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objfloat.c

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    Damien George authored
    This new object representation puts floats into the object word instead
    of on the heap, at the expense of reducing their precision to 30 bits.
    It only makes sense when the word size is 32-bits.
    183edefd
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    objfloat.c 8.35 KiB
    /*
     * This file is part of the Micro Python project, http://micropython.org/
     *
     * The MIT License (MIT)
     *
     * Copyright (c) 2013, 2014 Damien P. George
     *
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to deal
     * in the Software without restriction, including without limitation the rights
     * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     * copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     * THE SOFTWARE.
     */
    
    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    #include <assert.h>
    
    #include "py/nlr.h"
    #include "py/parsenum.h"
    #include "py/runtime0.h"
    #include "py/runtime.h"
    
    #if MICROPY_PY_BUILTINS_FLOAT
    
    #include <math.h>
    #include "py/formatfloat.h"
    
    #if MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_C
    
    typedef struct _mp_obj_float_t {
        mp_obj_base_t base;
        mp_float_t value;
    } mp_obj_float_t;
    
    const mp_obj_float_t mp_const_float_e_obj = {{&mp_type_float}, M_E};
    const mp_obj_float_t mp_const_float_pi_obj = {{&mp_type_float}, M_PI};
    
    #endif
    
    STATIC void float_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
        (void)kind;
        mp_float_t o_val = mp_obj_float_get(o_in);
    #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
        char buf[16];
        const int precision = 7;
    #else
        char buf[32];
        const int precision = 16;
    #endif
        mp_format_float(o_val, buf, sizeof(buf), 'g', precision, '\0');
        mp_print_str(print, buf);
        if (strchr(buf, '.') == NULL && strchr(buf, 'e') == NULL && strchr(buf, 'n') == NULL) {
            // Python floats always have decimal point (unless inf or nan)
            mp_print_str(print, ".0");
        }
    }
    
    STATIC mp_obj_t float_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
        (void)type_in;
        mp_arg_check_num(n_args, n_kw, 0, 1, false);
    
        switch (n_args) {
            case 0:
                return mp_obj_new_float(0);
    
            case 1:
            default:
                if (MP_OBJ_IS_STR(args[0])) {
                    // a string, parse it
                    mp_uint_t l;
                    const char *s = mp_obj_str_get_data(args[0], &l);
                    return mp_parse_num_decimal(s, l, false, false, NULL);
                } else if (mp_obj_is_float(args[0])) {
                    // a float, just return it
                    return args[0];
                } else {
                    // something else, try to cast it to a float
                    return mp_obj_new_float(mp_obj_get_float(args[0]));
                }
        }
    }
    
    STATIC mp_obj_t float_unary_op(mp_uint_t op, mp_obj_t o_in) {
        mp_float_t val = mp_obj_float_get(o_in);
        switch (op) {
            case MP_UNARY_OP_BOOL: return mp_obj_new_bool(val != 0);
            case MP_UNARY_OP_POSITIVE: return o_in;
            case MP_UNARY_OP_NEGATIVE: return mp_obj_new_float(-val);
            default: return MP_OBJ_NULL; // op not supported
        }
    }
    
    STATIC mp_obj_t float_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
        mp_float_t lhs_val = mp_obj_float_get(lhs_in);
    #if MICROPY_PY_BUILTINS_COMPLEX
        if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_complex)) {
            return mp_obj_complex_binary_op(op, lhs_val, 0, rhs_in);
        } else
    #endif
        {
            return mp_obj_float_binary_op(op, lhs_val, rhs_in);
        }
    }
    
    const mp_obj_type_t mp_type_float = {
        { &mp_type_type },
        .name = MP_QSTR_float,
        .print = float_print,
        .make_new = float_make_new,
        .unary_op = float_unary_op,
        .binary_op = float_binary_op,
    };
    
    #if MICROPY_OBJ_REPR != MICROPY_OBJ_REPR_C
    
    mp_obj_t mp_obj_new_float(mp_float_t value) {
        mp_obj_float_t *o = m_new(mp_obj_float_t, 1);
        o->base.type = &mp_type_float;
        o->value = value;
        return (mp_obj_t)o;
    }
    
    mp_float_t mp_obj_float_get(mp_obj_t self_in) {
        assert(mp_obj_is_float(self_in));
        mp_obj_float_t *self = self_in;
        return self->value;
    }
    
    #endif
    
    STATIC void mp_obj_float_divmod(mp_float_t *x, mp_float_t *y) {
        // logic here follows that of CPython
        // https://docs.python.org/3/reference/expressions.html#binary-arithmetic-operations
        // x == (x//y)*y + (x%y)
        // divmod(x, y) == (x//y, x%y)
        mp_float_t mod = MICROPY_FLOAT_C_FUN(fmod)(*x, *y);
        mp_float_t div = (*x - mod) / *y;
    
        // Python specs require that mod has same sign as second operand
        if (mod == 0.0) {
            mod = MICROPY_FLOAT_C_FUN(copysign)(0.0, *y);
        } else {
            if ((mod < 0.0) != (*y < 0.0)) {
                mod += *y;
                div -= 1.0;
            }
        }
    
        mp_float_t floordiv;
        if (div == 0.0) {
            // if division is zero, take the correct sign of zero
            floordiv = MICROPY_FLOAT_C_FUN(copysign)(0.0, *x / *y);
        } else {
            // Python specs require that x == (x//y)*y + (x%y)
            floordiv = MICROPY_FLOAT_C_FUN(floor)(div);
            if (div - floordiv > 0.5) {
                floordiv += 1.0;
            }
        }
    
        // return results
        *x = floordiv;
        *y = mod;
    }
    
    mp_obj_t mp_obj_float_binary_op(mp_uint_t op, mp_float_t lhs_val, mp_obj_t rhs_in) {
        mp_float_t rhs_val = mp_obj_get_float(rhs_in); // can be any type, this function will convert to float (if possible)
        switch (op) {
            case MP_BINARY_OP_ADD:
            case MP_BINARY_OP_INPLACE_ADD: lhs_val += rhs_val; break;
            case MP_BINARY_OP_SUBTRACT:
            case MP_BINARY_OP_INPLACE_SUBTRACT: lhs_val -= rhs_val; break;
            case MP_BINARY_OP_MULTIPLY:
            case MP_BINARY_OP_INPLACE_MULTIPLY: lhs_val *= rhs_val; break;
            case MP_BINARY_OP_FLOOR_DIVIDE:
            case MP_BINARY_OP_INPLACE_FLOOR_DIVIDE:
                if (rhs_val == 0) {
                    zero_division_error:
                    nlr_raise(mp_obj_new_exception_msg(&mp_type_ZeroDivisionError, "division by zero"));
                }
                // Python specs require that x == (x//y)*y + (x%y) so we must
                // call divmod to compute the correct floor division, which
                // returns the floor divide in lhs_val.
                mp_obj_float_divmod(&lhs_val, &rhs_val);
                break;
            case MP_BINARY_OP_TRUE_DIVIDE:
            case MP_BINARY_OP_INPLACE_TRUE_DIVIDE:
                if (rhs_val == 0) {
                    goto zero_division_error;
                }
                lhs_val /= rhs_val;
                break;
            case MP_BINARY_OP_MODULO:
            case MP_BINARY_OP_INPLACE_MODULO:
                if (rhs_val == 0) {
                    goto zero_division_error;
                }
                lhs_val = MICROPY_FLOAT_C_FUN(fmod)(lhs_val, rhs_val);
                // Python specs require that mod has same sign as second operand
                if (lhs_val == 0.0) {
                    lhs_val = MICROPY_FLOAT_C_FUN(copysign)(0.0, rhs_val);
                } else {
                    if ((lhs_val < 0.0) != (rhs_val < 0.0)) {
                        lhs_val += rhs_val;
                    }
                }
                break;
            case MP_BINARY_OP_POWER:
            case MP_BINARY_OP_INPLACE_POWER: lhs_val = MICROPY_FLOAT_C_FUN(pow)(lhs_val, rhs_val); break;
            case MP_BINARY_OP_DIVMOD: {
                if (rhs_val == 0) {
                    goto zero_division_error;
                }
                mp_obj_float_divmod(&lhs_val, &rhs_val);
                mp_obj_t tuple[2] = {
                    mp_obj_new_float(lhs_val),
                    mp_obj_new_float(rhs_val),
                };
                return mp_obj_new_tuple(2, tuple);
            }
            case MP_BINARY_OP_LESS: return mp_obj_new_bool(lhs_val < rhs_val);
            case MP_BINARY_OP_MORE: return mp_obj_new_bool(lhs_val > rhs_val);
            case MP_BINARY_OP_EQUAL: return mp_obj_new_bool(lhs_val == rhs_val);
            case MP_BINARY_OP_LESS_EQUAL: return mp_obj_new_bool(lhs_val <= rhs_val);
            case MP_BINARY_OP_MORE_EQUAL: return mp_obj_new_bool(lhs_val >= rhs_val);
    
            default:
                return MP_OBJ_NULL; // op not supported
        }
        return mp_obj_new_float(lhs_val);
    }
    
    #endif // MICROPY_PY_BUILTINS_FLOAT