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Diffstat (limited to 'src/lib/util/coreutil.c')
-rw-r--r-- | src/lib/util/coreutil.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/lib/util/coreutil.c b/src/lib/util/coreutil.c new file mode 100644 index 00000000000..daaf116dc9c --- /dev/null +++ b/src/lib/util/coreutil.c @@ -0,0 +1,102 @@ +/*************************************************************************** + + coreutil.c + + Miscellaneous utility code + + Copyright (c) 1996-2007, Nicola Salmoria and the MAME Team. + Visit http://mamedev.org for licensing and usage restrictions. + +****************************************************************************/ + +#include "coreutil.h" + + +/*************************************************************************** + BINARY CODED DECIMAL HELPERS +***************************************************************************/ + +int bcd_adjust(int value) +{ + if ((value & 0xf) >= 0xa) + value = value + 0x10 - 0xa; + if ((value & 0xf0) >= 0xa0) + value = value - 0xa0 + 0x100; + return value; +} + + +UINT32 dec_2_bcd(UINT32 a) +{ + UINT32 result = 0; + int shift = 0; + + while (a != 0) + { + result |= (a % 10) << shift; + a /= 10; + shift += 4; + } + return result; +} + + +UINT32 bcd_2_dec(UINT32 a) +{ + UINT32 result = 0; + UINT32 scale = 1; + + while (a != 0) + { + result += (a & 0x0f) * scale; + a >>= 4; + scale *= 10; + } + return result; +} + + + +/*************************************************************************** + GREGORIAN CALENDAR HELPERS +***************************************************************************/ + +int gregorian_is_leap_year(int year) +{ + return !(year % 100 ? year % 4 : year % 400); +} + + +/* months are one counted */ +int gregorian_days_in_month(int month, int year) +{ + if (month == 2) + return gregorian_is_leap_year(year) ? 29 : 28; + else if (month == 4 || month == 6 || month == 9 || month == 11) + return 30; + else + return 31; +} + + +/*************************************************************************** + MISC +***************************************************************************/ + +void rand_memory(void *memory, size_t length) +{ + UINT8 *bytes = (UINT8 *) memory; + UINT32 currand; + size_t i; + + currand = rand(); + currand <<= 15; + currand ^= rand(); + + for (i = 0; i < length; i++) + { + currand = currand * 214013 + 2531011; + bytes[i] = (UINT8) (currand >> 16); + } +} + |