ikarus/src/ikarus-numerics.c

1582 lines
47 KiB
C

/*
* Ikarus Scheme -- A compiler for R6RS Scheme.
* Copyright (C) 2006,2007 Abdulaziz Ghuloum
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program 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 <http://www.gnu.org/licenses/>.
*/
#include "ikarus-data.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <gmp.h>
#define most_positive_fixnum 0x1FFFFFFF
#define most_negative_fixnum 0x20000000
#define max_digits_per_limb 10
#ifdef NDEBUG
#define verify_bignum(x,caller) (x)
#else
static ikp
verify_bignum(ikp x, char* caller){
if(tagof(x) != vector_tag){
fprintf(stderr, "Error in (%s) invalid primary tag %p\n", caller, x);
exit(-1);
}
ikp fst = ref(x, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
if(limb_count <= 0){
fprintf(stderr,
"Error in (%s) invalid limb count in fst=0x%08x\n",
caller, (int)fst);
exit(-1);
}
int pos;
if((int)fst & bignum_sign_mask){
pos = 0;
} else {
pos = 1;
}
unsigned int last_limb =
(unsigned int) ref(x, off_bignum_data + (limb_count - 1) * wordsize);
if(last_limb == 0){
fprintf(stderr,
"Error in (%s) invalid last limb = 0x%08x", caller, last_limb);
exit(-1);
}
if(limb_count == 1){
if(pos){
if(last_limb <= most_positive_fixnum){
fprintf(stderr,
"Error in (%s) should be a positive fixnum: 0x%08x\n",
caller, last_limb);
exit(-1);
}
} else {
if(last_limb <= most_negative_fixnum){
fprintf(stderr,
"Error in (%s) should be a negative fixnum: 0x%08x\n",
caller, last_limb);
exit(-1);
}
}
}
/* ok */
return x;
}
#endif
#define BN(x) verify_bignum(x,"BN")
#if 0
ikp
ikrt_isbignum(ikp x){
if(tagof(x) == vector_tag){
ikp fst = ref(x, -vector_tag);
if (bignum_tag == (bignum_mask & (int)fst)){
return true_object;
}
}
return false_object;
}
#endif
ikp
ikrt_positive_bn(ikp x){
ikp fst = ref(x, -vector_tag);
if((int)fst & bignum_sign_mask){
return false_object;
} else {
return true_object;
}
}
ikp
ikrt_even_bn(ikp x){
int fst = (int)ref(x, wordsize-vector_tag);
if(fst & 1){
return false_object;
} else {
return true_object;
}
}
ikp
ikrt_fxfxplus(ikp x, ikp y, ikpcb* pcb){
int n1 = unfix(x);
int n2 = unfix(y);
int r = n1 + n2;
ikp q = fix(r);
if(r == unfix(q)){
return q;
}
else {
ikp bn = ik_alloc(pcb, align(disp_bignum_data + wordsize));
if(r > 0){
ref(bn, 0) = (ikp)(bignum_tag | (1 << bignum_length_shift));
ref(bn, disp_bignum_data) = (ikp)r;
}
else {
ref(bn, 0) =
(ikp)(bignum_tag |
(1 << bignum_length_shift) |
(1 << bignum_sign_shift));
ref(bn, disp_bignum_data) = (ikp)-r;
}
return verify_bignum(bn+vector_tag, "fxfx+");
}
}
ikp
ikrt_fxbnplus(ikp x, ikp y, ikpcb* pcb){
if(x == 0){ return y ; }
ikp fst = ref(y, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
int intx = unfix(x);
if(intx > 0){
if((bignum_sign_mask & (int)fst) == 0){
/* positive fx + positive bn = even bigger positive */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
intx);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+1");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+2");
}
}
else {
//fprintf(stderr, "this case 0x%08x\n", intx);
/* positive fx + negative bn = smaller negative bn */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
intx);
if(borrow){
fprintf(stderr, "Error: BUG in borrow1 %d\n", borrow);
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize))
? limb_count
: (limb_count - 1);
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_negative_fixnum){
return fix(-(int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+3");
}
}
else {
if((bignum_sign_mask & (int)fst) == 0){
/* negative fx + positive bn = smaller positive */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
- intx);
if(borrow){
fprintf(stderr, "Error: BUG in borrow2\n");
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize) == 0)
? (limb_count - 1)
: limb_count;
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_positive_fixnum){
return fix((int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+4");
} else {
/* negative fx + negative bn = larger negative */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
-intx);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+5");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn+5");
}
}
}
}
ikp
ikrt_bnbnplus(ikp x, ikp y, ikpcb* pcb){
unsigned int xfst = (unsigned int)ref(x, -vector_tag);
unsigned int yfst = (unsigned int)ref(y, -vector_tag);
int xsign = xfst & bignum_sign_mask;
int ysign = yfst & bignum_sign_mask;
int xlimbs = xfst >> bignum_length_shift;
int ylimbs = yfst >> bignum_length_shift;
if(xsign == ysign){
int n1,n2;
ikp s1,s2;
if(xlimbs > ylimbs){
n1 = xlimbs; n2 = ylimbs; s1 = x; s2 = y;
} else {
n1 = ylimbs; n2 = xlimbs; s1 = y; s2 = x;
}
ikp res = ik_alloc(pcb, align(disp_bignum_data + (n1+1)*wordsize));
mp_limb_t carry = mpn_add((mp_limb_t*) (res+disp_bignum_data),
(mp_limb_t*) (s1-vector_tag+disp_bignum_data),
n1,
(mp_limb_t*) (s2-vector_tag+disp_bignum_data),
n2);
if(carry){
ref(res, disp_vector_data + xlimbs*wordsize) = (ikp)1;
ref(res, 0) = (ikp)
(((n1+1) << bignum_length_shift) |
xsign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn+1");
} else {
ref(res, 0) = (ikp)
((n1 << bignum_length_shift) |
xsign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn+2");
}
}
else {
ikp s1=x, s2=y;
int n1=xlimbs, n2=ylimbs;
int result_sign = xsign;
while((xlimbs == ylimbs) &&
(ref(x, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize) ==
ref(y, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize))){
xlimbs -= 1;
ylimbs -= 1;
if(xlimbs == 0){ return 0; }
}
/* |x| != |y| */
if(xlimbs <= ylimbs){
if(xlimbs == ylimbs){
if((ref(y, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize) >
ref(x, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize))){
s1 = y; n1 = ylimbs;
s2 = x; n2 = xlimbs;
result_sign = ysign;
}
} else {
s1 = y; n1 = ylimbs;
s2 = x; n2 = xlimbs;
result_sign = ysign;
}
}
/* |s1| > |s2| */
ikp res = ik_alloc(pcb, align(disp_bignum_data + n1 * wordsize));
int burrow = mpn_sub((mp_limb_t*) (res + disp_bignum_data),
(mp_limb_t*) (s1 - vector_tag + disp_bignum_data),
n1,
(mp_limb_t*) (s2 - vector_tag + disp_bignum_data),
n2);
if(burrow){
fprintf(stderr, "BUG: Burrow error in bnbn+\n");
exit(-1);
}
int len = n1;
while(ref(res, disp_bignum_data + (len-1)*wordsize) == 0){
len--;
if(len == 0){
return 0;
}
}
if(result_sign == 0){
/* positive result */
if(len == 1){
unsigned int fst_limb = (unsigned int) ref(res, disp_bignum_data);
if(fst_limb <= most_positive_fixnum){
return fix((int)fst_limb);
}
}
ref(res, 0) = (ikp)
((len << bignum_length_shift) |
result_sign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn+3");
} else {
/* negative result */
if(len == 1){
unsigned int fst_limb = (unsigned int) ref(res, disp_bignum_data);
if(fst_limb <= most_negative_fixnum){
return fix(-(int)fst_limb);
}
}
ref(res, 0) = (ikp)
((len << bignum_length_shift) |
result_sign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn+4");
}
}
}
ikp
ikrt_fxfxminus(ikp x, ikp y, ikpcb* pcb){
int n1 = unfix(x);
int n2 = unfix(y);
int r = n1 - n2;
if(r >= 0){
if(((unsigned int)r) <= most_positive_fixnum){
return fix(r);
} else {
ikp bn = ik_alloc(pcb, align(disp_bignum_data + wordsize));
ref(bn, 0) = (ikp) (bignum_tag | (1 << bignum_length_shift));
ref(bn, disp_bignum_data) = (ikp)r;
return verify_bignum(bn+vector_tag,"fxfx-1");
}
} else {
ikp fxr = fix(r);
if(unfix(fxr) == r){
return fxr;
} else {
ikp bn = ik_alloc(pcb, align(disp_bignum_data + wordsize));
ref(bn, 0) = (ikp)
(bignum_tag |
(1 << bignum_sign_shift) |
(1 << bignum_length_shift));
ref(bn, disp_bignum_data) = (ikp)(-r);
return verify_bignum(bn+vector_tag, "fxfx-2");
}
}
}
ikp
ikrt_bnnegate(ikp x, ikpcb* pcb){
ikp fst = ref(x, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
if(limb_count == 1){
if((bignum_sign_mask & (int)fst) == 0){
/* positive bignum */
unsigned int limb = (unsigned int) ref(x, disp_bignum_data - vector_tag);
if(limb == (most_positive_fixnum + 1)){
return fix(-(int)limb);
}
}
}
ikp bn = ik_alloc(pcb, align(disp_bignum_data + limb_count * wordsize));
memcpy(bn+disp_bignum_data,
x-vector_tag+disp_bignum_data,
limb_count*wordsize);
ref(bn, 0) = (ikp)
(bignum_tag |
((1 << bignum_sign_shift) - (bignum_sign_mask & (int)fst)) |
(limb_count << bignum_length_shift));
return verify_bignum(bn+vector_tag, "bnneg");
}
ikp
ikrt_fxbnminus(ikp x, ikp y, ikpcb* pcb){
if(x == 0){ return ikrt_bnnegate(y, pcb) ; }
ikp fst = ref(y, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
int intx = unfix(x);
if(intx > 0){
if(bignum_sign_mask & (int)fst){
/* positive fx - negative bn = positive bn */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
intx);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn-1");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn-2");
}
}
else {
/* positive fx - positive bn = smaller negative bn/fx */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
intx);
if(borrow){
fprintf(stderr, "Error: BUG in borrow3\n");
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize))
? limb_count
: (limb_count - 1);
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_negative_fixnum){
return fix(-(int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn-");
}
}
else {
if(bignum_sign_mask & (int)fst){
/* negative fx - negative bn = smaller positive */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
- intx);
if(borrow){
fprintf(stderr, "Error: BUG in borrow4\n");
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize) == 0)
? (limb_count - 1)
: limb_count;
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_positive_fixnum){
return fix((int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag,"fxbn-");
} else {
/* negative fx - positive bn = larger negative */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y - vector_tag + disp_bignum_data),
limb_count,
-intx);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn-");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "fxbn-");
}
}
}
}
ikp
ikrt_bnfxminus(ikp x, ikp y, ikpcb* pcb){
if(y == 0){ return x; }
ikp fst = ref(x, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
int inty = unfix(y);
if(inty < 0){
if((bignum_sign_mask & (int)fst) == 0){
/* - negative fx + positive bn = positive bn */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(x - vector_tag + disp_bignum_data),
limb_count,
-inty);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag,"bnfx-");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag,"bnfx-");
}
}
else {
/* - negative fx + negative bn = smaller negative bn/fx */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(x - vector_tag + disp_bignum_data),
limb_count,
-inty);
if(borrow){
fprintf(stderr, "Error: BUG in borrow5\n");
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize))
? limb_count
: (limb_count - 1);
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_negative_fixnum){
return fix(-(int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag,"bnfx-");
}
}
else {
if((bignum_sign_mask & (int)fst) == 0){
/* - positive fx + positive bn = smaller positive */
ikp r = ik_alloc(pcb, align(disp_bignum_data+limb_count*wordsize));
int borrow = mpn_sub_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(x - vector_tag + disp_bignum_data),
limb_count,
inty);
if(borrow){
fprintf(stderr, "Error: BUG in borrow6\n");
exit(-1);
}
int result_size =
(ref(r, disp_bignum_data + (limb_count-1)*wordsize) == 0)
? (limb_count - 1)
: limb_count;
if(result_size == 0){
return 0;
}
if(result_size == 1){
unsigned int last =
(unsigned int) ref(r, disp_bignum_data + (result_size-1)*wordsize);
if(last <= most_positive_fixnum){
return fix((int)last);
}
}
ref(r, 0) = (ikp)
((result_size << bignum_length_shift) |
(0 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "bnfx-");
} else {
/* - positive fx + negative bn = larger negative */
ikp r = ik_alloc(pcb, align(disp_bignum_data+(limb_count+1)*wordsize));
int carry = mpn_add_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(x - vector_tag + disp_bignum_data),
limb_count,
inty);
if(carry){
ref(r, disp_bignum_data + limb_count*wordsize) = (ikp)1;
ref(r, 0) = (ikp)
(((limb_count + 1) << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "bnfx-");
} else {
ref(r, 0) = (ikp)
((limb_count << bignum_length_shift) |
(1 << bignum_sign_shift) |
bignum_tag);
return verify_bignum(r+vector_tag, "bnfx-");
}
}
}
}
ikp
ikrt_bnbnminus(ikp x, ikp y, ikpcb* pcb){
if(x == y) { return 0; }
unsigned int xfst = (unsigned int)ref(x, -vector_tag);
unsigned int yfst = (unsigned int)ref(y, -vector_tag);
int xsign = xfst & bignum_sign_mask;
int ysign = yfst & bignum_sign_mask;
int xlimbs = xfst >> bignum_length_shift;
int ylimbs = yfst >> bignum_length_shift;
if(xsign != ysign){
int n1,n2;
ikp s1,s2;
if(xlimbs >= ylimbs){
n1 = xlimbs; n2 = ylimbs; s1 = x; s2 = y;
} else {
n1 = ylimbs; n2 = xlimbs; s1 = y; s2 = x;
}
ikp res = ik_alloc(pcb, align(disp_bignum_data + (n1+1)*wordsize));
mp_limb_t carry = mpn_add((mp_limb_t*) (res+disp_bignum_data),
(mp_limb_t*) (s1-vector_tag+disp_bignum_data),
n1,
(mp_limb_t*) (s2-vector_tag+disp_bignum_data),
n2);
if(carry){
ref(res, disp_vector_data + xlimbs*wordsize) = (ikp)1;
ref(res, 0) = (ikp)
(((n1+1) << bignum_length_shift) |
xsign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn-");
} else {
ref(res, 0) = (ikp)
((n1 << bignum_length_shift) |
xsign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn-");
}
}
else {
/* same sign */
if(xlimbs == ylimbs){
while((ref(x, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize) ==
ref(y, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize))){
xlimbs -= 1;
if(xlimbs == 0){ return 0; }
}
ylimbs = xlimbs;
}
ikp s1=x, s2=y;
int n1=xlimbs, n2=ylimbs;
int result_sign = xsign;
/* |x| != |y| */
if(xlimbs <= ylimbs){
if(xlimbs == ylimbs){
if((ref(y, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize) >
ref(x, -vector_tag+disp_bignum_data+(xlimbs-1)*wordsize))){
s1 = y; n1 = ylimbs;
s2 = x; n2 = xlimbs;
result_sign = (1 << bignum_sign_shift) - ysign;
}
} else {
s1 = y; n1 = ylimbs;
s2 = x; n2 = xlimbs;
result_sign = (1 << bignum_sign_shift) - ysign;
}
}
/* |s1| > |s2| */
ikp res = ik_alloc(pcb, align(disp_bignum_data + n1 * wordsize));
int burrow = mpn_sub((mp_limb_t*) (res + disp_bignum_data),
(mp_limb_t*) (s1 - vector_tag + disp_bignum_data),
n1,
(mp_limb_t*) (s2 - vector_tag + disp_bignum_data),
n2);
if(burrow){
fprintf(stderr, "BUG: Burrow error in bnbn-\n");
exit(-1);
}
int len = n1;
while(ref(res, disp_bignum_data + (len-1)*wordsize) == 0){
len--;
if(len == 0){
return 0;
}
}
if(result_sign == 0){
/* positive result */
if(len == 1){
unsigned int fst_limb = (unsigned int) ref(res, disp_bignum_data);
if(fst_limb <= most_positive_fixnum){
return fix((int)fst_limb);
}
}
ref(res, 0) = (ikp)
((len << bignum_length_shift) |
result_sign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn-");
} else {
/* negative result */
if(len == 1){
unsigned int fst_limb = (unsigned int) ref(res, disp_bignum_data);
if(fst_limb <= most_negative_fixnum){
return fix(-(int)fst_limb);
}
}
ref(res, 0) = (ikp)
((len << bignum_length_shift) |
result_sign |
bignum_tag);
return verify_bignum(res+vector_tag, "bnbn-");
}
}
}
ikp
ikrt_fxfxmult(ikp x, ikp y, ikpcb* pcb){
int n1 = unfix(x);
int n2 = unfix(y);
mp_limb_t lo = 0;
mp_limb_t s1 = n1;
mp_limb_t s2 = n2;
int sign = 0;
if(n1 < 0){
s1 = -n1;
sign = 1 - sign;
}
if(n2 < 0){
s2 = -n2;
sign = 1 - sign;
}
mp_limb_t hi = mpn_mul_1(&lo, &s1, 1, s2);
if(hi == 0){
if(sign){
if(lo <= most_negative_fixnum){
return fix(-((int)lo));
}
} else {
if(lo <= most_positive_fixnum){
return fix((int)lo);
}
}
ikp r = ik_alloc(pcb, disp_bignum_data + wordsize);
ref(r, 0) = (ikp)
(bignum_tag |
(sign << bignum_sign_shift) |
(1 << bignum_length_shift));
ref(r, disp_bignum_data) = (ikp)lo;
return BN(r+vector_tag);
} else {
ikp r = ik_alloc(pcb, align(disp_bignum_data + 2*wordsize));
ref(r, 0) = (ikp)
(bignum_tag |
(sign << bignum_sign_shift) |
(2 << bignum_length_shift));
ref(r, disp_bignum_data) = (ikp)lo;
ref(r, disp_bignum_data+wordsize) = (ikp)hi;
return BN(r+vector_tag);
}
}
ikp
normalize_bignum(int limbs, int sign, ikp r){
while(ref(r, disp_bignum_data + (limbs-1)*wordsize) == 0){
limbs--;
if(limbs == 0){ return 0;}
}
if(limbs == 1){
unsigned int last = (unsigned int) ref(r, disp_bignum_data);
if(sign == 0){
if(last <= most_positive_fixnum){
return fix((int)last);
}
} else {
if(last <= most_negative_fixnum){
return fix(-((int)last));
}
}
}
ref(r, 0) = (ikp) (bignum_tag | sign | (limbs << bignum_length_shift));
return BN(r+vector_tag);
}
ikp
ikrt_fxbnmult(ikp x, ikp y, ikpcb* pcb){
int n2 = unfix(x);
if(n2 == 0) { return 0; }
mp_limb_t s2 = (n2>0) ? n2 : (- n2);
ikp fst = ref(y, -vector_tag);
int limb_count = ((unsigned int) fst) >> bignum_length_shift;
ikp r = ik_alloc(pcb, align(disp_bignum_data + (limb_count+1)*wordsize));
mp_limb_t hi = mpn_mul_1((mp_limb_t*)(r+disp_bignum_data),
(mp_limb_t*)(y-vector_tag+disp_bignum_data),
limb_count,
s2);
ref(r, disp_bignum_data + limb_count * wordsize) = (ikp)hi;
int sign =
((n2 > 0) ?
(bignum_sign_mask & (int)fst) :
((1 << bignum_sign_shift) - (bignum_sign_mask&(int)fst)));
return normalize_bignum(limb_count+1, sign, r);
}
ikp
ikrt_bnbnmult(ikp x, ikp y, ikpcb* pcb){
int f1 = (int)ref(x, -vector_tag);
int f2 = (int)ref(y, -vector_tag);
int n1 = ((unsigned int)f1) >> bignum_length_shift;
int n2 = ((unsigned int)f2) >> bignum_length_shift;
int nr = n1 + n2;
ikp bn = ik_alloc(pcb, align(disp_bignum_data + nr*wordsize));
mp_limb_t r;
if(n1 >= n2){
r = mpn_mul((mp_limb_t*)(bn+disp_bignum_data),
(mp_limb_t*)(x-vector_tag+disp_bignum_data),
n1,
(mp_limb_t*)(y-vector_tag+disp_bignum_data),
n2);
} else {
r = mpn_mul((mp_limb_t*)(bn+disp_bignum_data),
(mp_limb_t*)(y-vector_tag+disp_bignum_data),
n2,
(mp_limb_t*)(x-vector_tag+disp_bignum_data),
n1);
}
int sign =
((bignum_sign_mask & f1) ?
((1 << bignum_sign_shift) - (bignum_sign_mask & f2)) :
(bignum_sign_mask & f2));
return normalize_bignum(nr, sign, bn);
}
ikp
ikrt_bnbncomp(ikp bn1, ikp bn2){
ikp f1 = ref(bn1, -vector_tag);
ikp f2 = ref(bn2, -vector_tag);
if(bignum_sign_mask & (int)f1){
if(bignum_sign_mask & (int)f2){
/* both negative */
int n1 = ((unsigned int) f1) >> bignum_length_shift;
int n2 = ((unsigned int) f2) >> bignum_length_shift;
if(n1 < n2) {
return fix(1);
} else if(n1 > n2){
return fix(-1);
} else {
int i;
for(i=(n1-1); i>=0; i--){
unsigned int t1 =
(unsigned int) ref(bn1,disp_bignum_data-vector_tag+i*wordsize);
unsigned int t2 =
(unsigned int) ref(bn2,disp_bignum_data-vector_tag+i*wordsize);
if(t1 < t2){
return fix(1);
} else if(t1 > t2){
return fix(-1);
}
}
}
return 0;
} else {
/* n1 negative, n2 positive */
return fix(-1);
}
} else {
if(bignum_sign_mask & (int)f2){
/* n1 positive, n2 negative */
return fix(1);
} else {
/* both positive */
int n1 = ((unsigned int) f1) >> bignum_length_shift;
int n2 = ((unsigned int) f2) >> bignum_length_shift;
if(n1 < n2) {
return fix(-1);
} else if(n1 > n2){
return fix(1);
} else {
int i;
for(i=(n1-1); i>=0; i--){
unsigned int t1 =
(unsigned int) ref(bn1,disp_bignum_data-vector_tag+i*wordsize);
unsigned int t2 =
(unsigned int) ref(bn2,disp_bignum_data-vector_tag+i*wordsize);
if(t1 < t2){
return fix(-1);
} else if(t1 > t2){
return fix(1);
}
}
}
return 0;
}
}
}
/* FIXME: Too complicated! */
ikp
ikrt_fxbnlogand(ikp x, ikp y, ikpcb* pcb){
int n1 = unfix(x);
ikp fst = ref(y, -vector_tag);
if(n1 >= 0){
if(bignum_sign_mask & (unsigned int) fst){
/* y is negative */
return fix(n1 & (1+~(int)ref(y, disp_vector_data-vector_tag)));
} else {
/* y is positive */
return fix(n1 & (int)ref(y, disp_vector_data-vector_tag));
}
} else {
if(n1 == -1){ return y; }
if(bignum_sign_mask & (unsigned int) fst){
/* y is negative */
int len = (((unsigned int) fst) >> bignum_length_shift);
unsigned int nn =
(1+~((1+~(int)ref(y, disp_bignum_data - vector_tag)) & n1));
if((len == 1) && (nn <= most_negative_fixnum)){
return fix(-nn);
}
ikp r = ik_alloc(pcb, align(disp_bignum_data + len * wordsize));
ref(r, 0) = fst;
ref(r, disp_bignum_data) = (ikp) nn;
int i;
for(i=1; i<len; i++){
ref(r, disp_bignum_data+i*wordsize) =
ref(y, disp_bignum_data-vector_tag+i*wordsize);
}
return BN(r+vector_tag);
} else {
/* y is positive */
int len = (((unsigned int) fst) >> bignum_length_shift);
ikp r = ik_alloc(pcb, align(disp_bignum_data + len * wordsize));
ref(r, 0) = fst;
ref(r, disp_bignum_data) = (ikp)
(((int)ref(y, disp_bignum_data - vector_tag)) & n1);
int i;
for(i=1; i<len; i++){
ref(r, disp_bignum_data+i*wordsize) =
ref(y, disp_bignum_data-vector_tag+i*wordsize);
}
return BN(r+vector_tag);
}
}
}
static inline int
count_leading_ffs(int n, unsigned int* x){
int idx;
for(idx=0; idx<n; idx++){
if(x[idx] != -1){
return idx;
}
}
return n;
}
static void
bits_compliment(unsigned int* src, unsigned int* dst, int n){
int carry = 1;
int i;
for(i=0; i<n; i++){
unsigned int d = src[i];
unsigned int c = carry + ~ d;
dst[i] = c;
carry = (carry && ! d);
}
}
static void
bits_compliment_with_carry(unsigned int* src, unsigned int* dst, int
n, int carry){
int i;
for(i=0; i<n; i++){
unsigned int d = src[i];
unsigned int c = carry + ~ d;
dst[i] = c;
carry = (carry && ! d);
}
}
static void
bits_compliment_logand(unsigned int* s1, unsigned int* s2, unsigned int* dst, int n){
int carry = 1;
int i;
for(i=0; i<n; i++){
unsigned int d = s1[i];
unsigned int c = carry + ~ d;
dst[i] = c & s2[i];
carry = (carry && ! d);
}
}
static int
bits_carry(unsigned int* s, int n){
/*
int carry = 1;
int i;
for(i=0; i<n; i++){
unsigned int d = s[i];
carry = (carry && ! d);
}
return carry;
*/
int i;
for(i=0; i<n; i++){
if (s[i] != 0){
return 0;
}
}
return 1;
}
ikp
ikrt_bnlognot(ikp x, ikpcb* pcb){
ikp fst = ref(x, -vector_tag);
int n = ((unsigned int)fst) >> bignum_length_shift;
unsigned int* s1 = ((unsigned int*)(x+disp_bignum_data-vector_tag));
if(bignum_sign_mask & (unsigned int) fst){
/* negative */
ikp r = ik_alloc(pcb, align(disp_bignum_data + n*wordsize));
unsigned int* rd = (unsigned int*)(r+disp_bignum_data);
int i;
for(i=0; (i<n) && (s1[i] == 0); i++) {
rd[i] = -1;
}
rd[i] = s1[i] - 1;
for(i++; i<n; i++){
rd[i] = s1[i];
}
return normalize_bignum(n, 0, r);
} else {
/* positive */
int i;
for(i=0; (i<n) && (s1[i] == -1); i++) {/*nothing*/}
if(i==n){
ikp r = ik_alloc(pcb, align(disp_bignum_data + (n+1)*wordsize));
bzero(r+disp_bignum_data, n*wordsize);
((unsigned int*)(r+disp_bignum_data))[n] = 1;
ref(r, 0) = (ikp)
(bignum_tag | (1<<bignum_sign_shift) | ((n+1) << bignum_length_shift));
return r+vector_tag;
} else {
ikp r = ik_alloc(pcb, align(disp_bignum_data + n*wordsize));
unsigned int* rd = (unsigned int*)(r+disp_bignum_data);
int j;
for(j=0; j<i; j++){ rd[j] = 0; }
rd[i] = s1[i] + 1;
for(j=i+1; j<n; j++){ rd[j] = s1[j]; }
ref(r, 0) = (ikp)
(bignum_tag | (1<<bignum_sign_shift) | (n << bignum_length_shift));
return r+vector_tag;
}
}
}
ikp
ikrt_bnbnlogand(ikp x, ikp y, ikpcb* pcb){
ikp xfst = ref(x, -vector_tag);
ikp yfst = ref(y, -vector_tag);
int n1 = ((unsigned int) xfst) >> bignum_length_shift;
int n2 = ((unsigned int) yfst) >> bignum_length_shift;
if(bignum_sign_mask & (unsigned int) xfst){
if(bignum_sign_mask & (unsigned int) yfst){
unsigned int* s1 = ((unsigned int*)(x+disp_bignum_data-vector_tag));
unsigned int* s2 = ((unsigned int*)(y+disp_bignum_data-vector_tag));
if(n1 >= n2){
ikp r = ik_alloc(pcb, align(disp_bignum_data + n1*wordsize));
unsigned int* s = ((unsigned int*)(r+disp_bignum_data));
bits_compliment(s1, s, n1);
bits_compliment_logand(s2, s, s, n2);
bits_compliment(s, s, n1);
return normalize_bignum(n1, 1<<bignum_sign_shift, r);
} else {
return ikrt_bnbnlogand(y,x,pcb);
}
} else {
return ikrt_bnbnlogand(y,x,pcb);
}
} else {
if(bignum_sign_mask & (unsigned int) yfst){
/* x positive, y negative */
/* the result is at most n1 words long */
unsigned int* s1 = ((unsigned int*)(x+disp_bignum_data-vector_tag));
unsigned int* s2 = ((unsigned int*)(y+disp_bignum_data-vector_tag));
ikp r = ik_alloc(pcb, align(disp_bignum_data + n1*wordsize));
unsigned int* s = ((unsigned int*)(r+disp_bignum_data));
bits_compliment_logand(s2, s1, s, n1);
return normalize_bignum(n1, 0, r);
} else {
/* both positive */
int n = (n1<n2)?n1:n2;
int i;
for(i=n-1; i>=0; i--){
int l1 =
(int) ref(x, disp_bignum_data-vector_tag+i*wordsize);
int l2 =
(int) ref(y, disp_bignum_data-vector_tag+i*wordsize);
int last = l1 & l2;
if(last){
if((i == 0) && (last < most_positive_fixnum)){
return fix(last);
}
ikp r = ik_alloc(pcb, align(disp_bignum_data+(i+1)*wordsize));
ref(r, 0) = (ikp) (bignum_tag | ((i+1)<<bignum_length_shift));
ref(r, disp_bignum_data + i*wordsize) = (ikp)last;
int j;
for(j=0; j<i; j++){
ref(r, disp_bignum_data + j*wordsize) = (ikp)
(((int)ref(x, disp_bignum_data-vector_tag+j*wordsize))
&
((int)ref(y, disp_bignum_data-vector_tag+j*wordsize)));
}
return r+vector_tag;
}
}
return 0;
}
}
}
static void
copy_bits_shifting_right(unsigned int* src, unsigned int* dst, int n, int m){
unsigned int carry = src[0] >> m;
int i;
for(i=1; i<n; i++){
unsigned int b = src[i];
dst[i-1] = (b << (32-m)) | carry;
carry = b >> m;
}
dst[n-1] = carry;
}
static void
copy_bits_shifting_left(unsigned int* src, unsigned int* dst, int n, int m){
unsigned int carry = 0;
int i;
for(i=0; i<n; i++){
unsigned int b = src[i];
dst[i] = (b << m) | carry;
carry = b >> (32-m);
}
dst[n] = carry;
}
ikp
ikrt_bignum_shift_right(ikp x, ikp y, ikpcb* pcb){
int m = unfix(y);
ikp fst = ref(x, -vector_tag);
int n = ((unsigned int) fst) >> bignum_length_shift;
int whole_limb_shift = m >> 5; /* FIXME: 5 are the bits in 32-bit num */
int bit_shift = m & 31;
int new_limb_count = n - whole_limb_shift;
if(bignum_sign_mask & (unsigned int) fst){
if(new_limb_count <= 0){
return fix(-1);
}
if(bit_shift == 0){
ikp r = ik_alloc(pcb, align(disp_bignum_data + new_limb_count * wordsize));
bits_compliment_with_carry(
(unsigned int*)(x+off_bignum_data+whole_limb_shift*wordsize),
(unsigned int*)(r+disp_bignum_data),
new_limb_count,
bits_carry((unsigned int*)(x+off_bignum_data), whole_limb_shift));
bits_compliment(
(unsigned int*)(r+disp_bignum_data),
(unsigned int*)(r+disp_bignum_data),
new_limb_count);
return normalize_bignum(new_limb_count, 1 << bignum_sign_shift, r);
} else {
ikp r = ik_alloc(pcb, align(disp_bignum_data + new_limb_count * wordsize));
bits_compliment_with_carry(
(unsigned int*)(x+off_bignum_data+whole_limb_shift*wordsize),
(unsigned int*)(r+disp_bignum_data),
new_limb_count,
bits_carry((unsigned int*)(x+off_bignum_data), whole_limb_shift));
copy_bits_shifting_right(
(unsigned int*)(r+disp_bignum_data),
(unsigned int*)(r+disp_bignum_data),
new_limb_count,
bit_shift);
*((unsigned int*)(r+disp_bignum_data+(new_limb_count-1)*wordsize))
|= (-1 << (32 - bit_shift));
bits_compliment(
(unsigned int*)(r+disp_bignum_data),
(unsigned int*)(r+disp_bignum_data),
new_limb_count);
return normalize_bignum(new_limb_count, 1 << bignum_sign_shift, r);
fprintf(stderr, "not yet for negative bignum_shift\n");
exit(-1);
}
} else {
if(new_limb_count <= 0){
return 0;
}
if(bit_shift == 0){
ikp r = ik_alloc(pcb, align(disp_bignum_data + new_limb_count * wordsize));
memcpy(r+disp_bignum_data,
x+off_bignum_data+whole_limb_shift*wordsize,
new_limb_count * wordsize);
return normalize_bignum(new_limb_count, 0, r);
} else {
ikp r = ik_alloc(pcb, align(disp_bignum_data + new_limb_count * wordsize));
copy_bits_shifting_right(
(unsigned int*)(x+off_bignum_data+whole_limb_shift*wordsize),
(unsigned int*)(r+disp_bignum_data),
new_limb_count,
bit_shift);
return normalize_bignum(new_limb_count, 0, r);
}
}
}
ikp
ikrt_fixnum_shift_left(ikp x, ikp y, ikpcb* pcb){
int m = unfix(y);
int n = unfix(x);
int limb_count = (m >> 5) + 2; /* FIXME: 5 are the bits in 32-bit num */
int bit_shift = m & 31;
ikp r = ik_alloc(pcb, align(disp_bignum_data + limb_count * wordsize));
unsigned int* s = (unsigned int*)(r+disp_bignum_data);
bzero(s, limb_count * wordsize);
if(n >= 0){
if(bit_shift){
s[limb_count-1] = n >> (32 - bit_shift);
}
s[limb_count-2] = n << bit_shift;
} else {
if(bit_shift){
s[limb_count-1] = (-n) >> (32 - bit_shift);
}
s[limb_count-2] = (-n) << bit_shift;
}
return normalize_bignum(limb_count, (n>=0)?(0):(1<<bignum_sign_shift), r);
}
ikp
ikrt_bignum_shift_left(ikp x, ikp y, ikpcb* pcb){
int m = unfix(y);
ikp fst = ref(x, -vector_tag);
int n = ((unsigned int) fst) >> bignum_length_shift;
int whole_limb_shift = m >> 5; /* FIXME: 5 are the bits in 32-bit num */
int bit_shift = m & 31;
if(bit_shift == 0){
int limb_count = n + whole_limb_shift;
ikp r = ik_alloc(pcb, align(disp_bignum_data + limb_count * wordsize));
unsigned int* s = (unsigned int*)(r+disp_bignum_data);
bzero(s, whole_limb_shift*wordsize);
memcpy(s+whole_limb_shift, x+off_bignum_data, n*wordsize);
return normalize_bignum(limb_count, (unsigned int)fst & bignum_sign_mask, r);
} else {
int limb_count = n + whole_limb_shift + 1;
ikp r = ik_alloc(pcb, align(disp_bignum_data + limb_count * wordsize));
unsigned int* s = (unsigned int*)(r+disp_bignum_data);
bzero(s, whole_limb_shift*wordsize);
copy_bits_shifting_left(
(unsigned int*)(x+off_bignum_data),
s+whole_limb_shift,
n,
bit_shift);
return normalize_bignum(limb_count, (unsigned int)fst & bignum_sign_mask, r);
}
}
#if 0
From TFM:
void
mpn_tdiv_qr (
mp limb t *qp, /* quotient placed here */
mp limb t *rp, /* remainder placed here */
mp size t qxn, /* must be zero! */
const mp limb t *np, /* first number */
mp size t nn, /* its length */
const mp limb t *dp, /* second number */
mp size t dn /* its length */
)
Divide {np, nn} by {dp, dn} and put the quotient at {qp,nn-dn+1}
and the remainder at {rp, dn}. The quotient is rounded towards 0.
No overlap is permitted between arguments. nn must be greater than
or equal to dn. The most significant limb of dp must be non-zero.
The qxn operand must be zero.
#endif
ikp
ikrt_bnbndivrem(ikp x, ikp y, ikpcb* pcb){
ikp xfst = ref(x, -vector_tag);
ikp yfst = ref(y, -vector_tag);
mp_size_t xn = ((unsigned int) xfst) >> bignum_length_shift;
mp_size_t yn = ((unsigned int) yfst) >> bignum_length_shift;
if(xn < yn){
/* quotient is zero, remainder is x */
ikp rv = ik_alloc(pcb, pair_size);
ref(rv, disp_car) = 0;
ref(rv, disp_cdr) = x;
return rv+pair_tag;
}
mp_size_t qn = xn - yn + 1;
mp_size_t rn = yn;
ikp q = ik_alloc(pcb, align(disp_bignum_data + qn*wordsize));
ikp r = ik_alloc(pcb, align(disp_bignum_data + rn*wordsize));
mpn_tdiv_qr (
(mp_limb_t*)(q+disp_bignum_data),
(mp_limb_t*)(r+disp_bignum_data),
0,
(mp_limb_t*)(x+off_bignum_data),
xn,
(mp_limb_t*)(y+off_bignum_data),
yn);
if(((unsigned int) xfst) & bignum_sign_mask){
/* x is negative => remainder is negative */
r = normalize_bignum(rn, 1 << bignum_sign_shift, r);
} else {
r = normalize_bignum(rn, 0, r);
}
if(((unsigned int) yfst) & bignum_sign_mask){
/* y is negative => quotient is opposite of x */
int sign =
bignum_sign_mask - (((unsigned int)xfst) & bignum_sign_mask);
q = normalize_bignum(qn, sign, q);
} else {
/* y is positive => quotient is same as x */
int sign = (((unsigned int)xfst) & bignum_sign_mask);
q = normalize_bignum(qn, sign, q);
}
ikp rv = ik_alloc(pcb, pair_size);
ref(rv, disp_car) = q;
ref(rv, disp_cdr) = r;
return rv+pair_tag;
}
#if 0
[Function]
mp_limb_t
mpn_divrem_1 (
mp limb t *r1p,
mp size t qxn,
mp limb t *s2p,
mp size t s2n,
mp limb t s3limb
)
Divide {s2p, s2n} by s3limb, and write the quotient at r1p. Return the remainder.
The integer quotient is written to {r1p+qxn, s2n} and in addition qxn fraction limbs are
developed and written to {r1p, qxn}. Either or both s2n and qxn can be zero. For most
usages, qxn will be zero.
#endif
ikp
ikrt_bnfxdivrem(ikp x, ikp y, ikpcb* pcb){
int yint = unfix(y);
mp_limb_t* s2p = (mp_limb_t*)(x+off_bignum_data);
ikp fst = ref(x, -vector_tag);
mp_size_t s2n = ((unsigned int) fst) >> bignum_length_shift;
ikp quot = ik_alloc(pcb,
align(s2n*wordsize + disp_bignum_data));
mp_limb_t rv = mpn_divrem_1(
(mp_limb_t*)(quot+disp_bignum_data),
0,
s2p,
s2n,
abs(yint));
ikp rem;
if(yint < 0){
/* y is negative => quotient is opposite of x */
int sign =
bignum_sign_mask - (((unsigned int)fst) & bignum_sign_mask);
quot = normalize_bignum(s2n, sign, quot);
} else {
/* y is positive => quotient is same as x */
int sign = (((unsigned int)fst) & bignum_sign_mask);
quot = normalize_bignum(s2n, sign, quot);
}
/* the remainder is always less than |y|, so it will
always be a fixnum. (if y == most_negative_fixnum,
then |remainder| will be at most most_positive_fixnum). */
if(((unsigned int) fst) & bignum_sign_mask){
/* x is negative => remainder is negative */
rem = (ikp) -(rv << fx_shift);
} else {
rem = fix(rv);
}
ikp p = ik_alloc(pcb, pair_size);
ref(p, disp_car) = quot;
ref(p, disp_cdr) = rem;
return p+pair_tag;
}
ikp
ikrt_bnfx_modulo(ikp x, ikp y, ikpcb* pcb){
int yint = unfix(y);
mp_limb_t* s2p = (mp_limb_t*)(x+off_bignum_data);
ikp fst = ref(x, -vector_tag);
mp_size_t s2n = ((unsigned int) fst) >> bignum_length_shift;
if(yint < 0){
if(((unsigned int) fst) & bignum_sign_mask){
/* x negative, y negative */
mp_limb_t m = mpn_mod_1(s2p, s2n, -yint);
return fix(-m);
} else {
/* x positive, y negative */
mp_limb_t m = mpn_mod_1(s2p, s2n, -yint);
return fix(yint+m);
}
} else {
if(((unsigned int) fst) & bignum_sign_mask){
/* x negative, y positive */
mp_limb_t m = mpn_mod_1(s2p, s2n, yint);
return fix(yint-m);
} else {
/* x positive, y positive */
mp_limb_t m = mpn_mod_1(s2p, s2n, yint);
return fix(m);
}
}
}
ikp
ikrt_bignum_to_bytevector(ikp x, ikpcb* pcb){
/* FIXME: avoid calling malloc, instead, use the heap pointer itself
* as a buffer to hold the temporary data after ensuring that it has enough
* space */
ikp fst = ref(x, -vector_tag);
int limb_count = (((unsigned int)fst) >> bignum_length_shift);
if(limb_count <= 0){
fprintf(stderr, "BUG: nbtostring: invalid length %d\n", limb_count);
exit(-1);
}
int sign_bit = bignum_sign_mask & (int) fst;
int nbsize = limb_count * sizeof(mp_limb_t);
int strsize = limb_count * max_digits_per_limb;
int mem_req = nbsize + strsize + 1;
unsigned char* mem = malloc(mem_req);
if(! mem){
fprintf(stderr, "Error allocating space for bignum\n");
exit(-1);
}
memcpy(mem, x - vector_tag + disp_bignum_data, nbsize);
mp_size_t bytes =
mpn_get_str(mem+nbsize, /* output string */
10, /* base */
(mp_limb_t*) mem, /* limb */
limb_count /* number of limbs */
);
unsigned char* string_start = mem + nbsize;
while(*string_start == 0){
string_start++;
bytes--;
}
ikp bv = ik_alloc(pcb, align(bytes + disp_bytevector_data + (sign_bit?1:0)));
ref(bv, 0) = fix(bytes + (sign_bit?1:0));
ikp dest = bv + disp_bytevector_data;
if(sign_bit){
*dest = '-';
dest++;
}
{
int i = 0;
while(i < bytes){
dest[i] = string_start[i] + '0';
i++;
}
dest[bytes] = 0;
}
free(mem);
return bv + bytevector_tag;
}
ikp
ikrt_fxrandom(ikp x){
int mask = 1;
int n = unfix(x);
{
while(mask < n){
mask = (mask << 1) | 1;
}
}
while(1){
long r = random() & mask;
if(r < n){
return fix(r);
}
}
}