C Bitfields

[Mark Newman]

Thanks Tom!

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Mark Newman

[Tom Hanlin]

Looks good to me.

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Tom Hanlin
PowerBASIC Staff

[Mark Newman]

I have a a C bifield to port:

typedef struct BIT_FIELD_STRUCT
{
   ULONG b1 : 4;     // bits[3:0]
   ULONG b2 : 4;
   ULONG b3 : 4;
   ULONG b4 : 4;
   ULONG b5 : 4;
   ULONG b6 : 4;
   ULONG b7 : 4;
   ULONG b8 : 4;     // bits[31:28]
} BIT_FIELD;

My C book tells me that C compiles bitfields into a contiguous stream of bits
regardless of the member type declaration, so the port to PB would seem to be:

TYPE BIT_FIELD
   BitField    as DWORD
END TYPE

I presume that I port C code like:

   ABitField.b1 = 0x09

over to PB as:

   ABitField.BitField = ABitField.BitField AND &HFFFFFFF0   ' Clear the lowest 4 bits
   ABitField.BitField = ABitField.BitField OR &H09          ' Set the lower 4 bits to the new value

Look right?

Thanks!

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Mark Newman

[This message has been edited by Mark Newman (edited May 01, 2001).]