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Annotation of pgp/src/lmul.h, revision 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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