diff options
Diffstat (limited to 'internal.h')
| -rw-r--r-- | internal.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/internal.h b/internal.h index edf7f4f6c4..76746cc3b7 100644 --- a/internal.h +++ b/internal.h @@ -266,6 +266,47 @@ nlz_int128(uint128_t x) } #endif +/* + * This behaves different from C99 for negative arguments. + * Note that div may overflow fixnum. + */ +static inline void +rb_divmod(long x, long y, long *divp, long *modp) { + /* assume / and % comply C99. + * ldiv(3) won't be inlined by GCC and clang. + * I expect / and % are compiled as single idiv. + */ + long div = x / y; + long mod = x % y; + if (y > 0 ? mod < 0 : mod > 0) { + mod += y; + div -= 1; + } + if (divp) *divp = div; + if (modp) *modp = mod; +} + +/* div() for Ruby + * This behaves different from C99 for negative arguments. + * Note that div may overflow fixnum + */ +static inline long +rb_div(long x, long y) { + long div; + rb_divmod(x, y, &div, NULL); + return div; +} + +/* mod() for Ruby + * This behaves different from C99 for negative arguments. + */ +static inline long +rb_mod(long x, long y) { + long mod; + rb_divmod(x, y, NULL, &mod); + return mod; +} + #if defined(HAVE_UINT128_T) # define bit_length(x) \ (sizeof(x) <= SIZEOF_INT ? SIZEOF_INT * CHAR_BIT - nlz_int((unsigned int)(x)) : \ |