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Annotation of pgp/src/lmul.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * lmul.h  - Macros for doing a n x n -> 2N multiply.
                      3:  *
                      4:  * Included by R3000.C, for use in Philip Zimmermann's PGP program.
                      5:  * Implemented by Castor Fu, Sep 1992.
                      6:  *
                      7:  * Define PATCH_ASM if you want to patch the assembly code yourself. . .
                      8:  *
                      9:  * Currently has support for mips, i386 and 680[2+]0 under GCC.
                     10:  *
                     11:  * The general (and generally undesired ) case manually
                     12:  * performs the multiply by splitting the numbers up into two pieces. . .
                     13:  *
                     14:  * lmul(i1,i2,ol,oh) takes the product of i1, i2 and yields ol, oh
                     15:  * the lower and upper halves of the result.
                     16:  */
                     17: 
                     18: #ifdef PATCH_ASM
                     19: #define        lmul(i1,i2,ol, oh)      (ol=(i1)*(i2), oh=(i1)^(i2))
                     20: #else
                     21: 
                     22: #if    defined(__GNUC__) && defined(mips)  && defined(MUNIT32)
                     23: #define lmul(a,b,xl,xh) \
                     24: { \
                     25:        asm("multu      %2, %3\n\tmflo  %0\n\tmfhi      %1" : \
                     26:                "=d" (xl) , "=d" (xh) : "d" (a), "d" (b)); \
                     27: }
                     28: #else 
                     29: #if    defined(__GNUC__) && defined(mc68020)  && defined(MUNIT32)
                     30: #define        lmul(a,b,xl,xh) \
                     31: {\
                     32:        xl = a; \
                     33:        asm("mulul      %3, %1:%0" : "=d" (xl) , "=d" (xh) : "0" (xl) , "d" (b)); \
                     34: }
                     35: #else
                     36: #if    defined(__GNUC__) && defined(i386)  && defined(MUNIT32)
                     37: #define        lmul(a,b,xl,xh) asm("mull %3":"=a" (xl),"=d" (xh):"0" (a),"g" (b))
                     38: #else
                     39: 
                     40: #define MUNITHMASK     (((unsigned long)1 <<(MUNITSIZE/2)) - 1)
                     41: 
                     42: #ifdef MUNIT16 
                     43: #define lmul(a,b,xl,xh) \
                     44: {\
                     45:        unsigned long XX = (unsigned long) (a)*(b); \
                     46:        xl = XX & 0xffff; \
                     47:        xh = XX >> 16; \
                     48: }
                     49: 
                     50: #else 
                     51: #define        lmul(a,b,xl, xh)  \
                     52: {\
                     53:    MULTUNIT Xaa, Xbb, Xal, Xah, Xbl, Xbh, Xx1,Xx2,Xx3,Xx4,Xx5,Xx6; \
                     54:      Xaa= (a); Xbb = (b); Xal = Xaa&MUNITHMASK; Xah = Xaa>>(MUNITSIZE/2); \
                     55:      Xbl = Xbb&MUNITHMASK; Xbh = Xbb>>(MUNITSIZE/2); \
                     56:        Xx1 = Xal*Xbl; \
                     57:        Xx2 = Xah*Xbl; \
                     58:        Xx3 = Xal*Xbh; \
                     59:        Xx4 = Xah*Xbh; \
                     60:        Xx5 = Xx2+Xx3; \
                     61:        Xx4 += ((MULTUNIT) (Xx5 < Xx2)) << (MUNITSIZE/2); \
                     62:        Xx6 = Xx1 + (Xx5 << (MUNITSIZE/2)); \
                     63:        Xx4 += (Xx6 < Xx1) + (Xx5>>(MUNITSIZE/2)); \
                     64:  \
                     65:  \
                     66:        xl = Xx6; \
                     67:        xh = Xx4; \
                     68: }
                     69: #endif
                     70: #endif
                     71: #endif
                     72: #endif
                     73: #endif /* PATCH_ASM */

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