bldun Struct Reference

Public Attributes
union {
wxByte   by [sizeof(wxFloat64)/sizeof(wxByte)]
wxUint32   fl [sizeof(wxFloat64)/sizeof(wxUint32)]
wxFloat64   machdb
};

Detailed Description

PC double union

To convert GDSII doubles to machine doubles : void gds_double( fb)

To convert machine doubles to GDSII doubles : void double_gds( fb)

GDSII floating point representation (8-byte REAL)

SEEEEEEE MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM

Sign = S=1 negatif S=0 positif Expo = (E-64)^16 Mantisse = (1/16 <= M < 1) Double value = (-1)^S * Expo * Mantisse Zero = all bits of M zero

unix (Apollo) or wxBIG_ENDIAN (8-byte REAL)

SEEEEEEE EEEEMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM

Sign = S=1 negatif S=0 positif Expo = (E-1023)^2 Mantisse = (1.M)binary Double value = (-1)^S * Expo * Mantisse Zero = E=0 and M=0 +-Infinit = E=2047 and M=0

notice: a wxUint32 in turbo C = in memory for instance like this m=40 m+1=99 m+2=94 m+3=93

then (long) & 0xFF000000 gives the result m=40 m+1=99 m+2=94 m+3=00

in most other machine this is m=00 m+1=99 m+2=94 m+3=93

all of this is due to that the bytes of types are in reverse order in memory.

Definition at line 270 of file gdsio.cpp.

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The documentation for this struct was generated from the following file:

• gdsio.cpp