diff options
Diffstat (limited to 'arch/x86/math-emu/polynom_Xsig.S')
| -rw-r--r-- | arch/x86/math-emu/polynom_Xsig.S | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/arch/x86/math-emu/polynom_Xsig.S b/arch/x86/math-emu/polynom_Xsig.S new file mode 100644 index 000000000..604f0b2d1 --- /dev/null +++ b/arch/x86/math-emu/polynom_Xsig.S @@ -0,0 +1,137 @@ +/* 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) |