factor/vm/math.c

#include "master.h"

/* Fixnums */
F_FIXNUM to_fixnum(CELL tagged)
{
	switch(TAG(tagged))
	{
	case FIXNUM_TYPE:
		return untag_fixnum_fast(tagged);
	case BIGNUM_TYPE:
		return bignum_to_fixnum(untag_object(tagged));
	default:
		type_error(FIXNUM_TYPE,tagged);
		return -1; /* can't happen */
	}
}

CELL to_cell(CELL tagged)
{
	return (CELL)to_fixnum(tagged);
}

void primitive_bignum_to_fixnum(void)
{
	drepl(tag_fixnum(bignum_to_fixnum(untag_object(dpeek()))));
}

void primitive_float_to_fixnum(void)
{
	drepl(tag_fixnum(float_to_fixnum(dpeek())));
}

/* The fixnum+, fixnum- and fixnum* primitives are defined in cpu_*.S. On
overflow, they call these functions. */
F_FASTCALL void overflow_fixnum_add(F_FIXNUM x, F_FIXNUM y)
{
	drepl(tag_bignum(fixnum_to_bignum(
		untag_fixnum_fast(x) + untag_fixnum_fast(y))));
}

F_FASTCALL void overflow_fixnum_subtract(F_FIXNUM x, F_FIXNUM y)
{
	drepl(tag_bignum(fixnum_to_bignum(
		untag_fixnum_fast(x) - untag_fixnum_fast(y))));
}

F_FASTCALL void overflow_fixnum_multiply(F_FIXNUM x, F_FIXNUM y)
{
	F_ARRAY *bx = fixnum_to_bignum(x);
	REGISTER_BIGNUM(bx);
	F_ARRAY *by = fixnum_to_bignum(y);
	UNREGISTER_BIGNUM(bx);
	drepl(tag_bignum(bignum_multiply(bx,by)));
}

/* Division can only overflow when we are dividing the most negative fixnum
by -1. */
void primitive_fixnum_divint(void)
{
	F_FIXNUM y = untag_fixnum_fast(dpop()); \
	F_FIXNUM x = untag_fixnum_fast(dpeek());
	F_FIXNUM result = x / y;
	if(result == -FIXNUM_MIN)
		drepl(allot_integer(-FIXNUM_MIN));
	else
		drepl(tag_fixnum(result));
}

void primitive_fixnum_divmod(void)
{
	F_FIXNUM y = get(ds);
	F_FIXNUM x = get(ds - CELLS);
	if(y == tag_fixnum(-1) && x == tag_fixnum(FIXNUM_MIN))
	{
		put(ds - CELLS,allot_integer(-FIXNUM_MIN));
		put(ds,tag_fixnum(0));
	}
	else
	{
		put(ds - CELLS,tag_fixnum(x / y));
		put(ds,x % y);
	}
}

/*
 * If we're shifting right by n bits, we won't overflow as long as none of the
 * high WORD_SIZE-TAG_BITS-n bits are set.
 */
#define SIGN_MASK(x) ((x) >> (WORD_SIZE - 1))
#define BRANCHLESS_MAX(x,y) ((x) - (((x) - (y)) & SIGN_MASK((x) - (y))))
#define BRANCHLESS_ABS(x) ((x ^ SIGN_MASK(x)) - SIGN_MASK(x))

void primitive_fixnum_shift(void)
{
	F_FIXNUM y = untag_fixnum_fast(dpop()); \
	F_FIXNUM x = untag_fixnum_fast(dpeek());

	if(x == 0)
		return;
	else if(y < 0)
	{
		y = BRANCHLESS_MAX(y,-WORD_SIZE + 1);
		drepl(tag_fixnum(x >> -y));
		return;
	}
	else if(y < WORD_SIZE - TAG_BITS)
	{
		F_FIXNUM mask = -((F_FIXNUM)1 << (WORD_SIZE - 1 - TAG_BITS - y));
		if(!(BRANCHLESS_ABS(x) & mask))
		{
			drepl(tag_fixnum(x << y));
			return;
		}
	}

	drepl(tag_bignum(bignum_arithmetic_shift(
		fixnum_to_bignum(x),y)));
}

/* Bignums */
void primitive_fixnum_to_bignum(void)
{
	drepl(tag_bignum(fixnum_to_bignum(untag_fixnum_fast(dpeek()))));
}

void primitive_float_to_bignum(void)
{
	drepl(tag_bignum(float_to_bignum(dpeek())));
}

#define POP_BIGNUMS(x,y) \
	F_ARRAY *y = untag_object(dpop()); \
	F_ARRAY *x = untag_object(dpop());

void primitive_bignum_eq(void)
{
	POP_BIGNUMS(x,y);
	box_boolean(bignum_equal_p(x,y));
}

void primitive_bignum_add(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_add(x,y)));
}

void primitive_bignum_subtract(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_subtract(x,y)));
}

void primitive_bignum_multiply(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_multiply(x,y)));
}

void primitive_bignum_divint(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_quotient(x,y)));
}

void primitive_bignum_divmod(void)
{
	F_ARRAY *q, *r;
	POP_BIGNUMS(x,y);
	bignum_divide(x,y,&q,&r);
	dpush(tag_bignum(q));
	dpush(tag_bignum(r));
}

void primitive_bignum_mod(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_remainder(x,y)));
}

void primitive_bignum_and(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_bitwise_and(x,y)));
}

void primitive_bignum_or(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_bitwise_ior(x,y)));
}

void primitive_bignum_xor(void)
{
	POP_BIGNUMS(x,y);
	dpush(tag_bignum(bignum_bitwise_xor(x,y)));
}

void primitive_bignum_shift(void)
{
	F_FIXNUM y = untag_fixnum_fast(dpop());
        F_ARRAY* x = untag_object(dpop());
	dpush(tag_bignum(bignum_arithmetic_shift(x,y)));
}

void primitive_bignum_less(void)
{
	POP_BIGNUMS(x,y);
	box_boolean(bignum_compare(x,y) == bignum_comparison_less);
}

void primitive_bignum_lesseq(void)
{
	POP_BIGNUMS(x,y);
	box_boolean(bignum_compare(x,y) != bignum_comparison_greater);
}

void primitive_bignum_greater(void)
{
	POP_BIGNUMS(x,y);
	box_boolean(bignum_compare(x,y) == bignum_comparison_greater);
}

void primitive_bignum_greatereq(void)
{
	POP_BIGNUMS(x,y);
	box_boolean(bignum_compare(x,y) != bignum_comparison_less);
}

void primitive_bignum_not(void)
{
	drepl(tag_bignum(bignum_bitwise_not(untag_object(dpeek()))));
}

void primitive_bignum_bitp(void)
{
	F_FIXNUM bit = to_fixnum(dpop());
	F_ARRAY *x = untag_object(dpop());
	box_boolean(bignum_logbitp(bit,x));
}

void primitive_bignum_log2(void)
{
	drepl(tag_bignum(bignum_integer_length(untag_object(dpeek()))));
}

unsigned int bignum_producer(unsigned int digit)
{
	unsigned char *ptr = alien_offset(dpeek());
	return *(ptr + digit);
}

void primitive_byte_array_to_bignum(void)
{
	type_check(BYTE_ARRAY_TYPE,dpeek());
	CELL n_digits = array_capacity(untag_object(dpeek()));
	bignum_type bignum = digit_stream_to_bignum(
		n_digits,bignum_producer,0x100,0);
	drepl(tag_bignum(bignum));
}

void box_signed_1(s8 n)
{
	dpush(tag_fixnum(n));
}

void box_unsigned_1(u8 n)
{
	dpush(tag_fixnum(n));
}

void box_signed_2(s16 n)
{
	dpush(tag_fixnum(n));
}

void box_unsigned_2(u16 n)
{
	dpush(tag_fixnum(n));
}

void box_signed_4(s32 n)
{
	dpush(allot_integer(n));
}

void box_unsigned_4(u32 n)
{
	dpush(allot_cell(n));
}

void box_signed_cell(F_FIXNUM integer)
{
	dpush(allot_integer(integer));
}

void box_unsigned_cell(CELL cell)
{
	dpush(allot_cell(cell));
}

void box_signed_8(s64 n)
{
	if(n < FIXNUM_MIN || n > FIXNUM_MAX)
		dpush(tag_bignum(long_long_to_bignum(n)));
	else
		dpush(tag_fixnum(n));
}

s64 to_signed_8(CELL obj)
{
	switch(type_of(obj))
	{
	case FIXNUM_TYPE:
		return untag_fixnum_fast(obj);
	case BIGNUM_TYPE:
		return bignum_to_long_long(untag_object(obj));
	default:
		type_error(BIGNUM_TYPE,obj);
		return -1;
	}
}

void box_unsigned_8(u64 n)
{
	if(n > FIXNUM_MAX)
		dpush(tag_bignum(ulong_long_to_bignum(n)));
	else
		dpush(tag_fixnum(n));
}

u64 to_unsigned_8(CELL obj)
{
	switch(type_of(obj))
	{
	case FIXNUM_TYPE:
		return untag_fixnum_fast(obj);
	case BIGNUM_TYPE:
		return bignum_to_ulong_long(untag_object(obj));
	default:
		type_error(BIGNUM_TYPE,obj);
		return -1;
	}
}

CELL unbox_array_size(void)
{
	switch(type_of(dpeek()))
	{
	case FIXNUM_TYPE:
		{
			F_FIXNUM n = untag_fixnum_fast(dpeek());
			if(n >= 0 && n < ARRAY_SIZE_MAX)
			{
				dpop();
				return n;
			}
			break;
		}
	case BIGNUM_TYPE:
		{
			bignum_type zero = untag_object(bignum_zero);
			bignum_type max = cell_to_bignum(ARRAY_SIZE_MAX);
			bignum_type n = untag_object(dpeek());
			if(bignum_compare(n,zero) != bignum_comparison_less
				&& bignum_compare(n,max) == bignum_comparison_less)
			{
				dpop();
				return bignum_to_cell(n);
			}
			break;
		}
	}

	general_error(ERROR_ARRAY_SIZE,dpop(),tag_fixnum(ARRAY_SIZE_MAX),NULL);
	return 0; /* can't happen */
}

/* Ratios */

/* Does not reduce to lowest terms, so should only be used by math
library implementation, to avoid breaking invariants. */
void primitive_from_fraction(void)
{
	F_RATIO* ratio = allot_object(RATIO_TYPE,sizeof(F_RATIO));
	ratio->denominator = dpop();
	ratio->numerator = dpop();
	dpush(RETAG(ratio,RATIO_TYPE));
}

/* Floats */
void primitive_fixnum_to_float(void)
{
	drepl(allot_float(fixnum_to_float(dpeek())));
}

void primitive_bignum_to_float(void)
{
	drepl(allot_float(bignum_to_float(dpeek())));
}

void primitive_str_to_float(void)
{
	char *c_str, *end;
	double f;
	F_STRING *str = untag_string(dpeek());
	CELL capacity = string_capacity(str);

	c_str = to_char_string(str,false);
	end = c_str;
	f = strtod(c_str,&end);
	if(end != c_str + capacity)
		drepl(F);
	else
		drepl(allot_float(f));
}

void primitive_float_to_str(void)
{
	char tmp[33];
	snprintf(tmp,32,"%.16g",untag_float(dpop()));
	tmp[32] = '\0';
	box_char_string(tmp);
}

#define POP_FLOATS(x,y) \
	double y = untag_float_fast(dpop()); \
	double x = untag_float_fast(dpop());

void primitive_float_eq(void)
{
	POP_FLOATS(x,y);
	box_boolean(x == y);
}

void primitive_float_add(void)
{
	POP_FLOATS(x,y);
	box_double(x + y);
}

void primitive_float_subtract(void)
{
	POP_FLOATS(x,y);
	box_double(x - y);
}

void primitive_float_multiply(void)
{
	POP_FLOATS(x,y);
	box_double(x * y);
}

void primitive_float_divfloat(void)
{
	POP_FLOATS(x,y);
	box_double(x / y);
}

void primitive_float_mod(void)
{
	POP_FLOATS(x,y);
	box_double(fmod(x,y));
}

void primitive_float_less(void)
{
	POP_FLOATS(x,y);
	box_boolean(x < y);
}

void primitive_float_lesseq(void)
{
	POP_FLOATS(x,y);
	box_boolean(x <= y);
}

void primitive_float_greater(void)
{
	POP_FLOATS(x,y);
	box_boolean(x > y);
}

void primitive_float_greatereq(void)
{
	POP_FLOATS(x,y);
	box_boolean(x >= y);
}

void primitive_float_bits(void)
{
	box_unsigned_4(float_bits(untag_float(dpop())));
}

void primitive_bits_float(void)
{
	box_float(bits_float(to_cell(dpop())));
}

void primitive_double_bits(void)
{
	box_unsigned_8(double_bits(untag_float(dpop())));
}

void primitive_bits_double(void)
{
	box_double(bits_double(to_unsigned_8(dpop())));
}

float to_float(CELL value)
{
	return untag_float(value);
}

double to_double(CELL value)
{
	return untag_float(value);
}

void box_float(float flo)
{
        dpush(allot_float(flo));
}

void box_double(double flo)
{
        dpush(allot_float(flo));
}

/* Complex numbers */

void primitive_from_rect(void)
{
	F_COMPLEX* z = allot_object(COMPLEX_TYPE,sizeof(F_COMPLEX));
	z->imaginary = dpop();
	z->real = dpop();
	dpush(RETAG(z,COMPLEX_TYPE));
}