96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
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/*---------------------------------------------------------------------------+
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| mul_Xsig.S |
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| Multiply a 12 byte fixed point number by another fixed point number. |
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| Copyright (C) 1992,1994,1995 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@jacobi.maths.monash.edu.au |
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| The result is neither rounded nor normalized, and the ls bit or so may |
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| be wrong. |
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+---------------------------------------------------------------------------*/
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#include "fpu_emu.h"
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#include "poly.h"
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void mul32_Xsig(Xsig *x, const u32 ba)
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{
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Xsig y;
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u32 zl;
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u64 b = ba, z;
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z = b * x->lsw;
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y.lsw = z >> 32;
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z = b * x->midw;
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y.midw = z >> 32;
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zl = z;
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y.lsw += zl;
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if ( zl > y.lsw )
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y.midw ++;
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z = b * x->msw;
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y.msw = z >> 32;
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zl = z;
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y.midw += zl;
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if ( zl > y.midw )
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y.msw ++;
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*x = y;
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}
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void mul64_Xsig(Xsig *x, const u64 *b)
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{
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Xsig yh, yl;
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yh = *x;
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yl = *x;
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mul32_Xsig(&yh, (*b) >> 32);
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mul32_Xsig(&yl, *b);
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x->msw = yh.msw;
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x->midw = yh.midw + yl.msw;
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if ( yh.midw > x->midw )
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x->msw ++;
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x->lsw = yh.lsw + yl.midw;
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if ( yh.lsw > x->lsw )
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{
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x->midw ++;
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if ( x->midw == 0 )
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x->msw ++;
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}
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}
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void mul_Xsig_Xsig(Xsig *x, const Xsig *b)
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{
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u32 yh;
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u64 y, z;
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y = b->lsw;
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y *= x->msw;
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yh = y >> 32;
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z = b->msw;
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z <<= 32;
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z += b->midw;
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mul64_Xsig(x, &z);
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x->lsw += yh;
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if ( yh > x->lsw )
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{
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x->midw ++;
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if ( x->midw == 0 )
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x->msw ++;
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}
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}
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