C: Bit mask question

[Bas Jacobs]

Hi folks,

Consider a control register, which includes flags and bitfields. When
writing such a register you often see constructions like register = flaga |
flagb | flagc; etc. In a library those flags are then defined as #define
flaga (1 << 6) and #define flagb (1 << 13) (for instance). In my library
there is also a definition for a bitfield, which looks something like this:
#define bitfieldA (0x0F << 16) for a 4bit bitfield located at bits 19 .. 16.
Lets say that I want write 0x6 into this field, how do I do this (using the
macro of course)?

Hope someone can help me,

Bas
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