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Annotation of 43BSDReno/kerberosIV/make_p/make_p.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * $Source: /mit/kerberos/src/lib/des/RCS/make_p.c,v $
        !             3:  * $Author: jtkohl $
        !             4:  *
        !             5:  * Copyright 1985, 1988 by the Massachusetts Institute of Technology.
        !             6:  *
        !             7:  * For copying and distribution information, please
        !             8:  * see the file <mit-copyright.h>.
        !             9:  *
        !            10:  * This routine generates the P permutation code for the DES.
        !            11:  */
        !            12: 
        !            13: #include <mit-copyright.h>
        !            14: #include <stdio.h>
        !            15: #include "des_internal.h"
        !            16: #include "tables.h"
        !            17: 
        !            18: void gen(stream)
        !            19:     FILE *stream;
        !            20: {
        !            21:     /* P permutes 32 bit input R1 into 32 bit output R2 */     
        !            22: 
        !            23:     /* clear the output */
        !            24:     fprintf(stream,"    L2 = 0;\n");
        !            25: #ifndef        BIG
        !            26:     fprintf(stream,"    R2 = 0;\n");
        !            27:     fprintf(stream,
        !            28:            "/* P operations */\n/* from right to right */\n");
        !            29:     /* first list mapping from left to left */
        !            30:     for (i = 0; i <=31; i++)
        !            31:        if (P[i] < 32)
        !            32:            fprintf(stream,
        !            33:                    "    if (R1 & (1<<%d)) R2 |= 1<<%d;\n",P[i],i);
        !            34: #else /* BIG */
        !            35:     /* flip p into p_temp */
        !            36:     fprintf(stream,"    P_temp = R1;\n");
        !            37:     fprintf(stream,"    P_temp_p = (unsigned char *) &P_temp;\n");
        !            38:  
        !            39: #ifdef LSBFIRST
        !            40:     fprintf(stream,"    R2 = P_prime[0][*P_temp_p++];\n");
        !            41:     fprintf(stream,"    R2 |= P_prime[1][*P_temp_p++];\n");
        !            42:     fprintf(stream,"    R2 |= P_prime[2][*P_temp_p++];\n");
        !            43:     fprintf(stream,"    R2 |= P_prime[3][*P_temp_p];\n");
        !            44: #else /* MSBFIRST */
        !            45:     fprintf(stream,"    R2 = P_prime[3][*P_temp_p++];\n");
        !            46:     fprintf(stream,"    R2 |= P_prime[2][*P_temp_p++];\n");
        !            47:     fprintf(stream,"    R2 |= P_prime[1][*P_temp_p++];\n");
        !            48:     fprintf(stream,"    R2 |= P_prime[0][*P_temp_p];\n");
        !            49: #endif /* MSBFIRST */
        !            50: #endif /* BIG */
        !            51: }

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