Object)(p + 0x10);
}
else return plus2(p, fixnum_of_int(1));
}
Lisp_Object sub1(Lisp_Object p)
/*
* Decrement a number. Short cut when the number is a fixnum, otherwise
* just hand over to the general addition code.
*/
{
if (is_fixnum(p))
{ if (p == ~0x7ffffffe) /* The ONLY possible overflow case here */
return make_one_word_bignum(int_of_fixnum(p) - 1);
else return (Lisp_Object)(p - 0x10);
}
else return plus2(p, fixnum_of_int(-1));
}
/* end of arith01.c */