138 lines
3.9 KiB
ArmAsm
138 lines
3.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*---------------------------------------------------------------------------+
|
|
| polynomial_Xsig.S |
|
|
| |
|
|
| Fixed point arithmetic polynomial evaluation. |
|
|
| |
|
|
| Copyright (C) 1992,1993,1994,1995 |
|
|
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
|
|
| Australia. E-mail billm@jacobi.maths.monash.edu.au |
|
|
| |
|
|
| Call from C as: |
|
|
| void polynomial_Xsig(Xsig *accum, unsigned long long x, |
|
|
| unsigned long long terms[], int n) |
|
|
| |
|
|
| Computes: |
|
|
| terms[0] + (terms[1] + (terms[2] + ... + (terms[n-1]*x)*x)*x)*x) ... )*x |
|
|
| and adds the result to the 12 byte Xsig. |
|
|
| The terms[] are each 8 bytes, but all computation is performed to 12 byte |
|
|
| precision. |
|
|
| |
|
|
| This function must be used carefully: most overflow of intermediate |
|
|
| results is controlled, but overflow of the result is not. |
|
|
| |
|
|
+---------------------------------------------------------------------------*/
|
|
.file "polynomial_Xsig.S"
|
|
|
|
#include "fpu_emu.h"
|
|
|
|
|
|
#define TERM_SIZE $8
|
|
#define SUM_MS -20(%ebp) /* sum ms long */
|
|
#define SUM_MIDDLE -24(%ebp) /* sum middle long */
|
|
#define SUM_LS -28(%ebp) /* sum ls long */
|
|
#define ACCUM_MS -4(%ebp) /* accum ms long */
|
|
#define ACCUM_MIDDLE -8(%ebp) /* accum middle long */
|
|
#define ACCUM_LS -12(%ebp) /* accum ls long */
|
|
#define OVERFLOWED -16(%ebp) /* addition overflow flag */
|
|
|
|
.text
|
|
ENTRY(polynomial_Xsig)
|
|
pushl %ebp
|
|
movl %esp,%ebp
|
|
subl $32,%esp
|
|
pushl %esi
|
|
pushl %edi
|
|
pushl %ebx
|
|
|
|
movl PARAM2,%esi /* x */
|
|
movl PARAM3,%edi /* terms */
|
|
|
|
movl TERM_SIZE,%eax
|
|
mull PARAM4 /* n */
|
|
addl %eax,%edi
|
|
|
|
movl 4(%edi),%edx /* terms[n] */
|
|
movl %edx,SUM_MS
|
|
movl (%edi),%edx /* terms[n] */
|
|
movl %edx,SUM_MIDDLE
|
|
xor %eax,%eax
|
|
movl %eax,SUM_LS
|
|
movb %al,OVERFLOWED
|
|
|
|
subl TERM_SIZE,%edi
|
|
decl PARAM4
|
|
js L_accum_done
|
|
|
|
L_accum_loop:
|
|
xor %eax,%eax
|
|
movl %eax,ACCUM_MS
|
|
movl %eax,ACCUM_MIDDLE
|
|
|
|
movl SUM_MIDDLE,%eax
|
|
mull (%esi) /* x ls long */
|
|
movl %edx,ACCUM_LS
|
|
|
|
movl SUM_MIDDLE,%eax
|
|
mull 4(%esi) /* x ms long */
|
|
addl %eax,ACCUM_LS
|
|
adcl %edx,ACCUM_MIDDLE
|
|
adcl $0,ACCUM_MS
|
|
|
|
movl SUM_MS,%eax
|
|
mull (%esi) /* x ls long */
|
|
addl %eax,ACCUM_LS
|
|
adcl %edx,ACCUM_MIDDLE
|
|
adcl $0,ACCUM_MS
|
|
|
|
movl SUM_MS,%eax
|
|
mull 4(%esi) /* x ms long */
|
|
addl %eax,ACCUM_MIDDLE
|
|
adcl %edx,ACCUM_MS
|
|
|
|
testb $0xff,OVERFLOWED
|
|
jz L_no_overflow
|
|
|
|
movl (%esi),%eax
|
|
addl %eax,ACCUM_MIDDLE
|
|
movl 4(%esi),%eax
|
|
adcl %eax,ACCUM_MS /* This could overflow too */
|
|
|
|
L_no_overflow:
|
|
|
|
/*
|
|
* Now put the sum of next term and the accumulator
|
|
* into the sum register
|
|
*/
|
|
movl ACCUM_LS,%eax
|
|
addl (%edi),%eax /* term ls long */
|
|
movl %eax,SUM_LS
|
|
movl ACCUM_MIDDLE,%eax
|
|
adcl (%edi),%eax /* term ls long */
|
|
movl %eax,SUM_MIDDLE
|
|
movl ACCUM_MS,%eax
|
|
adcl 4(%edi),%eax /* term ms long */
|
|
movl %eax,SUM_MS
|
|
sbbb %al,%al
|
|
movb %al,OVERFLOWED /* Used in the next iteration */
|
|
|
|
subl TERM_SIZE,%edi
|
|
decl PARAM4
|
|
jns L_accum_loop
|
|
|
|
L_accum_done:
|
|
movl PARAM1,%edi /* accum */
|
|
movl SUM_LS,%eax
|
|
addl %eax,(%edi)
|
|
movl SUM_MIDDLE,%eax
|
|
adcl %eax,4(%edi)
|
|
movl SUM_MS,%eax
|
|
adcl %eax,8(%edi)
|
|
|
|
popl %ebx
|
|
popl %edi
|
|
popl %esi
|
|
leave
|
|
ret
|
|
ENDPROC(polynomial_Xsig)
|