###
# Modern Albufeira Prolog Interpreter
#
# Warranty & Liability
# To the extent permitted by applicable law and unless explicitly
# otherwise agreed upon, XLOG Technologies AG makes no warranties
# regarding the provided information. XLOG Technologies AG assumes
# no liability that any problems might be solved with the information
# provided by XLOG Technologies AG.
#
# Rights & License
# All industrial property rights regarding the information - copyright
# and patent rights in particular - are the sole property of XLOG
# Technologies AG. If the company was not the originator of some
# excerpts, XLOG Technologies AG has at least obtained the right to
# reproduce, change and translate the information.
#
# Reproduction is restricted to the whole unaltered document. Reproduction
# of the information is only allowed for non-commercial uses. Selling,
# giving away or letting of the execution of the library is prohibited.
# The library can be distributed as part of your applications and libraries
# for execution provided this comment remains unchanged.
#
# Restrictions
# Only to be distributed with programs that add significant and primary
# functionality to the library. Not to be distributed with additional
# software intended to replace any components of the library.
#
# Trademarks
# Jekejeke is a registered trademark of XLOG Technologies AG.
##
from nova.core import (set, make_arithmetic, exec_build,
make_check, exec_unify, exec_eval, check_integer,
make_error, Compound)
import random
import math
#####################################################################
# Random Numbers #
#####################################################################
###
# random(F):
# The predicate succeeds in F with a uniform random 64-bit
# floating point value in the interval [0..1).
##
def test_random(args):
alpha = random.random()
return exec_unify(args[0], alpha)
#######################################################################
# msb/2, lsb/2 and popcount/2 #
#######################################################################
###
# msb(X):
# If X is an integer, then the function returns the most significant bit.
##
def arit_msb(args):
alpha = exec_eval(args[0])
check_integer(alpha)
return (~alpha if alpha < 0 else alpha).bit_length() - 1
###
# lsb(X):
# If X is an integer, then the function returns the least significant bit.
##
def arit_lsb(args):
alpha = exec_eval(args[0])
check_integer(alpha)
return (alpha & -alpha).bit_length() - 1
###
# popcount(X):
# If X is an integer, then the function returns the number of ones.
##
def arit_popcount(args):
alpha = exec_eval(args[0])
check_integer(alpha)
if alpha < 0:
alpha = -alpha
return alpha.bit_count() + (alpha & -alpha).bit_length() - 2
else:
return alpha.bit_count()
#######################################################################
# testbit/2, sqrtrem/3 and isqrt/2 #
#######################################################################
###
# testbit(X, Y):
# The predicate succeeds when X /\ (1 << Y) =\= 0.
##
def test_testbit(args):
alpha = exec_build(args[0])
check_integer(alpha)
beta = exec_build(args[1])
check_integer(beta)
if beta < 0:
raise make_error(Compound("domain_error",
["not_less_than_zero", beta]))
return (alpha & (1 << beta)) != 0
###
# sqrtrem(X, Y, Z):
# If X is an integer then the predicate succeeds in Y with the
# integer square root of X, and in Z with the remainder X-Y*Y.
##
def test_sqrtrem(args):
alpha = exec_build(args[0])
check_integer(alpha)
if alpha < 0:
raise make_error(Compound("domain_error",
["not_less_than_zero", alpha]))
ressqrt = math.isqrt(alpha)
resrem = alpha-ressqrt*ressqrt
if not exec_unify(args[1],ressqrt):
return False
return exec_unify(args[2],resrem)
###
# isqrt(X, Y):
# If X is an integer then the predicate succeeds in Y with the
# integer square root of X.
##
def arit_isqrt(args):
alpha = exec_eval(args[0])
check_integer(alpha)
if alpha < 0:
raise make_error(Compound("domain_error",
["not_less_than_zero", alpha]))
return math.isqrt(alpha)
#####################################################################
# Bit Lib Init #
#####################################################################
def main():
set("random", 1, make_check(test_random))
set("msb", 2, make_arithmetic(arit_msb))
set("lsb", 2, make_arithmetic(arit_lsb))
set("popcount", 2, make_arithmetic(arit_popcount))
set("testbit", 2, make_check(test_testbit))
set("sqrtrem", 3, make_check(test_sqrtrem))
set("isqrt", 2, make_arithmetic(arit_isqrt))