/* * $Source: /mit/kerberos/src/lib/des/RCS/make_fp.c,v $ * $Author: jtkohl $ * * Copyright 1988 by the Massachusetts Institute of Technology. * * For copying and distribution information, * please see the file <mit-copyright.h>. * * This file contains a generation routine for source code * implementing the final permutation of the DES. */ #include <mit-copyright.h> #include <stdio.h> #include "des_internal.h" #include "tables.h" extern unsigned int swap_bit_pos_0_to_ansi PROTOTYPE((unsigned int)); extern long swap_long_bytes(); extern void test_set PROTOTYPE((FILE *, char const *, int, char const *, int)); void gen (stream) FILE * stream; { register i; /* clear the output */ fprintf(stream," L2 = 0; R2 = 0;\n"); /* * NOTE: As part of the final permutation, we also have to adjust * for host bit order via "swap_bit_pos_0()". Since L2,R2 are * the output from this, we adjust the bit positions written into * L2,R2. */ #define SWAP(i,j) \ swap_long_bytes_bit_number(swap_bit_pos_0_to_ansi((unsigned)i)-j) /* first setup FP */ fprintf(stream, "/* FP operations */\n/* first left to left */\n"); /* first list mapping from left to left */ for (i = 0; i <= 31; i++) if (FP[i] < 32) test_set(stream, "L1", FP[i], "L2", SWAP(i,0)); /* now mapping from right to left */ fprintf(stream,"\n\n/* now from right to left */\n"); for (i = 0; i <= 31; i++) if (FP[i] >= 32) test_set(stream, "R1", FP[i]-32, "L2", SWAP(i,0)); fprintf(stream,"\n/* now from left to right */\n"); /* list mapping from left to right */ for (i = 32; i <= 63; i++) if (FP[i] <32) test_set(stream, "L1", FP[i], "R2", SWAP(i,32)); /* now mapping from right to right */ fprintf(stream,"\n/* last from right to right */\n"); for (i = 32; i <= 63; i++) if (FP[i] >= 32) test_set(stream, "R1", FP[i]-32, "R2", SWAP(i,32)); }