96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
/*---------------------------------------------------------------------------+
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| round_Xsig.c |
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| Copyright (C) 1992,1993,1994,1995,1999 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@melbpc.org.au |
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| Normalize and round a 12 byte quantity. |
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| int round_Xsig(Xsig *n) |
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| Normalize a 12 byte quantity. |
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| int norm_Xsig(Xsig *n) |
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| Each function returns the size of the shift (nr of bits). |
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+---------------------------------------------------------------------------*/
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#include "fpu_emu.h"
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#include "poly.h"
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int round_Xsig(Xsig *x)
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{
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int n = 0;
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if ( x->msw == 0 )
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{
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x->msw = x->midw;
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x->midw = x->lsw;
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x->lsw = 0;
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n = 32;
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}
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while ( !(x->msw & 0x80000000) )
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{
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x->msw <<= 1;
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if ( x->midw & 0x80000000 ) x->msw |= 1;
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x->midw <<= 1;
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if ( x->lsw & 0x80000000 ) x->midw |= 1;
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x->lsw <<= 1;
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n++;
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}
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if ( x->lsw & 0x80000000 )
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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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if ( x->msw == 0 )
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{
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x->msw = 0x80000000;
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n--;
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}
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}
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return -n;
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}
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int norm_Xsig(Xsig *x)
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{
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int n = 0;
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if ( x->msw == 0 )
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{
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if ( x->midw == 0 )
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{
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x->msw = x->lsw;
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x->midw = 0;
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x->lsw = 0;
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n = 64;
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}
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else
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{
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x->msw = x->midw;
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x->midw = x->lsw;
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x->lsw = 0;
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n = 32;
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}
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}
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while ( !(x->msw & 0x80000000) )
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{
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x->msw <<= 1;
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if ( x->midw & 0x80000000 ) x->msw |= 1;
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x->midw <<= 1;
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if ( x->lsw & 0x80000000 ) x->midw |= 1;
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x->lsw <<= 1;
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n++;
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}
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return -n;
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}
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