CD ROM Paradise Collection 4/CD ROM Paradise Collection 4 1995 Nov.iso/program/swagd_f.zip/DATETIME.SWG/0020_UNIXTIME.PAS.pas

Pascal/Delphi Source File | 1993-05-28 | 4KB | 204 lines

{
INBAR RAZ

I just happen to have Programmed such a thing, For a certain Program. It's not
perfect, in the essence that It will produce good results only from 1970 to
2099, because I didn't feel like starting to investigate which are leap years
and which are not. All the leap years between 1970 and 2099 ARE included,
though.

This Procedure returns a LongInt UNIX-like timestamp. TimeRec will be
overwritten by the resulted UNSIGNED DWord.
}

Procedure SecondSince1970(Year, Month, Day, Hour, Minute : Word; Var TimeRec);

Var
  T_Lo,
  T_Hi  : Word;

begin
  Asm

    Call @Table

   @Table:

    Pop Si
    Add Si,6            { Point Si to data table }
    Jmp @Compute

    { This table contains the number of days in all months Until this one }

    dw  0               { Within January }
    dw  31              { January }
    dw  59              { February }
    dw  90              { Mars }
    dw  120             { April }
    dw  151             { May }
    dw  181             { June }
    dw  212             { July }
    dw  243             { August }
    dw  273             { September }
    dw  304             { October }
    dw  334             { November }

    { This i a routine to multiply a DWord by a Word }
    { Input: DX:AX Word to multilpy, CX multiplier }

   @Calc:

    Push Si
    Push Di

    Mov Di,Dx
    Mov Si,Ax

    Dec Cx              { We already have it multiplied by 1 }

   @Addit:

    Add Ax,Si
    Adc Dx,Di

    Loop @Addit

    Pop Di
    Pop Si

    Ret

   @Compute:

    Xor Di,Di           { Variable For leap year }

    { Seconds of round years }

    Mov Bx,Year
    Sub Bx,1970
    Mov Ax,365*24       { Hours per year }
    Mov Cx,60*60        { Seconds per hour }
    Xor Dx,Dx

    Call @Calc          { Multiply dWord response by CX }
    Mov Cx,Bx
    Call @Calc

    Push Ax
    Push Dx

    { Seconds of leap years }

    Mov Ax,Year
    Sub Ax,1972         { First leap year after 1972 }
    Mov Bx,4
    Xor Dx,Dx
    Div Bx

    { DX now holds number of days to add becaues of leap years. }
    { if DX is 0, this is a leap year, and we need to take it into
      conideration }

    Mov Di,Dx          { if DI is 0, this is a leap year }

    Inc Ax             { We must count 1972 as well }
    Xor Dx,Dx
    Mov Bx,60*60
    Mov Cx,24

    Mul Bx
    Call @Calc

    Mov Cx,Dx
    Mov Bx,Ax

    { Now add what we had before }

    Pop Dx
    Pop Ax

    Add Ax,Bx
    Adc Dx,Cx

    Push Ax
    Push Dx

    { DX:AX holds the number of seconds since 1970 till the beginning of year}

    { Add days Within this year }

    Mov Bx,Month
    Dec Bx
    Shl Bx,1
    Add Bx,Si
    Mov Bx,cs:[Bx]      { Lookup Table, sum of months EXCEPT this one }
    Add Bx,Day          { Add days Within this one }
    Dec Bx              { Today hasn't ended yet }

    Mov Ax,60*60
    Mov Cx,24
    Xor Dx,Dx
    Mul Bx
    Call @Calc

    Mov Cx,Dx
    Mov Bx,Ax

    { Now add what we had before - days Until beginning of the year }

    Pop Dx
    Pop Ax

    Add Ax,Bx
    Adc Dx,Cx

    { DX:AX now holds the number of seconds since 1970 till beginning of day.}

    Push Ax
    Push Dx

    { DX:AX holds the number of seconds Until the beginning of this day }

    Mov Bx,Hour
    Mov Ax,60*60   { Seconds per hour }
    Xor Dx,Dx
    Mul Bx

    Push Ax
    Push Dx

    Mov Bx,Minute
    Mov Ax,60      { Seconds per minute }
    Xor Dx,Dx
    Mul Bx

    Mov Cx,Dx
    Mov Bx,Ax

    Pop Dx
    Pop Ax

    Add Bx,Ax
    Adc Cx,Dx

    { And add the seconds Until beginning of year }

    Pop Dx
    Pop Ax

    Add Ax,Bx
    Adc Dx,Cx

    { DX:AX now holds number of second since 1970 }

    Mov T_Hi,Dx
    Mov T_Lo,Ax

  end;

  Move(Mem[Seg(T_Lo) : Ofs(T_Lo)], Mem[Seg(TimeRec) : Ofs(TimeRec)], 2);

  Move(Mem[Seg(T_Hi) : Ofs(T_Hi)], Mem[Seg(TimeRec) : Ofs(TimeRec) + 2], 2);

end;