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femtolisp/llt/bitvector-ops.c

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support reading hex float literals better text representation of infs and nans removing construction of low-level numeric types directly from strings adding hash function corresponding to equal better way to initialize builtins moving advanced bitvector ops to separate compilation unit rearranging hash table code so it can be specialized for different comparison functions one good way to bloat a piece of software is to add several ASCII pictures of the mona lisa
2008-11-23 02:12:37 -05:00
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include "dtypes.h"
#include "bitvector.h"
#ifdef WIN32
#include <malloc.h>
#define alloca _alloca
#endif
// greater than this # of words we use malloc instead of alloca
#define MALLOC_CUTOFF 2000
u_int32_t bitreverse(u_int32_t x)
{
u_int32_t m;
#ifdef __INTEL_COMPILER
x = _bswap(x);
#else
x = (x >> 16) | (x << 16); m = 0xff00ff00;
x = ((x & m) >> 8) | ((x & ~m) << 8);
#endif
m = 0xf0f0f0f0;
x = ((x & m) >> 4) | ((x & ~m) << 4); m = 0xcccccccc;
x = ((x & m) >> 2) | ((x & ~m) << 2); m = 0xaaaaaaaa;
x = ((x & m) >> 1) | ((x & ~m) << 1);
return x;
}
// shift all bits in a long bit vector
// n is # of int32s to consider, s is shift distance
// lowest bit-index is bit 0 of word 0
// TODO: handle boundary case of shift distance >= data size?
void bitvector_shr(u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_t i;
if (s == 0 || n == 0) return;
i = (s>>5);
if (i) {
n -= i;
memmove(b, &b[i], n*4);
memset(&b[n], 0, i*4);
s &= 31;
}
for(i=0; i < n-1; i++) {
b[i] = (b[i]>>s) | (b[i+1]<<(32-s));
}
b[i]>>=s;
}
// out-of-place version, good for re-aligning a strided submatrix to
// linear representation when a copy is needed
// assumes that dest has the same amount of space as source, even if it
// wouldn't have been necessary to hold the shifted bits
void bitvector_shr_to(u_int32_t *dest, u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_t i, j;
if (n == 0) return;
if (s == 0) {
memcpy(dest, b, n*4);
return;
}
j = (s>>5);
if (j) {
n -= j;
memset(&dest[n], 0, j*4);
s &= 31;
b = &b[j];
}
for(i=0; i < n-1; i++) {
dest[i] = (b[i]>>s) | (b[i+1]<<(32-s));
}
dest[i] = b[i]>>s;
}
void bitvector_shl(u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_t i, scrap=0, temp;
if (s == 0 || n == 0) return;
i = (s>>5);
if (i) {
n -= i;
memmove(&b[i], b, n*4);
memset(b, 0, i*4);
s &= 31;
b = &b[i];
}
for(i=0; i < n; i++) {
temp = (b[i]<<s) | scrap;
scrap = b[i]>>(32-s);
b[i] = temp;
}
}
// if dest has more space than source, set scrap to true to keep the
// top bits that would otherwise be shifted out
void bitvector_shl_to(u_int32_t *dest, u_int32_t *b, size_t n, u_int32_t s,
bool_t scrap)
{
u_int32_t i, j, sc=0;
if (n == 0) return;
if (s == 0) {
memcpy(dest, b, n*4);
return;
}
j = (s>>5);
if (j) {
n -= j;
memset(dest, 0, j*4);
s &= 31;
dest = &dest[j];
}
for(i=0; i < n; i++) {
dest[i] = (b[i]<<s) | sc;
sc = b[i]>>(32-s);
}
if (scrap)
dest[i] = sc;
}
adding => form of cond clauses adding path.exists? R6RS psyntax simple example now works
2009-08-13 23:17:21 -04:00
// set nbits to c, starting at given bit offset
// assumes offs < 32
void bitvector_fill(u_int32_t *b, u_int32_t offs, u_int32_t c, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t mask;
if (nbits == 0) return;
nw = (offs+nbits+31)>>5;
if (nw == 1) {
mask = (lomask(nbits)<<offs);
if (c) b[0]|=mask; else b[0]&=(~mask);
return;
}
mask = lomask(offs);
if (c) b[0]|=(~mask); else b[0]&=mask;
if (c) mask=ONES32; else mask = 0;
for(i=1; i < nw-1; i++)
b[i] = mask;
tail = (offs+nbits)&31;
if (tail==0) {
b[i] = mask;
}
else {
mask = lomask(tail);
if (c) b[i]|=mask; else b[i]&=(~mask);
}
}
support reading hex float literals better text representation of infs and nans removing construction of low-level numeric types directly from strings adding hash function corresponding to equal better way to initialize builtins moving advanced bitvector ops to separate compilation unit rearranging hash table code so it can be specialized for different comparison functions one good way to bloat a piece of software is to add several ASCII pictures of the mona lisa
2008-11-23 02:12:37 -05:00
void bitvector_not(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t mask;
if (nbits == 0) return;
nw = (offs+nbits+31)>>5;
if (nw == 1) {
mask = (lomask(nbits)<<offs);
b[0] ^= mask;
return;
}
mask = ~lomask(offs);
b[0]^=mask;
for(i=1; i < nw-1; i++)
b[i] = ~b[i];
tail = (offs+nbits)&31;
if (tail==0) {
b[i] = ~b[i];
}
else {
mask = lomask(tail);
b[i]^=mask;
}
}
// constant-space bit vector copy in a single pass, with arbitrary
// offsets and lengths. to get this right, there are 16 cases to handle!
#define BITVECTOR_COPY_OP(name, OP) \
void bitvector_##name(u_int32_t *dest, u_int32_t doffs, \
u_int32_t *src, u_int32_t soffs, u_int32_t nbits) \
{ \
index_t i; \
u_int32_t s, nw, tail, snw; \
u_int32_t mask, scrap; \
\
if (nbits == 0) return; \
nw = (doffs+nbits+31)>>5; \
\
if (soffs == doffs) { \
if (nw == 1) { \
mask = (lomask(nbits)<<doffs); \
dest[0] = (dest[0] & ~mask) | (OP(src[0]) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = (dest[0] & ~mask) | (OP(src[0]) & mask); \
for(i=1; i < nw-1; i++) \
dest[i] = OP(src[i]); \
tail = (doffs+nbits)&31; \
if (tail==0) { dest[i]=src[i]; } else { \
mask = lomask(tail); \
dest[i] = (dest[i] & ~mask) | (OP(src[i]) & mask); } \
return; \
} \
snw = (soffs+nbits+31)>>5; \
if (soffs < doffs) { \
s = doffs-soffs; \
if (nw == 1) { \
mask = (lomask(nbits)<<doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0])<<s) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0])<<s) & mask); \
scrap = OP(src[0])>>(32-s); \
for(i=1; i < snw-1; i++) { \
dest[i] = (OP(src[i])<<s) | scrap; \
scrap = OP(src[i])>>(32-s); \
} \
tail = (doffs+nbits)&31; \
if (tail==0) { mask=ONES32; } else { mask = lomask(tail); } \
if (snw == nw) { \
dest[i] = (dest[i] & ~mask) | (((OP(src[i])<<s)|scrap) & mask); \
} \
else /* snw < nw */ { \
if (snw == 1) { \
dest[i] = (dest[i] & ~mask) | \
(((OP(src[i])<<s) | scrap) & mask); \
} \
else { \
dest[i] = (OP(src[i])<<s) | scrap; \
scrap = OP(src[i])>>(32-s); \
i++; \
dest[i] = (dest[i] & ~mask) | (scrap & mask); \
} \
} \
} \
else { \
s = soffs-doffs; \
if (snw == 1) { \
mask = (lomask(nbits)<<doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0])>>s) & mask); \
return; \
} \
if (nw == 1) { \
mask = (lomask(nbits)<<doffs); \
dest[0] = (dest[0] & ~mask) | \
(((OP(src[0])>>s)|(OP(src[1])<<(32-s))) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = (dest[0] & ~mask) | \
(((OP(src[0])>>s)|(OP(src[1])<<(32-s))) & mask); \
for(i=1; i < nw-1; i++) { \
dest[i] = (OP(src[i])>>s) | (OP(src[i+1])<<(32-s)); \
} \
tail = (doffs+nbits)&31; \
if (tail==0) { mask=ONES32; } else { mask = lomask(tail); } \
if (snw == nw) { \
dest[i] = (dest[i] & ~mask) | ((OP(src[i])>>s) & mask); \
} \
else /* snw > nw */ { \
dest[i] = (dest[i] & ~mask) | \
(((OP(src[i])>>s)|(OP(src[i+1])<<(32-s))) & mask); \
} \
} \
}
#define BV_COPY(a) (a)
#define BV_NOT(a) (~(a))
BITVECTOR_COPY_OP(copy, BV_COPY)
BITVECTOR_COPY_OP(not_to, BV_NOT)
// right-shift the bits in one logical "row" of a long 2d bit vector
/*
void bitvector_shr_row(u_int32_t *b, u_int32_t offs, size_t nbits, u_int32_t s)
{
}
*/
// copy from source to dest while reversing bit-order
// assumes dest offset == 0
// assumes source and dest don't overlap
// assumes offset < 32
void bitvector_reverse_to(u_int32_t *dest, u_int32_t *src, u_int32_t soffs,
u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
if (nbits == 0) return;
nw = (soffs+nbits+31)>>5;
// first, reverse the words while reversing bit order within each word
for(i=0; i < nw/2; i++) {
dest[i] = bitreverse(src[nw-i-1]);
dest[nw-i-1] = bitreverse(src[i]);
}
if (nw&0x1)
dest[i] = bitreverse(src[i]);
tail = (soffs+nbits)&31;
if (tail)
bitvector_shr(dest, nw, 32-tail);
}
void bitvector_reverse(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t *temp;
if (nbits == 0) return;
nw = (offs+nbits+31)>>5;
temp = (nw > MALLOC_CUTOFF) ? malloc(nw*4) : alloca(nw*4);
for(i=0; i < nw/2; i++) {
temp[i] = bitreverse(b[nw-i-1]);
temp[nw-i-1] = bitreverse(b[i]);
}
if (nw&0x1)
temp[i] = bitreverse(b[i]);
tail = (offs+nbits)&31;
bitvector_copy(b, offs, temp, (32-tail)&31, nbits);
if (nw > MALLOC_CUTOFF) free(temp);
}
u_int64_t bitvector_count(u_int32_t *b, u_int32_t offs, u_int64_t nbits)
{
size_t i, nw;
u_int32_t ntail;
u_int64_t ans;
if (nbits == 0) return 0;
nw = ((u_int64_t)offs+nbits+31)>>5;
if (nw == 1) {
return count_bits(b[0] & (lomask(nbits)<<offs));
}
ans = count_bits(b[0]>>offs); // first end cap
for(i=1; i < nw-1; i++) {
/* popcnt can be computed branch-free, so these special cases
probably don't help much */
/*
v = b[i];
if (v == 0)
continue;
if (v == ONES32)
ans += 32;
else
*/
ans += count_bits(b[i]);
}
ntail = (offs+(u_int32_t)nbits)&31;
ans += count_bits(b[i]&(ntail>0?lomask(ntail):ONES32)); // last end cap
return ans;
}
u_int32_t bitvector_any0(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t mask;
if (nbits == 0) return 0;
nw = (offs+nbits+31)>>5;
if (nw == 1) {
mask = (lomask(nbits)<<offs);
if ((b[0] & mask) != mask) return 1;
return 0;
}
mask = ~lomask(offs);
if ((b[0] & mask) != mask) return 1;
for(i=1; i < nw-1; i++) {
if (b[i] != ONES32) return 1;
}
tail = (offs+nbits)&31;
if (tail==0) {
if (b[i] != ONES32) return 1;
}
else {
mask = lomask(tail);
if ((b[i] & mask) != mask) return 1;
}
return 0;
}
u_int32_t bitvector_any1(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t mask;
if (nbits == 0) return 0;
nw = (offs+nbits+31)>>5;
if (nw == 1) {
mask = (lomask(nbits)<<offs);
if ((b[0] & mask) != 0) return 1;
return 0;
}
mask = ~lomask(offs);
if ((b[0] & mask) != 0) return 1;
for(i=1; i < nw-1; i++) {
if (b[i] != 0) return 1;
}
tail = (offs+nbits)&31;
if (tail==0) {
if (b[i] != 0) return 1;
}
else {
mask = lomask(tail);
if ((b[i] & mask) != 0) return 1;
}
return 0;
}
static void adjust_offset_to(u_int32_t *dest, u_int32_t *src, u_int32_t nw,
u_int32_t soffs, u_int32_t newoffs)
{
if (newoffs > soffs)
clarifying which values are unspecified, and making the unspecified value true, since only #f should be false. removing not-really-used definitions of true and false, which just seem to be asking for conflicts
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bitvector_shl_to(dest, src, nw, newoffs-soffs, 1);
support reading hex float literals better text representation of infs and nans removing construction of low-level numeric types directly from strings adding hash function corresponding to equal better way to initialize builtins moving advanced bitvector ops to separate compilation unit rearranging hash table code so it can be specialized for different comparison functions one good way to bloat a piece of software is to add several ASCII pictures of the mona lisa
2008-11-23 02:12:37 -05:00
else
bitvector_shr_to(dest, src, nw, soffs-newoffs);
}
#define BITVECTOR_BINARY_OP_TO(opname, OP) \
void bitvector_##opname##_to(u_int32_t *dest, u_int32_t doffs, \
u_int32_t *a, u_int32_t aoffs, \
u_int32_t *b, u_int32_t boffs, u_int32_t nbits) \
{ \
u_int32_t nw = (doffs+nbits+31)>>5; \
u_int32_t *temp = nw>MALLOC_CUTOFF ? malloc((nw+1)*4) : alloca((nw+1)*4);\
u_int32_t i, anw, bnw; \
if (aoffs == boffs) { \
anw = (aoffs+nbits+31)>>5; \
} \
else if (aoffs == doffs) { \
bnw = (boffs+nbits+31)>>5; \
adjust_offset_to(temp, b, bnw, boffs, aoffs); \
b = temp; anw = nw; \
} \
else { \
anw = (aoffs+nbits+31)>>5; \
bnw = (boffs+nbits+31)>>5; \
adjust_offset_to(temp, a, anw, aoffs, boffs); \
a = temp; aoffs = boffs; anw = bnw; \
} \
for(i=0; i < anw; i++) temp[i] = OP(a[i], b[i]); \
bitvector_copy(dest, doffs, temp, aoffs, nbits); \
if (nw>MALLOC_CUTOFF) free(temp); \
}
#define BV_AND(a,b) ((a)&(b))
#define BV_OR(a,b) ((a)|(b))
#define BV_XOR(a,b) ((a)^(b))
BITVECTOR_BINARY_OP_TO(and, BV_AND)
BITVECTOR_BINARY_OP_TO(or, BV_OR)
BITVECTOR_BINARY_OP_TO(xor, BV_XOR)