Dr. Windows 3/dr win3.zip/dr win3/WINPROGS/WINSRC20.ZIP/MPMATH_A.ASM

Assembly Source File | 1990-01-19 | 17KB | 1,061 lines

TITLE mpmath_a.asm (C) 1989, Mark C. Peterson, CompuServe [70441,3353]
SUBTTL All rights reserved.
;
;  Code may be used in any program provided the author is credited
;    either during program execution or in the documentation.  Source
;    code may be distributed only in combination with public domain or
;    shareware source code.  Source code may be modified provided the
;    copyright notice and this message is left unchanged and all
;    modifications are clearly documented.
;
;    I would appreciate a copy of any work which incorporates this code,
;    however this is optional.
;
;    Mark C. Peterson
;    128 Hamden Ave., F
;    Waterbury, CT 06704
;    [phone]
;
;  Note: Remark statements following floating point commands generally indicate
;     the FPU stack contents after the command is completed.
;
;  References:
;     80386/80286 Assembly Language Programming
;        by William H. Murray, III and Chris H. Pappas
;        Published by Osborne McGraw-Hill, 1986
;
;
;


IFDEF ??version
MASM51
QUIRKS
EMUL
ENDIF

.model medium, c


.data

extrn cpu:WORD


MP STRUC
   Exp   DW    0
   Mant  DD    0
MP ENDS


PUBLIC MPOverflow
MPOverflow  DW        0

Ans         MP       <?>
Double      DQ        ?


.code

.8086

fg2MP086    PROC     x:DWORD, fg:WORD
   mov   ax, WORD PTR [x]
   mov   dx, WORD PTR [x+2]
   mov   cx, ax
   or    cx, dx
   jz    ExitFg2MP

   mov   cx, 1 SHL 14 + 30
   sub   cx, fg

   or    dx, dx
   jns   BitScanRight

   or    ch, 80h
   not   ax
   not   dx
   add   ax, 1
   adc   dx, 0

BitScanRight:
   shl   ax, 1
   rcl   dx, 1
   dec   cx
   or    dx, dx
   jns   BitScanRight

ExitFg2MP:
   mov   Ans.Exp, cx
   mov   WORD PTR Ans.Mant+2, dx
   mov   WORD PTR Ans.Mant, ax
   lea   ax, Ans
   mov   dx, ds
   ret
fg2MP086    ENDP



MPcmp086    PROC     uses si di, xExp:WORD, xMant:DWORD, yExp:WORD, yMant:DWORD
LOCAL Rev:WORD, Flag:WORD
   mov   Rev, 0
   mov   Flag, 0
   mov   ax, xExp
   mov   dx, WORD PTR [xMant]
   mov   si, WORD PTR [xMant+2]
   mov   bx, yExp
   mov   cx, WORD PTR [yMant]
   mov   di, WORD PTR [yMant+2]
   or    ax, ax
   jns   AtLeastOnePos

   or    bx, bx
   jns   AtLeastOnePos

   mov   Rev, 1
   and   ah, 7fh
   and   bh, 7fh

AtLeastOnePos:
   cmp   ax, bx
   jle   Cmp1

   mov   Flag, 1
   jmp   ChkRev

Cmp1:
   je    Cmp2

   mov   Flag, -1
   jmp   ChkRev

Cmp2:
   cmp   si, di
   jbe   Cmp3

   mov   Flag, 1
   jmp   ChkRev

Cmp3:
   je    Cmp4

   mov   Flag, -1
   jmp   ChkRev

Cmp4:
   cmp   dx, cx
   jbe   Cmp5

   mov   Flag, 1
   jmp   ChkRev

Cmp5:
   je    ChkRev

   mov   Flag, -1

ChkRev:
    or    Rev, 0
   jz    ExitCmp

   neg   Flag

ExitCmp:
   mov   ax, Flag
   ret
MPcmp086    ENDP






MPmul086    PROC     uses si di, xExp:WORD, xMant:DWORD, yExp:WORD, yMant:DWORD
   mov   ax, xExp
   mov   bx, yExp
   xor   ch, ch
   shl   bh, 1
   rcr   ch, 1
   shr   bh, 1
   xor   ah, ch

   sub   bx, (1 SHL 14) - 2
   add   ax, bx
   jno   NoOverflow

Overflow:
   or    WORD PTR [xMant+2], 0
   jz    ZeroAns
   or    WORD PTR [yMant+2], 0
   jz    ZeroAns

   mov   MPOverflow, 1

ZeroAns:
   xor   ax, ax
   xor   dx, dx
   mov   Ans.Exp, ax
   jmp   StoreMant

NoOverflow:
   mov   Ans.Exp, ax

   mov   si, WORD PTR [xMant+2]
   mov   bx, WORD PTR [xMant]
   mov   di, WORD PTR [yMant+2]
   mov   cx, WORD PTR [yMant]

   mov   ax, si
   or    ax, bx
   jz    ZeroAns

   mov   ax, di
   or    ax, cx
   jz    ZeroAns

   mov   ax, cx
   mul   bx
   push  dx

   mov   ax, cx
   mul   si
   push  ax
   push  dx

   mov   ax, bx
   mul   di
   push  ax
   push  dx

   mov   ax, si
   mul   di
   pop   bx
   pop   cx
   pop   si
   pop   di

   add   ax, bx
   adc   dx, 0
   pop   bx
   add   di, bx
   adc   ax, 0
   adc   dx, 0
   add   di, cx
   adc   ax, si
   adc   dx, 0

   or    dx, dx
   js    StoreMant

   shl   di, 1
   rcl   ax, 1
   rcl   dx, 1
   sub   Ans.Exp, 1
   jo    Overflow

StoreMant:
   mov   WORD PTR Ans.Mant+2, dx
   mov   WORD PTR Ans.Mant, ax

   lea   ax, Ans
   mov   dx, ds
   ret
MPmul086    ENDP



d2MP086     PROC     uses si di, x:QWORD
   mov   dx, WORD PTR [x+6]
   mov   ax, WORD PTR [x+4]
   mov   bx, WORD PTR [x+2]
   mov   cx, WORD PTR [x]
   mov   si, dx
   shl   si, 1
   or    si, bx
   or    si, ax
   or    si, dx
   or    si, cx
   jnz   NonZero

   xor   ax, ax
   xor   dx, dx
   jmp   StoreAns

NonZero:
   mov   si, dx
   shl   si, 1
   pushf
   mov   cl, 4
   shr   si, cl
   popf
   rcr   si, 1
   add   si, (1 SHL 14) - (1 SHL 10)

   mov   di, ax                           ; shl dx:ax:bx 12 bits
   mov   cl, 12
   shl   dx, cl
   shl   ax, cl
   mov   cl, 4
   shr   di, cl
   shr   bx, cl
   or    dx, di
   or    ax, bx
   stc
   rcr   dx, 1
   rcr   ax, 1

StoreAns:
   mov   Ans.Exp, si
   mov   WORD PTR Ans.Mant+2, dx
   mov   WORD PTR Ans.Mant, ax

   lea   ax, Ans
   mov   dx, ds
   ret
d2MP086     ENDP



MP2d086     PROC     uses si di, xExp:WORD, xMant:DWORD
   sub   xExp, (1 SHL 14) - (1 SHL 10)
   jo    Overflow

   mov   bx, xExp
   and   bx, 0111100000000000b
   jz    InRangeOfDouble

Overflow:
   mov   MPOverflow, 1
   xor   ax, ax
   xor   dx, dx
   xor   bx, bx
   jmp   StoreAns

InRangeOfDouble:
   mov   si, xExp
   mov   ax, si
   mov   cl, 5
   shl   si, cl
   shl   ax, 1
   rcr   si, 1

   mov   dx, WORD PTR [xMant+2]
   mov   ax, WORD PTR [xMant]
   shl   ax, 1
   rcl   dx, 1

   mov   bx, ax
   mov   di, dx
   mov   cl, 12
   shr   dx, cl
   shr   ax, cl
   mov   cl, 4
   shl   bx, cl
   shl   di, cl
   or    ax, di
   or    dx, si

StoreAns:
   mov   WORD PTR Double+6, dx
   mov   WORD PTR Double+4, ax
   mov   WORD PTR Double+2, bx
   xor   bx, bx
   mov   WORD PTR Double, bx

   lea   ax, Double
   mov   dx, ds
   ret
MP2d086     ENDP




MPadd086    PROC     uses si di, xExp:WORD, xMant:DWORD, yExp:WORD, yMant:DWORD
   mov   si, xExp
   mov   dx, WORD PTR [xMant+2]
   mov   ax, WORD PTR [xMant]

   mov   di, yExp

   mov   cx, si
   xor   cx, di
   js    Subtract
   jz    SameMag

   cmp   si, di
   jg    XisGreater

   xchg  si, di
   xchg  dx, WORD PTR [yMant+2]
   xchg  ax, WORD PTR [yMant]

XisGreater:
   mov   cx, si
   sub   cx, di
   cmp   cx, 32
   jl    ChkSixteen
   jmp   StoreAns

ChkSixteen:
   cmp   cx, 16
   jl    SixteenBitShift

   sub   cx, 16
   mov   bx, WORD PTR [yMant+2]
   shr   bx, cl
   mov   WORD PTR [yMant], bx
   mov   WORD PTR [yMant+2], 0
   jmp   SameMag

SixteenBitShift:
   mov   bx, WORD PTR [yMant+2]
   shr   WORD PTR [yMant+2], cl
   shr   WORD PTR [yMant], cl
   neg   cl
   add   cl, 16
   shl   bx, cl
   or    WORD PTR [yMant], bx

SameMag:
   add   ax, WORD PTR [yMant]
   adc   dx, WORD PTR [yMant+2]
   jc    ShiftCarry
   jmp   StoreAns

ShiftCarry:
   rcr   dx, 1
   rcr   ax, 1
   add   si, 1
   jo    Overflow
   jmp   StoreAns

Overflow:
   mov   MPOverflow, 1

ZeroAns:
   xor   si, si
   xor   ax, ax
   xor   dx, dx
   jmp   StoreAns

Subtract:
   xor   di, 8000h
   mov   cx, si
   sub   cx, di
   jnz   DifferentMag

   cmp   dx, WORD PTR [yMant+2]
   jg    SubtractNumbers
   jne   SwapNumbers

   cmp   ax, WORD PTR [yMant]
   jg    SubtractNumbers
   je    ZeroAns

SwapNumbers:
   xor   si, 8000h
   xchg  ax, WORD PTR [yMant]
   xchg  dx, WORD PTR [yMant+2]
   jmp   SubtractNumbers

DifferentMag:
   or    cx, cx
   jns   NoSwap

   xchg  si, di
   xchg  ax, WORD PTR [yMant]
   xchg  dx, WORD PTR [yMant+2]
   xor   si, 8000h
   neg   cx

NoSwap:
   cmp   cx, 32
   jge   StoreAns

   cmp   cx, 16
   jl    SixteenBitShift2

   sub   cx, 16
   mov   bx, WORD PTR [yMant+2]
   shr   bx, cl
   mov   WORD PTR [yMant], bx
   mov   WORD PTR [yMant+2], 0
   jmp   SubtractNumbers

SixteenBi