diff options
| -rw-r--r-- | py/format-float.c | 311 | ||||
| -rw-r--r-- | py/format-float.h | 3 | ||||
| -rw-r--r-- | py/objfloat.c | 9 | ||||
| -rw-r--r-- | py/py.mk | 1 | ||||
| -rw-r--r-- | stm/mpconfigport.h | 1 | ||||
| -rw-r--r-- | stm/printf.c | 54 |
6 files changed, 359 insertions, 20 deletions
diff --git a/py/format-float.c b/py/format-float.c new file mode 100644 index 0000000000..5411ae24f6 --- /dev/null +++ b/py/format-float.c @@ -0,0 +1,311 @@ +/*********************************************************************** + + format-float.c - Ruutine for converting a single-precision floating + point number into a string. + + The code in this funcion was inspired from Fred Bayer's pdouble.c. + Since pdouble.c was released as Public Domain, I'm releasing this + code as public domain as well. + + The original code can be found in https://github.com/dhylands/format-float + + Dave Hylands + +***********************************************************************/ + +#include <stdint.h> +#include <stdlib.h> + +#include "mpconfig.h" + +#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT +#include "format-float.h" + +// 1 sign bit, 8 exponent bits, and 23 mantissa bits. +// exponent values 0 and 255 are reserved, exponent can be 1 to 254. +// exponent is stored with a bias of 127. +// The min and max floats are on the order of 1x10^37 and 1x10^-37 + +#define FLT_SIGN_MASK 0x80000000 +#define FLT_EXP_MASK 0x7F800000 +#define FLT_MAN_MASK 0x007FFFFF + +static const float g_pos_pow[] = { + 1e32, 1e16, 1e8, 1e4, 1e2, 1e1 +}; +static const float g_neg_pow[] = { + 1e-32, 1e-16, 1e-8, 1e-4, 1e-2, 1e-1 +}; + +int format_float(float f, char *buf, size_t buf_size, char fmt, int prec, char sign) { + + char *s = buf; + int buf_remaining = buf_size - 1; + + union { + float f; + uint32_t u; + } num = {f}; + + if (buf_size < 7) { + // Smallest exp notion is -9e+99 which is 6 chars plus terminating + // nulll. + + if (buf_size >= 2) { + *s++ = '?'; + } + if (buf_size >= 1) { + *s++ = '\0'; + } + return buf_size >= 2; + } + if (num.u & FLT_SIGN_MASK) { + *s++ = '-'; + num.u &= ~FLT_SIGN_MASK; + } else { + if (sign) { + *s++ = sign; + } + } + buf_remaining -= (s - buf); // Adjust for sign + + if ((num.u & FLT_EXP_MASK) == FLT_EXP_MASK) { + char uc = fmt & 0x20; + if ((num.u & FLT_MAN_MASK) == 0) { + *s++ = 'I' ^ uc; + *s++ = 'N' ^ uc; + *s++ = 'F' ^ uc; + } else { + *s++ = 'N' ^ uc; + *s++ = 'A' ^ uc; + *s++ = 'N' ^ uc; + } + *s = '\0'; + return s - buf; + } + + if (prec < 0) { + prec = 6; + } + char e_char = 'E' | (fmt & 0x20); // e_char will match case of fmt + fmt |= 0x20; // Force fmt to be lowercase + char org_fmt = fmt; + if (fmt == 'g' && prec == 0) { + prec = 1; + } + int e, e1; + int dec = 0; + char e_sign = '\0'; + int num_digits = 0; + const float *pos_pow = g_pos_pow; + const float *neg_pow = g_neg_pow; + + if (num.u == 0) { + e = 0; + if (fmt == 'e') { + e_sign = '+'; + } else if (fmt == 'f') { + num_digits = prec + 1; + } + } else if (num.u < 0x3f800000) { // f < 1.0 + // Build negative exponent + for (e = 0, e1 = 32; e1; e1 >>= 1, pos_pow++, neg_pow++) { + if (*neg_pow > num.f) { + e += e1; + num.f *= *pos_pow; + } + } + if (num.f < 1.0F && num.f >= 0.9999995F) { + num.f = 1.0F; + } else { + e++; + num.f *= 10.0F; + } + + // If the user specified 'g' format, and e is <= 4, then we'll switch + // to the fixed format ('f') + + if (fmt == 'f' || (fmt == 'g' && e <= 4)) { + fmt = 'f'; + dec = -1; + *s++ = '0'; + + if (prec + e + 1 > buf_remaining) { + prec = buf_remaining - e - 1; + } + + if (org_fmt == 'g') { + prec += (e - 1); + } + num_digits = prec; + if (num_digits) { + *s++ = '.'; + while (--e && num_digits) { + *s++ = '0'; + num_digits--; + } + } + } else { + // For e & g formats, we'll be printing the exponent, so set the + // sign. + e_sign = '-'; + dec = 0; + + if (prec > (buf_remaining - 6)) { + prec = buf_remaining - 6; + if (fmt == 'g') { + prec++; + } + } + } + } else { + // Build positive exponent + for (e = 0, e1 = 32; e1; e1 >>= 1, pos_pow++, neg_pow++) { + if (*pos_pow <= num.f) { + e += e1; + num.f *= *neg_pow; + } + } + + // If the user specified fixed format (fmt == 'f') and e makes the + // number too big to fit into the available buffer, then we'll + // switch to the 'e' format. + + if (fmt == 'f') { + if (e >= buf_remaining) { + fmt = 'e'; + } else if ((e + prec + 2) > buf_remaining) { + prec = buf_remaining - e - 2; + if (prec < 0) { + // This means no decimal point, so we can add one back + // for the decimal. + prec++; + } + } + } + if (fmt == 'e' && prec > (buf_remaining - 6)) { + prec = buf_remaining - 6; + } + // If the user specified 'g' format, and e is < prec, then we'll switch + // to the fixed format. + + if (fmt == 'g' && e < prec) { + fmt = 'f'; + prec -= (e + 1); + } + if (fmt == 'f') { + dec = e; + num_digits = prec + e + 1; + } else { + e_sign = '+'; + } + } + if (prec < 0) { + // This can happen when the prec is trimmed to prevent buffer overflow + prec = 0; + } + + // We now have num.f as a floating point number between >= 1 and < 10 + // (or equal to zero), and e contains the absolute value of the power of + // 10 exponent. and (dec + 1) == the number of dgits before the decimal. + + // For e, prec is # digits after the decimal + // For f, prec is # digits after the decimal + // For g, prec is the max number of significant digits + // + // For e & g there will be a single digit before the decimal + // for f there will be e digits before the decimal + + if (fmt == 'e') { + num_digits = prec + 1; + } else if (fmt == 'g') { + if (prec == 0) { + prec = 1; + } + num_digits = prec; + } + + // Print the digits of the mantissa + for (int i = 0; i < num_digits; ++i, --dec) { + int32_t d = num.f; + *s++ = '0' + d; + if (dec == 0 && prec > 0) { + *s++ = '.'; + } + num.f -= (float)d; + num.f *= 10.0F; + } + + // Round + if (num.f >= 5.0F) { + char *rs = s; + rs--; + while (1) { + if (*rs == '.') { + rs--; + continue; + } + if (*rs < '0' || *rs > '9') { + // + or - + rs++; // So we sit on the digit to the right of the sign + break; + } + if (*rs < '9') { + (*rs)++; + break; + } + *rs = '0'; + if (rs == buf) { + break; + } + rs--; + } + if (*rs == '0') { + // We need to insert a 1 + if (rs[1] == '.' && fmt != 'f') { + // We're going to round 9.99 to 10.00 + // Move the decimal point + rs[0] = '.'; + rs[1] = '0'; + if (e_sign == '-') { + e--; + } else { + e++; + } + } + s++; + char *ss = s; + while (ss > rs) { + *ss = ss[-1]; + ss--; + } + *rs = '1'; + } + if (num.u < 0x3f800000 && fmt == 'f') { + // We rounded up to 1.0 + prec--; + } + } + + if (org_fmt == 'g' && prec > 0) { + // Remove trailing zeros and a trailing decimal point + while (s[-1] == '0') { + s--; + } + if (s[-1] == '.') { + s--; + } + } + // Append the exponent + if (e_sign) { + *s++ = e_char; + *s++ = e_sign; + *s++ = '0' + (e / 10); + *s++ = '0' + (e % 10); + } + *s = '\0'; + + return s - buf; +} + +#endif diff --git a/py/format-float.h b/py/format-float.h new file mode 100644 index 0000000000..590fb0e91d --- /dev/null +++ b/py/format-float.h @@ -0,0 +1,3 @@ +int format_float(float f, char *buf, size_t bufSize, char fmt, int prec, char sign); + + diff --git a/py/objfloat.c b/py/objfloat.c index 8ba9946b7e..5b953f05eb 100644 --- a/py/objfloat.c +++ b/py/objfloat.c @@ -12,12 +12,21 @@ #include "runtime0.h" #if MICROPY_ENABLE_FLOAT +#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT +#include "format-float.h" +#endif mp_obj_t mp_obj_new_float(mp_float_t value); STATIC void float_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) { mp_obj_float_t *o = o_in; +#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT + char buf[32]; + format_float(o->value, buf, sizeof(buf), 'g', 6, '\0'); + print(env, "%s", buf); +#else print(env, "%.8g", (double) o->value); +#endif } STATIC mp_obj_t float_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) { @@ -32,6 +32,7 @@ PY_O_BASENAME = \ asmthumb.o \ emitnthumb.o \ emitinlinethumb.o \ + format-float.o \ parsenumbase.o \ parsenum.o \ runtime.o \ diff --git a/stm/mpconfigport.h b/stm/mpconfigport.h index 3f48c43f04..57c92181b8 100644 --- a/stm/mpconfigport.h +++ b/stm/mpconfigport.h @@ -7,6 +7,7 @@ #define MICROPY_ENABLE_GC (1) #define MICROPY_ENABLE_REPL_HELPERS (1) #define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_MPZ) +#define MICROPY_ENABLE_FLOAT (1) #define MICROPY_FLOAT_IMPL (MICROPY_FLOAT_IMPL_FLOAT) #define MICROPY_PATH_MAX (128) /* Enable FatFS LFNs diff --git a/stm/printf.c b/stm/printf.c index abbc58b669..56a5d864cf 100644 --- a/stm/printf.c +++ b/stm/printf.c @@ -11,6 +11,9 @@ #include "lcd.h" #include "usart.h" #include "usb.h" +#if MICROPY_ENABLE_FLOAT +#include "format-float.h" +#endif #define PF_FLAG_LEFT_ADJUST (0x01) #define PF_FLAG_SHOW_SIGN (0x02) @@ -210,29 +213,40 @@ int pfenv_printf(const pfenv_t *pfenv, const char *fmt, va_list args) { chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 16, 'A', flags, width); break; #if MICROPY_ENABLE_FLOAT + case 'e': + case 'E': + case 'f': + case 'F': case 'g': + case 'G': { - // This is a very hacky approach to printing floats. Micropython - // uses %g when using print, and I just wanted to see somthing - // usable. I expect that this will be replaced with something - // more appropriate. - char dot = '.'; - mp_float_t d = va_arg(args, double); - int left = (int)d; - int right = (int)((d - (mp_float_t)(int)d) * 1000000.0); - if (right < 0) { - if (left == 0) { - chrs += pfenv_print_strn(pfenv, "-0", 2, flags, width); - } else { - chrs += pfenv_print_int(pfenv, left, 1, 10, 'a', flags, width); - } - chrs += pfenv_print_strn(pfenv, &dot, 1, flags, width); - chrs += pfenv_print_int(pfenv, -right, 0, 10, 'a', PF_FLAG_ZERO_PAD, 6); - } else { - chrs += pfenv_print_int(pfenv, left, 1, 10, 'a', flags, width); - chrs += pfenv_print_strn(pfenv, &dot, 1, flags, width); - chrs += pfenv_print_int(pfenv, right, 0, 10, 'a', PF_FLAG_ZERO_PAD, 6); + char buf[32]; + char sign = '\0'; + + if (flags & PF_FLAG_SHOW_SIGN) { + sign = '+'; + } + else + if (flags & PF_FLAG_SPACE_SIGN) { + sign = ' '; + } + float f = va_arg(args, double); + int len = format_float(f, buf, sizeof(buf), *fmt, prec, sign); + char *s = buf; + + // buf[0] < '0' returns true if the first character is space, + or - + // buf[1] < '9' matches a digit, and doesn't match when we get back +nan or +inf + if (buf[0] < '0' && buf[1] <= '9' && (flags & PF_FLAG_ZERO_PAD)) { + chrs += pfenv_print_strn(pfenv, &buf[0], 1, 0, 1); + s++; + width--; + len--; + } + if (*s < '0' || *s >= '9') { + // For inf or nan, we don't want to zero pad. + flags &= ~PF_FLAG_ZERO_PAD; } + chrs += pfenv_print_strn(pfenv, s, len, flags, width); break; } #endif |