patch-2.4.0-test5 linux/include/asm-arm/arch-sa1100/bitfield.h

• Lines: 124
• Date: Tue Jul 18 22:43:25 2000
• Orig file: v2.4.0-test4/linux/include/asm-arm/arch-sa1100/bitfield.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test4/linux/include/asm-arm/arch-sa1100/bitfield.h linux/include/asm-arm/arch-sa1100/bitfield.h
@@ -0,0 +1,123 @@
+/*
+ *	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
+#define BITFIELD
+
+#ifndef LANGUAGE
+#define LANGUAGE	C
+#endif /* !defined (LANGUAGE) */
+
+#define C       	0
+#define Assembly	1
+
+#if LANGUAGE == C
+#define UData(Data)	((unsigned int) (Data))
+#elif LANGUAGE == Assembly
+#define UData(Data)	(Data)
+#endif /* LANGUAGE == C || LANGUAGE == Assembly */
+
+
+/*
+ * 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))
+
+
+#undef C
+#undef Assembly
+
+#endif /* !defined (BITFIELD) */