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Diffstat (limited to 'arch/arm/include/asm/arch-sa1100/bitfield.h')
| -rw-r--r-- | arch/arm/include/asm/arch-sa1100/bitfield.h | 112 | 
1 files changed, 112 insertions, 0 deletions
| diff --git a/arch/arm/include/asm/arch-sa1100/bitfield.h b/arch/arm/include/asm/arch-sa1100/bitfield.h new file mode 100644 index 000000000..104a21c2e --- /dev/null +++ b/arch/arm/include/asm/arch-sa1100/bitfield.h @@ -0,0 +1,112 @@ +/* + *	FILE		bitfield.h + * + *	Version		1.1 + *	Author		Copyright (c) Marc A. Viredaz, 1998 + *			DEC Western Research Laboratory, Palo Alto, CA + *	Date		April 1998 (April 1997) + *	System		Advanced RISC Machine (ARM) + *	Language	C or ARM Assembly + *	Purpose		Definition of macros to operate on bit fields. + */ + + +#ifndef __BITFIELD_H +#define __BITFIELD_H + +#ifndef __ASSEMBLY__ +#define UData(Data)	((unsigned long) (Data)) +#else +#define UData(Data)	(Data) +#endif + + +/* + * MACRO: Fld + * + * Purpose + *    The macro "Fld" encodes a bit field, given its size and its shift value + *    with respect to bit 0. + * + * Note + *    A more intuitive way to encode bit fields would have been to use their + *    mask. However, extracting size and shift value information from a bit + *    field's mask is cumbersome and might break the assembler (255-character + *    line-size limit). + * + * Input + *    Size		Size of the bit field, in number of bits. + *    Shft		Shift value of the bit field with respect to bit 0. + * + * Output + *    Fld		Encoded bit field. + */ + +#define Fld(Size, Shft)	(((Size) << 16) + (Shft)) + + +/* + * MACROS: FSize, FShft, FMsk, FAlnMsk, F1stBit + * + * Purpose + *    The macros "FSize", "FShft", "FMsk", "FAlnMsk", and "F1stBit" return + *    the size, shift value, mask, aligned mask, and first bit of a + *    bit field. + * + * Input + *    Field		Encoded bit field (using the macro "Fld"). + * + * Output + *    FSize		Size of the bit field, in number of bits. + *    FShft		Shift value of the bit field with respect to bit 0. + *    FMsk		Mask for the bit field. + *    FAlnMsk		Mask for the bit field, aligned on bit 0. + *    F1stBit		First bit of the bit field. + */ + +#define FSize(Field)	((Field) >> 16) +#define FShft(Field)	((Field) & 0x0000FFFF) +#define FMsk(Field)	(((UData (1) << FSize (Field)) - 1) << FShft (Field)) +#define FAlnMsk(Field)	((UData (1) << FSize (Field)) - 1) +#define F1stBit(Field)	(UData (1) << FShft (Field)) + + +/* + * MACRO: FInsrt + * + * Purpose + *    The macro "FInsrt" inserts a value into a bit field by shifting the + *    former appropriately. + * + * Input + *    Value		Bit-field value. + *    Field		Encoded bit field (using the macro "Fld"). + * + * Output + *    FInsrt		Bit-field value positioned appropriately. + */ + +#define FInsrt(Value, Field) \ +			(UData (Value) << FShft (Field)) + + +/* + * MACRO: FExtr + * + * Purpose + *    The macro "FExtr" extracts the value of a bit field by masking and + *    shifting it appropriately. + * + * Input + *    Data		Data containing the bit-field to be extracted. + *    Field		Encoded bit field (using the macro "Fld"). + * + * Output + *    FExtr		Bit-field value. + */ + +#define FExtr(Data, Field) \ +			((UData (Data) >> FShft (Field)) & FAlnMsk (Field)) + + +#endif /* __BITFIELD_H */ |