142 lines
3.6 KiB
ArmAsm
142 lines
3.6 KiB
ArmAsm
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/*---------------------------------------------------------------------------+
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| polynomial.S |
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| Fixed point arithmetic polynomial evaluation. |
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| Copyright (C) 1992,1993 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@vaxc.cc.monash.edu.au |
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| Call from C as: |
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| void polynomial(unsigned accum[], unsigned x[], unsigned terms[][2], |
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| int n) |
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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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| The result is returned in accum. |
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+---------------------------------------------------------------------------*/
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.file "fpolynom.s"
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#include "fpu_asm.h"
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/* #define EXTRA_PRECISE // Do not use: not complete */
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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 SUM_LS_HI -25(%ebp) /* high byte of sum ls */
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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 ACCUM_LS_HI -9(%ebp) /* high byte of accum ls */
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.text
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.align 2,144
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.globl _polynomial
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_polynomial:
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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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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 %eax,-16(%ebp) // Not needed */
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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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/*
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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_MIDDLE,%eax
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addl (%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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#ifdef EXTRA_PRECISE
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movl ACCUM_LS,%eax
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movl %eax,SUM_LS
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#else
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testb $0x80,ACCUM_LS_HI /* ms bit of ACCUM_LS */
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je L_no_poly_round
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addl $1,SUM_MIDDLE
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adcl $0,SUM_MS
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L_no_poly_round:
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#endif EXTRA_PRECISE
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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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#ifdef EXTRA_PRECISE
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/* Round the result */
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testb $128,SUM_LS_HI
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je L_poly_done
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addl $1,SUM_MIDDLE
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adcl $0,SUM_MS
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#endif EXTRA_PRECISE
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L_poly_done:
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movl PARAM1,%edi /* accum */
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movl SUM_MIDDLE,%eax
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movl %eax,(%edi)
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movl SUM_MS,%eax
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movl %eax,4(%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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