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py: Add float-to-int classification function

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David Steinberg 2015-01-13 15:21:17 +00:00 committed by Damien George
parent 8d427b7ab7
commit ca377b10de
2 changed files with 56 additions and 0 deletions
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46
py/objint.c
View File

@ -78,6 +78,52 @@ STATIC mp_obj_t mp_obj_int_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_
}
}
#if MICROPY_PY_BUILTINS_FLOAT
mp_fp_as_int_class_t mp_classify_fp_as_int(mp_float_t val) {
union {
mp_float_t f;
#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
uint32_t i;
#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
uint32_t i[2];
#endif
} u = {val};
uint32_t e;
#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
e = u.i;
#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
e = u.i[MP_ENDIANNESS_LITTLE];
#endif
#define MP_FLOAT_SIGN_SHIFT_I32 ((MP_FLOAT_FRAC_BITS + MP_FLOAT_EXP_BITS) % 32)
#define MP_FLOAT_EXP_SHIFT_I32 (MP_FLOAT_FRAC_BITS % 32)
if (e & (1 << MP_FLOAT_SIGN_SHIFT_I32)) {
#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
e |= u.i[MP_ENDIANNESS_BIG] != 0;
#endif
e += ((1 << MP_FLOAT_EXP_BITS) - 1) << MP_FLOAT_EXP_SHIFT_I32;
} else {
e &= ~((1 << MP_FLOAT_EXP_SHIFT_I32) - 1);
}
if (e <= ((BITS_PER_WORD + MP_FLOAT_EXP_BIAS - 3) << MP_FLOAT_EXP_SHIFT_I32)) {
return MP_FP_CLASS_FIT_SMALLINT;
}
#if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
if (e <= (((sizeof(long long) * BITS_PER_BYTE) + MP_FLOAT_EXP_BIAS - 2) << MP_FLOAT_EXP_SHIFT_I32)) {
return MP_FP_CLASS_FIT_LONGINT;
}
#endif
#if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_MPZ
return MP_FP_CLASS_FIT_LONGINT;
#else
return MP_FP_CLASS_OVERFLOW;
#endif
}
#undef MP_FLOAT_SIGN_SHIFT_I32
#undef MP_FLOAT_EXP_SHIFT_I32
#endif
void mp_obj_int_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
(void)kind;
// The size of this buffer is rather arbitrary. If it's not large

10
py/objint.h
View File

@ -40,6 +40,16 @@ typedef struct _mp_obj_int_t {
extern const mp_obj_int_t mp_maxsize_obj;
#if MICROPY_PY_BUILTINS_FLOAT
typedef enum {
MP_FP_CLASS_FIT_SMALLINT,
MP_FP_CLASS_FIT_LONGINT,
MP_FP_CLASS_OVERFLOW
} mp_fp_as_int_class_t;
mp_fp_as_int_class_t mp_classify_fp_as_int(mp_float_t val);
#endif // MICROPY_PY_BUILTINS_FLOAT
void mp_obj_int_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind);
char *mp_obj_int_formatted(char **buf, mp_uint_t *buf_size, mp_uint_t *fmt_size, mp_const_obj_t self_in,
int base, const char *prefix, char base_char, char comma);