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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [i386/] [math-emu/] [polynom_Xsig.S] - Blame information for rev 1782

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Line No. Rev Author Line
1 1623 jcastillo
/*---------------------------------------------------------------------------+
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 |  polynomial_Xsig.S                                                        |
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 |                                                                           |
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 | Fixed point arithmetic polynomial evaluation.                             |
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 |                                                                           |
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 | Copyright (C) 1992,1993,1994,1995                                         |
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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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 |                                                                           |
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 | Call from C as:                                                           |
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 |   void polynomial_Xsig(Xsig *accum, unsigned long long x,                 |
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 |                        unsigned long long terms[], int n)                 |
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 |                                                                           |
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 | Computes:                                                                 |
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 | terms[0] + (terms[1] + (terms[2] + ... + (terms[n-1]*x)*x)*x)*x) ... )*x  |
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 | and adds the result to the 12 byte Xsig.                                  |
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 | The terms[] are each 8 bytes, but all computation is performed to 12 byte |
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 | precision.                                                                |
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 |                                                                           |
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 | This function must be used carefully: most overflow of intermediate       |
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 | results is controlled, but overflow of the result is not.                 |
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 |                                                                           |
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 +---------------------------------------------------------------------------*/
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        .file   "polynomial_Xsig.S"
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#include "fpu_emu.h"
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#define TERM_SIZE       $8
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#define SUM_MS          -20(%ebp)       /* sum ms long */
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#define SUM_MIDDLE      -24(%ebp)       /* sum middle long */
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#define SUM_LS          -28(%ebp)       /* sum ls long */
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#define ACCUM_MS        -4(%ebp)        /* accum ms long */
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#define ACCUM_MIDDLE    -8(%ebp)        /* accum middle long */
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#define ACCUM_LS        -12(%ebp)       /* accum ls long */
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#define OVERFLOWED      -16(%ebp)       /* addition overflow flag */
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.text
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ENTRY(polynomial_Xsig)
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        pushl   %ebp
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        movl    %esp,%ebp
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        subl    $32,%esp
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        pushl   %esi
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        pushl   %edi
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        pushl   %ebx
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        movl    PARAM2,%esi             /* x */
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        movl    PARAM3,%edi             /* terms */
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        movl    TERM_SIZE,%eax
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        mull    PARAM4                  /* n */
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        addl    %eax,%edi
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        movl    4(%edi),%edx            /* terms[n] */
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        movl    %edx,SUM_MS
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        movl    (%edi),%edx             /* terms[n] */
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        movl    %edx,SUM_MIDDLE
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        xor     %eax,%eax
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        movl    %eax,SUM_LS
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        movb    %al,OVERFLOWED
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        subl    TERM_SIZE,%edi
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        decl    PARAM4
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        js      L_accum_done
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L_accum_loop:
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        xor     %eax,%eax
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        movl    %eax,ACCUM_MS
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        movl    %eax,ACCUM_MIDDLE
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        movl    SUM_MIDDLE,%eax
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        mull    (%esi)                  /* x ls long */
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        movl    %edx,ACCUM_LS
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        movl    SUM_MIDDLE,%eax
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        mull    4(%esi)                 /* x ms long */
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        addl    %eax,ACCUM_LS
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        adcl    %edx,ACCUM_MIDDLE
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        adcl    $0,ACCUM_MS
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        movl    SUM_MS,%eax
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        mull    (%esi)                  /* x ls long */
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        addl    %eax,ACCUM_LS
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        adcl    %edx,ACCUM_MIDDLE
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        adcl    $0,ACCUM_MS
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        movl    SUM_MS,%eax
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        mull    4(%esi)                 /* x ms long */
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        addl    %eax,ACCUM_MIDDLE
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        adcl    %edx,ACCUM_MS
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        testb   $0xff,OVERFLOWED
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        jz      L_no_overflow
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        movl    (%esi),%eax
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        addl    %eax,ACCUM_MIDDLE
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        movl    4(%esi),%eax
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        adcl    %eax,ACCUM_MS           /* This could overflow too */
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L_no_overflow:
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/*
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 * Now put the sum of next term and the accumulator
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 * into the sum register
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 */
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        movl    ACCUM_LS,%eax
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        addl    (%edi),%eax             /* term ls long */
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        movl    %eax,SUM_LS
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        movl    ACCUM_MIDDLE,%eax
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        adcl    (%edi),%eax             /* term ls long */
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        movl    %eax,SUM_MIDDLE
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        movl    ACCUM_MS,%eax
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        adcl    4(%edi),%eax            /* term ms long */
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        movl    %eax,SUM_MS
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        sbbb    %al,%al
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        movb    %al,OVERFLOWED          /* Used in the next iteration */
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        subl    TERM_SIZE,%edi
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        decl    PARAM4
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        jns     L_accum_loop
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L_accum_done:
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        movl    PARAM1,%edi             /* accum */
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        movl    SUM_LS,%eax
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        addl    %eax,(%edi)
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        movl    SUM_MIDDLE,%eax
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        adcl    %eax,4(%edi)
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        movl    SUM_MS,%eax
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        adcl    %eax,8(%edi)
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        popl    %ebx
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        popl    %edi
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        popl    %esi
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        leave
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        ret

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