Begun work on bignums; changed integer size to 64 bits

I'm fairly sure the size of a long int on my machines is 64 bit anyway, but for portability it needs to be explicit.
This commit is contained in:
Simon Brooke 2018-12-25 13:18:37 +00:00
parent ad9b1cd7f8
commit 6ee9f9b59a
13 changed files with 109 additions and 25 deletions

14
src/arith/bignum.c Normal file
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@ -0,0 +1,14 @@
/*
* bignum.c
*
* Allocation of and operations on arbitrary precision integers.
*
* (c) 2018 Simon Brooke <simon@journeyman.cc>
* Licensed under GPL version 2.0, or, at your option, any later version.
*/
/*
* Bignums generally follow Knuth, vol 2, 4.3. The word size is 64 bits,
* and words are stored in individual cons-space objects, comprising the
* word itself and a pointer to the next word in the number.
*/

16
src/arith/bignum.h Normal file
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@ -0,0 +1,16 @@
/**
* bignum.h
*
* functions for bignum cells.
*
*
* (c) 2017 Simon Brooke <simon@journeyman.cc>
* Licensed under GPL version 2.0, or, at your option, any later version.
*/
#ifndef __bignum_h
#define __bignum_h
#endif

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@ -35,7 +35,7 @@ long double numeric_value( struct cons_pointer pointer ) {
/**
* Allocate an integer cell representing this value and return a cons pointer to it.
*/
struct cons_pointer make_integer( long int value ) {
struct cons_pointer make_integer( int64_t value ) {
struct cons_pointer result = allocate_cell( INTEGERTAG );
struct cons_space_object *cell = &pointer2cell( result );
cell->payload.integer.value = value;

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@ -16,6 +16,6 @@ long double numeric_value( struct cons_pointer pointer );
/**
* Allocate an integer cell representing this value and return a cons pointer to it.
*/
struct cons_pointer make_integer( long int value );
struct cons_pointer make_integer( int64_t value );
#endif

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@ -27,7 +27,7 @@
#include "stack.h"
long double to_long_double( struct cons_pointer arg );
long int to_long_int( struct cons_pointer arg );
int64_t to_long_int( struct cons_pointer arg );
struct cons_pointer add_2( struct stack_frame *frame, struct cons_pointer arg1,
struct cons_pointer arg2 );
@ -97,8 +97,8 @@ long double to_long_double( struct cons_pointer arg ) {
* if a ratio may legally have zero as a divisor, or something which is
* not a number (or is a big number) is passed in.
*/
long int to_long_int( struct cons_pointer arg ) {
long int result = 0;
int64_t to_long_int( struct cons_pointer arg ) {
int64_t result = 0;
struct cons_space_object cell = pointer2cell( arg );
switch ( cell.tag.value ) {
case INTEGERTV:
@ -125,10 +125,13 @@ struct cons_pointer add_2( struct stack_frame *frame, struct cons_pointer arg1,
struct cons_space_object cell1 = pointer2cell( arg1 );
struct cons_space_object cell2 = pointer2cell( arg2 );
#ifdef DEBUG
fputws( L"add_2( arg1 = ", stderr );
print( stderr, arg1 );
fputws( L"; arg2 = ", stderr );
print( stderr, arg2 );
fputws( L")\n", stderr);
#endif
if ( zerop( arg1 ) ) {
result = arg2;
@ -199,9 +202,11 @@ struct cons_pointer add_2( struct stack_frame *frame, struct cons_pointer arg1,
}
}
#ifdef DEBUG
fputws( L"}; => ", stderr );
print( stderr, arg2 );
fputws( L"\n", stderr );
#endif
return result;
}
@ -254,17 +259,19 @@ struct cons_pointer multiply_2( struct stack_frame *frame,
struct cons_space_object cell1 = pointer2cell( arg1 );
struct cons_space_object cell2 = pointer2cell( arg2 );
#ifdef DEBUG
fputws( L"multiply_2( arg1 = ", stderr );
print( stderr, arg1 );
fputws( L"; arg2 = ", stderr );
print( stderr, arg2 );
fputws( L")\n", stderr);
#endif
if ( zerop( arg1 ) ) {
result = arg2;
} else if ( zerop( arg2 ) ) {
result = arg1;
} else {
switch ( cell1.tag.value ) {
case EXCEPTIONTV:
result = arg1;
@ -328,9 +335,11 @@ struct cons_pointer multiply_2( struct stack_frame *frame,
}
}
fputws( L"}; => ", stderr );
#ifdef DEBUG
fputws( L" => ", stderr );
print( stderr, arg2 );
fputws( L"\n", stderr );
#endif
return result;
}

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@ -28,9 +28,9 @@ struct cons_pointer inverse( struct stack_frame *frame,
struct cons_pointer arg );
/**
* return, as a long int, the greatest common divisor of `m` and `n`,
* return, as a int64_t, the greatest common divisor of `m` and `n`,
*/
long int greatest_common_divisor( long int m, long int n ) {
int64_t greatest_common_divisor( int64_t m, int64_t n ) {
int o;
while ( m ) {
o = m;
@ -42,9 +42,9 @@ long int greatest_common_divisor( long int m, long int n ) {
}
/**
* return, as a long int, the least common multiple of `m` and `n`,
* return, as a int64_t, the least common multiple of `m` and `n`,
*/
long int least_common_multiple( long int m, long int n ) {
int64_t least_common_multiple( int64_t m, int64_t n ) {
return m / greatest_common_divisor( m, n ) * n;
}
@ -59,7 +59,7 @@ struct cons_pointer simplify_ratio( struct stack_frame *frame,
struct cons_pointer result = arg;
if (ratiop(arg)) {
long int ddrv =
int64_t ddrv =
pointer2cell( pointer2cell( arg ).payload.ratio.dividend ).
payload.integer.value, drrv =
pointer2cell( pointer2cell( arg ).payload.ratio.divisor ).
@ -106,7 +106,7 @@ struct cons_pointer add_ratio_ratio( struct stack_frame *frame,
if ( ratiop(arg1) && ratiop(arg2)) {
struct cons_space_object cell1 = pointer2cell( arg1 );
struct cons_space_object cell2 = pointer2cell( arg2 );
long int dd1v =
int64_t dd1v =
pointer2cell( cell1.payload.ratio.dividend ).payload.integer.value,
dd2v =
pointer2cell( cell2.payload.ratio.dividend ).payload.integer.value,
@ -231,7 +231,7 @@ struct cons_pointer multiply_ratio_ratio( struct
if ( ratiop(arg1) && ratiop(arg2)) {
struct cons_space_object cell1 = pointer2cell( arg1 );
struct cons_space_object cell2 = pointer2cell( arg2 );
long int dd1v =
int64_t dd1v =
pointer2cell( cell1.payload.ratio.dividend ).payload.integer.value,
dd2v =
pointer2cell( cell2.payload.ratio.dividend ).payload.integer.value,

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@ -127,8 +127,10 @@ void dump_pages( FILE * output ) {
void free_cell( struct cons_pointer pointer ) {
struct cons_space_object *cell = &pointer2cell( pointer );
#ifdef DEBUG
fwprintf( stderr, L"Freeing cell " );
dump_object( stderr, pointer );
#endif
switch ( cell->tag.value ) {
/* for all the types of cons-space object which point to other
@ -173,7 +175,7 @@ void free_cell( struct cons_pointer pointer ) {
if ( !check_tag( pointer, FREETAG ) ) {
if ( cell->count == 0 ) {
strncpy( &cell->tag.bytes[0], FREETAG, 4 );
strncpy( &cell->tag.bytes[0], FREETAG, TAGLENGTH );
cell->payload.free.car = NIL;
cell->payload.free.cdr = freelist;
freelist = pointer;
@ -209,7 +211,7 @@ struct cons_pointer allocate_cell( char *tag ) {
if ( strncmp( &cell->tag.bytes[0], FREETAG, TAGLENGTH ) == 0 ) {
freelist = cell->payload.free.cdr;
strncpy( &cell->tag.bytes[0], tag, 4 );
strncpy( &cell->tag.bytes[0], tag, TAGLENGTH );
cell->count = 0;
cell->payload.cons.car = NIL;

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@ -28,6 +28,13 @@
/**
* tag values, all of which must be 4 bytes. Must not collide with vector space tag values
*/
/**
* A word within a bignum - arbitrary precision integer.
*/
#define BIGNUMTAG "BIGN"
#define BIGNUMTV 1313294658
/**
* An ordinary cons cell: 1397641027
*/
@ -38,7 +45,6 @@
* An exception.
*/
#define EXCEPTIONTAG "EXEP"
/* TODO: this is wrong */
#define EXCEPTIONTV 1346721861
/**
@ -162,6 +168,11 @@
*/
#define nilp(conspoint) (check_tag(conspoint,NILTAG))
/**
* true if conspointer points to a cons cell, else false
*/
#define bignump(conspoint) (check_tag(conspoint,BIGNUMTAG))
/**
* true if conspointer points to a cons cell, else false
*/
@ -221,7 +232,7 @@
* true if conspointer points to some sort of a number cell,
* else false
*/
#define numberp(conspoint) (check_tag(conspoint,INTEGERTAG)||check_tag(conspoint,RATIOTAG)||heck_tag(conspoint,REALTAG))
#define numberp(conspoint) (check_tag(conspoint,INTEGERTAG)||check_tag(conspoint,RATIOTAG)||check_tag(conspoint,REALTAG)||check_tag(conspoint,BIGNUMTAG))
/**
* true if thr conspointer points to a vector pointer.
@ -274,6 +285,16 @@ struct stack_frame {
struct cons_pointer function; /* the function to be called */
};
/**
* payload of a bignum cell. Intentionally similar to an integer payload, but
* with a next pointer.
*/
struct bignum_payload {
int64_t value;
struct cons_pointer next;
};
/**
* payload of a cons cell.
*/
@ -321,7 +342,7 @@ struct free_payload {
* optional bignum object.
*/
struct integer_payload {
long int value;
int64_t value;
};
/**

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@ -45,9 +45,9 @@ struct cons_pointer make_vec_pointer( char *tag, uint64_t address ) {
* NOTE that `tag` should be the vector-space tag of the particular type of
* vector-space object, NOT `VECTORPOINTTAG`.
*/
struct cons_pointer make_vso( char *tag, long int payload_size ) {
struct cons_pointer make_vso( char *tag, int64_t payload_size ) {
struct cons_pointer result = NIL;
long int total_size = sizeof( struct vector_space_header ) + payload_size;
int64_t total_size = sizeof( struct vector_space_header ) + payload_size;
struct vector_space_header *vso = malloc( total_size );

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@ -34,6 +34,11 @@
#define NAMESPACETAG "NMSP"
#define NAMESPACETV 0
/*
* a stack frame.
*/
#define STACKFRAMETAG "STAK"
#define STACKFRAMETV
/*
* a vector of cons pointers.
*/
@ -42,7 +47,7 @@
#define pointer_to_vso(pointer)(vectorpointp(pointer)? pointer2cell(pointer).payload.vectorp.address : 0)
struct cons_pointer make_vso( char *tag, long int payload_size );
struct cons_pointer make_vso( char *tag, int64_t payload_size );
struct vector_space_header {
union {

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@ -125,8 +125,8 @@ struct cons_pointer read_continuation( struct stack_frame *frame, FILE * input,
struct cons_pointer read_number( struct stack_frame *frame, FILE * input,
wint_t initial, bool seen_period ) {
struct cons_pointer result = NIL;
long int accumulator = 0;
long int dividend = 0;
int64_t accumulator = 0;
int64_t dividend = 0;
int places_of_decimals = 0;
wint_t c;
fwprintf( stderr, L"read_number starting '%c' (%d)\n", initial, initial );

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@ -1,9 +1,26 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define TAGLENGTH 4
struct dummy {
union {
char bytes[TAGLENGTH]; /* the tag (type) of this cell,
* considered as bytes */
uint32_t value; /* the tag considered as a number */
} tag;
};
int main( int argc, char *argv[] ) {
struct dummy *b = malloc( sizeof( struct dummy));
struct dummy buffer = *b;
for (int i = 1; i < argc; i++) {
printf( "%4.4s:\t%u\n", argv[i], (uint32_t)*argv[i]);
strncpy( &buffer.tag.bytes[0], argv[i], TAGLENGTH );
printf( "%4.4s:\t%d\n", argv[i], buffer.tag.value);
}
}

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