diff options
author | Ben Dooks <ben-linux@fluff.org> | 2008-08-08 21:10:12 +0100 |
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committer | Ben Dooks <ben-linux@fluff.org> | 2008-08-08 21:10:12 +0100 |
commit | af7a535688a758d15f06a98833e6a143b29af9de (patch) | |
tree | bac5ab210bbbbe276f0e44ed84194d7c8bb16aae /arch/arm/mach-sa1100/include/mach/bitfield.h | |
parent | 0c17e4ceedd35c78b1c7413dbd16279a350be6bc (diff) | |
parent | c41107c2d4fd31924533f4dbc4c3428acc2b5894 (diff) |
Merge http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm into for-rmk
Diffstat (limited to 'arch/arm/mach-sa1100/include/mach/bitfield.h')
-rw-r--r-- | arch/arm/mach-sa1100/include/mach/bitfield.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/include/mach/bitfield.h b/arch/arm/mach-sa1100/include/mach/bitfield.h new file mode 100644 index 00000000000..f1f0e3387d9 --- /dev/null +++ b/arch/arm/mach-sa1100/include/mach/bitfield.h @@ -0,0 +1,113 @@ +/* + * 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 */ |