diff --git a/py/format-float.c b/py/format-float.c
new file mode 100644
index 0000000000000000000000000000000000000000..5411ae24f69d2df4b9f660a810dbcf0c58200c3f
--- /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 0000000000000000000000000000000000000000..590fb0e91d75db9e8646910083dac30d0682444f
--- /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 8ba9946b7ea59283db24ec6d0eae90a0d5eeaa5c..5b953f05eb12cea3257e39bd605a6e63a3954520 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) {
diff --git a/py/py.mk b/py/py.mk
index 579375e7d2dec168e2a72498f85aeb69866c3eb9..4fd295f8e50e0bf3999fe3ec697edb3c031e8d3f 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -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 3f48c43f04f169c18c037df25d39faf235018ca4..57c92181b8b1f7996e4b19389e11fffc0acda9d3 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 abbc58b669ee7864893cd7203cd76d9f44a513ce..56a5d864cfa1891e0513b6b2dc2a44ccf103b2b6 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