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/* See LICENSE file for copyright and license details. */
#include "common.h"
enum libsyscalls_error
libsyscalls_section_value(unsigned long long int value_in, size_t bits,
enum libsyscalls_datatype_section section,
unsigned long long int *value_out)
{
unsigned long long int value = value_in, mask, shift;
size_t hbits;
if (bits > sizeof(value) / sizeof(char) * CHAR_BIT ||
bits & (size_t)(LIBSYSCALLS_GET_SECTION_FRACTION(section) - 1U))
return LIBSYSCALLS_E_INVAL;
bits /= (size_t)LIBSYSCALLS_GET_SECTION_FRACTION(section);
if (bits == sizeof(mask) / sizeof(char) * CHAR_BIT)
mask = ~0ULL;
else
mask = (1ULL << bits) - 1ULL;
switch (section) {
case LIBSYSCALLS_SECTION_UNDETERMINED:
case LIBSYSCALLS_SECTION_WHOLE: /* 0xFFFFFFFFFFFFFFFF */
case LIBSYSCALLS_SECTION_LOWER_HALF: /* 0x00000000FFFFFFFF */
case LIBSYSCALLS_SECTION_LOWER_QUARTER: /* 0x000000000000FFFF */
break;
case LIBSYSCALLS_SECTION_UPPER_HALF: /* 0xFFFFFFFF00000000 */
case LIBSYSCALLS_SECTION_LOWER_MID_QUARTER: /* 0x00000000FFFF0000 */
value >>= bits;
break;
case LIBSYSCALLS_SECTION_INNER_HALF: /* 0x0000FFFFFFFF0000 */
value >>= bits / 2;
break;
case LIBSYSCALLS_SECTION_UPPER_MID_QUARTER: /* 0x0000FFFF00000000 */
value >>= bits * 2;
break;
case LIBSYSCALLS_SECTION_UPPER_QUARTER: /* 0xFFFF000000000000 */
value >>= bits * 3;
break;
case LIBSYSCALLS_SECTION_OUTER_HALF: /* 0xFFFF00000000FFFF */
hbits = bits / 2;
value = ((value & (mask << (bits + hbits))) >> bits)
| (value & (mask >> hbits));
break;
case LIBSYSCALLS_SECTION_ODD_QUARTERS_AS_HALF: /* 0xFFFF0000FFFF0000 */
value >>= bits / 2;
/* fall through */
case LIBSYSCALLS_SECTION_EVEN_QUARTERS_AS_HALF: /* 0x0000FFFF0000FFFF */
hbits = bits / 2;
value = ((value & (mask << hbits) & ~mask) >> hbits)
| (value & (mask >> hbits));
break;
case LIBSYSCALLS_SECTION_ODD_BYTES_AS_HALF: /* 0xFF00FF00FF00FF00 */
value_in >>= 8;
/* fall through */
case LIBSYSCALLS_SECTION_EVEN_BYTES_AS_HALF: /* 0x00FF00FF00FF00FF */
value = 0;
for (shift = 0; value_in; value_in >>= 16, shift += 8)
value |= (value_in & 0x00FFU) << shift;
break;
default:
return LIBSYSCALLS_E_INVAL;
}
value &= mask;
masked:
if (value_out)
*value_out = value;
return LIBSYSCALLS_E_OK;
}
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