/**
         
 * 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.
         
 */
         

         
import {check_integer, is_bigint, exec_eval, deref, exec_build,
         
    widen_bigint, norm_bigint, make_error, Compound,
         
    add, make_check, norm_float, exec_unify, make_arithmetic
         
} from "../../dogelog.mjs";
         

         

         
function test_random(args) {
         
    let alpha = norm_float(Math.random());
         
    return exec_unify(args[0], alpha);
         
}
         

         

         
function arit_msb(args) {
         
    let alpha = exec_eval(args[0]);
         
    check_integer(alpha);
         
    if (!is_bigint(alpha)) {
         
        return 31 - Math.clz32((alpha < 0 ? ~alpha : alpha));
         
    } else {
         
        return bigint_msb(alpha < 0 ? ~alpha : alpha);
         
    }
         
}
         

         
function arit_lsb(args) {
         
    let alpha = exec_eval(args[0]);
         
    check_integer(alpha);
         
    if (!is_bigint(alpha)) {
         
        return 31 - Math.clz32(alpha & -alpha);
         
    } else {
         
        return bigint_msb(alpha & -alpha);
         
    }
         
}
         

         
function bigint_msb(alpha) {
         
    alpha = alpha.toString(16);
         
    return 31 - Math.clz32(hexvalue(alpha.codePointAt(0))) + (alpha.length - 1)*4;
         
}
         

         
function hexvalue(ch) {
         
    if (48 <= ch && ch <= 57) {
         
        return ch - 48;
         
    } else if (65 <= ch && ch <= 70) {
         
        return ch - 65 + 10;
         
    } else if (97 <= ch && ch <= 102) {
         
        return ch - 97 + 10;
         
    } else {
         
        return -1;
         
    }
         
}
         

         
function test_testbit(args) {
         
    let alpha = deref(exec_build(args[0]));
         
    check_integer(alpha);
         
    let beta = deref(exec_build(args[1]));
         
    check_integer(beta);
         
    if (beta < 0)
         
        throw make_error(new Compound("domain_error",
         
            ["not_less_than_zero", beta]));
         
    return number_testbit(alpha, beta);
         
}
         

         
function number_testbit(alpha, beta) {
         
    if (!is_bigint(alpha) && !is_bigint(beta)) {
         
        if (beta < 31) {
         
            return (alpha & (1 << beta)) !== 0;
         
        } else {
         
            return alpha < 0;
         
        }
         
    } else {
         
        return (widen_bigint(alpha) & (1n << widen_bigint(beta))) !== 0n;
         
    }
         
}
         

         

         
function test_divmod(args) {
         
    let alpha = deref(exec_build(args[0]));
         
    check_integer(alpha);
         
    let beta = deref(exec_build(args[1]));
         
    check_integer(beta);
         
    let divres;
         
    let modres;
         
    if (!is_bigint(alpha) && !is_bigint(beta)) {
         
        divres = Math.floor(alpha / beta);
         
        modres = alpha - divres*beta;
         
    } else {
         
        alpha = widen_bigint(alpha);
         
        beta = widen_bigint(beta);
         
        divres = bigint_div(alpha, beta);
         
        modres = alpha - divres*beta;
         
        divres = norm_bigint(divres);
         
        modres = norm_bigint(modres);
         
    }
         
    if (!exec_unify(args[2], divres))
         
        return false;
         
    return exec_unify(args[3], modres);
         
}
         

         
function bigint_div(alpha, beta) {
         
    let temp = alpha / beta;
         
    if ((alpha < 0) !== (beta < 0)) {
         
        let res = alpha % beta;
         
        if (res !== 0)
         
            temp--;
         
    }
         
    return temp;
         
}
         

         

         
export function main() {
         
    add("random", 1, make_check(test_random));
         
    add("msb", 2, make_arithmetic(arit_msb));
         
    add("lsb", 2, make_arithmetic(arit_lsb));
         
    add("testbit", 2, make_check(test_testbit));
         
    add("divmod", 4, make_check(test_divmod));
         
}