/*
 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * The new form of this macro (check if the a*b == 0) was suggested by Colin
 * Plumb <colin@nyx10.cs.du.edu>
 */
/* Removal of the inner if from from Wei Dai 24/4/96 */
#define idea_mul(r,a,b,ul) \
ul=(unsigned long)a*b; \
if (ul != 0) \
        { \
        r=(ul&0xffff)-(ul>>16); \
        r-=((r)>>16); \
        } \
else \
        r=(-(int)a-b+1);        /* assuming a or b is 0 and in range */

/*
 * 7/12/95 - Many thanks to Rhys Weatherley <rweather@us.oracle.com> for
 * pointing out that I was assuming little endian byte order for all
 * quantities what idea actually used bigendian.  No where in the spec does
 * it mention this, it is all in terms of 16 bit numbers and even the example
 * does not use byte streams for the input example :-(. If you byte swap each
 * pair of input, keys and iv, the functions would produce the output as the
 * old version :-(.
 */

/* NOTE - c is not incremented as per n2l */
#define n2ln(c,l1,l2,n) { \
                        c+=n; \
                        l1=l2=0; \
                        switch (n) { \
                        case 8: l2 =((unsigned long)(*(--(c))))    ; \
                        /* fall thru */                              \
                        case 7: l2|=((unsigned long)(*(--(c))))<< 8; \
                        /* fall thru */                              \
                        case 6: l2|=((unsigned long)(*(--(c))))<<16; \
                        /* fall thru */                              \
                        case 5: l2|=((unsigned long)(*(--(c))))<<24; \
                        /* fall thru */                              \
                        case 4: l1 =((unsigned long)(*(--(c))))    ; \
                        /* fall thru */                              \
                        case 3: l1|=((unsigned long)(*(--(c))))<< 8; \
                        /* fall thru */                              \
                        case 2: l1|=((unsigned long)(*(--(c))))<<16; \
                        /* fall thru */                              \
                        case 1: l1|=((unsigned long)(*(--(c))))<<24; \
                                } \
                        }

/* NOTE - c is not incremented as per l2n */
#define l2nn(l1,l2,c,n) { \
                        c+=n; \
                        switch (n) { \
                        case 8: *(--(c))=(unsigned char)(((l2)    )&0xff); \
                        /* fall thru */                                    \
                        case 7: *(--(c))=(unsigned char)(((l2)>> 8)&0xff); \
                        /* fall thru */                                    \
                        case 6: *(--(c))=(unsigned char)(((l2)>>16)&0xff); \
                        /* fall thru */                                    \
                        case 5: *(--(c))=(unsigned char)(((l2)>>24)&0xff); \
                        /* fall thru */                                    \
                        case 4: *(--(c))=(unsigned char)(((l1)    )&0xff); \
                        /* fall thru */                                    \
                        case 3: *(--(c))=(unsigned char)(((l1)>> 8)&0xff); \
                        /* fall thru */                                    \
                        case 2: *(--(c))=(unsigned char)(((l1)>>16)&0xff); \
                        /* fall thru */                                    \
                        case 1: *(--(c))=(unsigned char)(((l1)>>24)&0xff); \
                                } \
                        }

#undef n2l
#define n2l(c,l)        (l =((unsigned long)(*((c)++)))<<24L, \
                         l|=((unsigned long)(*((c)++)))<<16L, \
                         l|=((unsigned long)(*((c)++)))<< 8L, \
                         l|=((unsigned long)(*((c)++))))

#undef l2n
#define l2n(l,c)        (*((c)++)=(unsigned char)(((l)>>24L)&0xff), \
                         *((c)++)=(unsigned char)(((l)>>16L)&0xff), \
                         *((c)++)=(unsigned char)(((l)>> 8L)&0xff), \
                         *((c)++)=(unsigned char)(((l)     )&0xff))

#undef s2n
#define s2n(l,c)        (*((c)++)=(unsigned char)(((l)     )&0xff), \
                         *((c)++)=(unsigned char)(((l)>> 8L)&0xff))

#undef n2s
#define n2s(c,l)        (l =((IDEA_INT)(*((c)++)))<< 8L, \
                         l|=((IDEA_INT)(*((c)++)))      )


#define E_IDEA(num) \
        x1&=0xffff; \
        idea_mul(x1,x1,*p,ul); p++; \
        x2+= *(p++); \
        x3+= *(p++); \
        x4&=0xffff; \
        idea_mul(x4,x4,*p,ul); p++; \
        t0=(x1^x3)&0xffff; \
        idea_mul(t0,t0,*p,ul); p++; \
        t1=(t0+(x2^x4))&0xffff; \
        idea_mul(t1,t1,*p,ul); p++; \
        t0+=t1; \
        x1^=t1; \
        x4^=t0; \
        ul=x2^t0; /* do the swap to x3 */ \
        x2=x3^t1; \
        x3=ul;
