1 files changed, 135 insertions, 0 deletions

diff --git a/arch/i386/math-emu/polynom_Xsig.S b/arch/i386/math-emu/polynom_Xsig.S
new file mode 100644
index 000000000000..17315c89ff3d
--- /dev/null
+++ b/arch/i386/math-emu/polynom_Xsig.S
@@ -0,0 +1,135 @@
+/*---------------------------------------------------------------------------+
+ |  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