OpenEuphoria

Re: Structures and eraier Windows graphics

• Posted by Ad Rienks <Ad_Rienks at COMPUSERVE.COM> Nov 11, 1997
• 590 views

>Jeff Fielding wrote:

>> My problem is that in struct.e, I need to know how to poke
>shorys, > ints, > and longs, and chars into memory. I need to
>know the format. If anyone > has > any ideas, please tell me and
>I'll post my files on the Offical > Euphoria > Programming
>Page.

>Ints have to be converted to 4 bytes/atom values between 0 en
>255 Longs have to be converted to 8 bytes/atom values between 0
>en 255 Chars have to be converted to 1 byte. (so just poke it
>in)

>To convert an atom to 4-bytes:     poke(addres, {a, a/2^8,
>a/2^16, a/2^24})

>2^8 means 2 to the power of 8. See the logic ?? BTW for poking
>an atom as an 4-byte machine integer, you can use some inbuilt
>routine called poke4 or something. It is a new routine for
>Euphoria 2. It is a lot faster (i suppose)

>BTW 2 you needed to convert anything to poke a char, it is
>automatically done...     poke (addres, char) works, just as    =

>poke (addres, "ralf") works fine..

>Euphoria converts stuff being poked to memory to an byte/char as
>default.

>Ralf N. nieuwen at xs4all.nl

Additional information:

For converting to 8 bytes you can use:
Command: atom_to_float64
  =

Syntax: =

  include machine.e
  s =3D atom_to_float64(a1)
  =

Description: =

  Convert a Euphoria atom to a sequence of 8 single-byte values.
  These 8 bytes contain the representation of an IEEE floating-
  point number in 64-bit format.
  =

Comments: =

  All Euphoria atoms have values which can be represented as =

  64-bit IEEE floating-point numbers, so you can convert any atom
  to 64-bit format without losing any precision. =

  =

  Integer values will also be converted to 64-bit floating-point =

  format.
  =

Example: =

     fn =3D open("numbers.dat", "wb")
      puts(fn, atom_to_float32(157.82)) -- write 8 bytes to a file
      =

See Also: =

  atom_to_float32, float64_to_atom

Ad_Rienks at compuserve.com