comba.py - mozsearch

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#!/usr/bin/python3

import sys

import datetime

# (C) 2011,2014,2015,2016 Jack Lloyd

# Botan is released under the Simplified BSD License (see license.txt)

# Used to generate src/lib/math/mp/mp_comba.cpp

def comba_indexes(N):

    indexes = []

    for i in range(0, 2*N):

        x = []

        for j in range(max(0, i-N+1), min(N, i+1)):

            x += [(j,i-j)]

        indexes += [sorted(x)]

    return indexes

def comba_sqr_indexes(N):

    indexes = []

    for i in range(0, 2*N):

        x = []

        for j in range(max(0, i-N+1), min(N, i+1)):

            if j < i-j:

                x += [(j,i-j)]

            else:

                x += [(i-j,j)]

        indexes += [sorted(x)]

    return indexes

def comba_multiply_code(N):

    indexes = comba_indexes(N)

    w2 = 'w2'

    w1 = 'w1'

    w0 = 'w0'

    for (i,idx) in zip(range(0, len(indexes)), indexes):

        for pair in idx:

            print("   word3_muladd(&%s, &%s, &%s, x[%2d], y[%2d]);" % (w2, w1, w0, pair[0], pair[1]))

        if i < 2*N-2:

            print("   z[%2d] = %s; %s = 0;\n" % (i, w0, w0))

        else:

            print("   z[%2d] = %s;" % (i, w0))

        (w0,w1,w2) = (w1,w2,w0)

        #print("z[%2d] = w0; w0 = w1; w1 = w2; w2 = 0;" % (i))

def comba_square_code(N):

    indexes = comba_sqr_indexes(N)

    w2 = 'w2'

    w1 = 'w1'

    w0 = 'w0'

    for (rnd,idx) in zip(range(0, len(indexes)), indexes):

        for (i,pair) in zip(range(0, len(idx)), idx):

            if pair[0] == pair[1]:

                print("   word3_muladd  (&%s, &%s, &%s, x[%2d], x[%2d]);" % (w2, w1, w0, pair[0], pair[1]))

            elif i % 2 == 0:

                print("   word3_muladd_2(&%s, &%s, &%s, x[%2d], x[%2d]);" % (w2, w1, w0, pair[0], pair[1]))

        if rnd < 2*N-2:

            print("   z[%2d] = %s; %s = 0;\n" % (rnd, w0, w0))

        else:

            print("   z[%2d] = %s;" % (rnd, w0))

        (w0,w1,w2) = (w1,w2,w0)

def main(args = None):

    if args is None:

        args = sys.argv

    if len(args) <= 1:

        sizes = [4, 6, 8, 9, 16, 24]

    else:

        sizes = map(int, args[1:])

    print("""/*

* Comba Multiplication and Squaring

* This file was automatically generated by %s on %s

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/mp_core.h>

#include <botan/internal/mp_asmi.h>

namespace Botan {

""" % (sys.argv[0], datetime.date.today().strftime("%Y-%m-%d")))

    for n in sizes:

        print("/*\n* Comba %dx%d Squaring\n*/" % (n, n))

        print("void bigint_comba_sqr%d(word z[%d], const word x[%d])" % (n, 2*n, n))

        print("   {")

        print("   word w2 = 0, w1 = 0, w0 = 0;\n")

        comba_square_code(n)

        print("   }\n")

        print("/*\n* Comba %dx%d Multiplication\n*/" % (n, n))

        print("void bigint_comba_mul%d(word z[%d], const word x[%d], const word y[%d])" % (n, 2*n, n, n))

        print("   {")

        print("   word w2 = 0, w1 = 0, w0 = 0;\n")

        comba_multiply_code(n)

        print("   }\n")

    print("}")

    return 0

if __name__ == '__main__':

    sys.exit(main())