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19025d77ad
Reorganized. Created a new top level include directory that will hold all of Trick's header files. Moved all of the Trick headers to this directory. Created a libexec directory that holds all of the executables that users don't need to execute directly. Changed all of the executables remaining in bin to start with "trick-". In the sim_services directories changed all source files to find the Trick headers in their new location. Since all of the include files are gone in sim_services, removed the src directories as well, moving all of the source files up a level. Moved the makefiles, docs, man, and other architecture independent files into a top level share directory. Renamed lib_${TRICK_HOST_CPU} to lib64 or lib depending on the platform we're currently on.
refs #63
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/*
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PURPOSE: (Extract a bitfield. And return bitfield value.)
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REFERENCE: ((meow) (woof))
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PROGRAMMERS: (((Jane Falgout) (Lincom)) ((Alex Lin) (NASA) (8/00))) */
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#include "trick/bitfield_proto.h"
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int extract_bitfield_any(int value, /* In: Value to extract bits from */
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int size, /* In: Declared size of bitfield */
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int start, /* In: Starting bit */
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int bits)
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{ /* In: Number of bits in bitfield */
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int i = 0, j = 0;
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unsigned int mask;
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unsigned int bf;
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int sbf;
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union {
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long l;
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char c[sizeof(long)];
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} un;
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un.l = 1; /* Used for Little/Big Endian Detection */
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bf = 0x00000000;
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sbf = 0x00000000;
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if (un.c[sizeof(long) - 1] == 1) {
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/*
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* Big endian
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*/
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mask = 0x00000001 << (start + bits - 1);
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if (mask & value) {
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/*
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* This is a negative value
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*/
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for (i = start, j = 0; j < bits; i++, j++) {
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/*
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* First, turn off all bits associated with
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* this bit field within the unsigned integer.
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* Then assign the input value to the
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* appropriate bits in the unsigned integer.
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*/
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mask = 0x00000001 << i;
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if ((value & mask) != mask) {
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sbf |= mask;
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}
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}
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sbf = -((sbf >> start) + 1);
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} else {
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/*
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* This is a positive value
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*/
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for (i = start, j = 0; j < bits; i++, j++) {
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/*
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* First, turn off all bits associated with
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* this bit field within the unsigned integer.
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* Then assign the input value to the appropriate
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* bits in the unsigned integer.
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*/
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mask = 0x00000001 << i;
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if ((value & mask) == mask) {
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bf |= mask;
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}
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}
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sbf = bf >> start;
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}
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} else {
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/*
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* Little endian
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*/
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/*
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* Shift the bit field contents of the current value
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* to the lsb of the underlying int.
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*/
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if (size == sizeof(short)) {
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value = value << 16;
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} else if (size == sizeof(char)) {
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value = value << 24;
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}
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if ((start + bits) < 32) {
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bf = (value) >> (32 - start - bits);
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} else {
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bf = value;
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}
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/* Now, AND the shifted bits with a mask of the appropriate size to obtain the bitfield value. */
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bf &= (0xFFFFFFFF >> (32 - bits));
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/* If this bitfield is a signed bitfield and the sign bit is set, take the two's complement of the value. */
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mask = 0x00000001 << (bits - 1);
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if (mask & bf) {
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/* This bitfield is signed and has the sign bit set. Set sbf to the reverse bits of the bitfield contents.
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Then right shift and add 1. */
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sbf = 0x00000000;
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for (i = 0; i < bits; i++) {
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mask = 0x00000001 << i;
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if ((bf & mask) != mask) {
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sbf |= mask;
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}
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}
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sbf = -(sbf + 1);
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} else {
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sbf = bf;
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}
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}
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return (sbf);
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}
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