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-rw-r--r--py/formatfloat.c183
1 files changed, 75 insertions, 108 deletions
diff --git a/py/formatfloat.c b/py/formatfloat.c
index a801055a65..ac5a74e8fc 100644
--- a/py/formatfloat.c
+++ b/py/formatfloat.c
@@ -24,14 +24,16 @@
* THE SOFTWARE.
*/
+#include "py/mpconfig.h"
+#if MICROPY_FLOAT_IMPL != MICROPY_FLOAT_IMPL_NONE
+
#include <stdlib.h>
#include <stdint.h>
#include "py/formatfloat.h"
-#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
/***********************************************************************
- Routine for converting a single-precision floating
+ Routine for converting a arbitrary floating
point number into a string.
The code in this funcion was inspired from Fred Bayer's pdouble.c.
@@ -44,32 +46,67 @@
***********************************************************************/
+#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
// 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 FPTYPE float
+#define FPCONST(x) x##F
+#define FPROUND_TO_ONE 0.9999995F
+#define FPDECEXP 32
+
#define FLT_SIGN_MASK 0x80000000
#define FLT_EXP_MASK 0x7F800000
#define FLT_MAN_MASK 0x007FFFFF
-static const float g_pos_pow[] = {
+union floatbits {
+ float f;
+ uint32_t u;
+};
+static inline int fp_signbit(float x) { union floatbits fb = {x}; return fb.u & FLT_SIGN_MASK; }
+static inline int fp_isspecial(float x) { union floatbits fb = {x}; return (fb.u & FLT_EXP_MASK) == FLT_EXP_MASK; }
+static inline int fp_isinf(float x) { union floatbits fb = {x}; return (fb.u & FLT_MAN_MASK) == 0; }
+static inline int fp_iszero(float x) { union floatbits fb = {x}; return fb.u == 0; }
+static inline int fp_isless1(float x) { union floatbits fb = {x}; return fb.u < 0x3f800000; }
+// Assumes both fp_isspecial() and fp_isinf() were applied before
+#define fp_isnan(x) 1
+
+#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
+
+#define FPTYPE double
+#define FPCONST(x) x
+#define FPROUND_TO_ONE 0.999999999995
+#define FPDECEXP 256
+#include <math.h>
+#define fp_signbit(x) signbit(x)
+#define fp_isspecial(x) 1
+#define fp_isnan(x) isnan(x)
+#define fp_isinf(x) isinf(x)
+#define fp_iszero(x) (x == 0)
+#define fp_isless1(x) (x < 1.0)
+
+#endif
+
+static const FPTYPE g_pos_pow[] = {
+ #if FPDECEXP > 32
+ 1e256, 1e128, 1e64,
+ #endif
1e32, 1e16, 1e8, 1e4, 1e2, 1e1
};
-static const float g_neg_pow[] = {
+static const FPTYPE g_neg_pow[] = {
+ #if FPDECEXP > 32
+ 1e-256, 1e-128, 1e-64,
+ #endif
1e-32, 1e-16, 1e-8, 1e-4, 1e-2, 1e-1
};
-int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, char sign) {
+int mp_format_float(FPTYPE 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
// null.
@@ -82,9 +119,9 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
}
return buf_size >= 2;
}
- if (num.u & FLT_SIGN_MASK) {
+ if (fp_signbit(f)) {
*s++ = '-';
- num.u &= ~FLT_SIGN_MASK;
+ f = -f;
} else {
if (sign) {
*s++ = sign;
@@ -92,19 +129,21 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
}
buf_remaining -= (s - buf); // Adjust for sign
- if ((num.u & FLT_EXP_MASK) == FLT_EXP_MASK) {
+ if (fp_isspecial(f)) {
char uc = fmt & 0x20;
- if ((num.u & FLT_MAN_MASK) == 0) {
+ if (fp_isinf(f)) {
*s++ = 'I' ^ uc;
*s++ = 'N' ^ uc;
*s++ = 'F' ^ uc;
- } else {
+ goto ret;
+ } else if (fp_isnan(f)) {
*s++ = 'N' ^ uc;
*s++ = 'A' ^ uc;
*s++ = 'N' ^ uc;
+ ret:
+ *s = '\0';
+ return s - buf;
}
- *s = '\0';
- return s - buf;
}
if (prec < 0) {
@@ -120,28 +159,28 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
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;
+ const FPTYPE *pos_pow = g_pos_pow;
+ const FPTYPE *neg_pow = g_neg_pow;
- if (num.u == 0) {
+ if (fp_iszero(f)) {
e = 0;
if (fmt == 'e') {
e_sign = '+';
} else if (fmt == 'f') {
num_digits = prec + 1;
}
- } else if (num.u < 0x3f800000) { // f < 1.0
+ } else if (fp_isless1(f)) {
// Build negative exponent
- for (e = 0, e1 = 32; e1; e1 >>= 1, pos_pow++, neg_pow++) {
- if (*neg_pow > num.f) {
+ for (e = 0, e1 = FPDECEXP; e1; e1 >>= 1, pos_pow++, neg_pow++) {
+ if (*neg_pow > f) {
e += e1;
- num.f *= *pos_pow;
+ f *= *pos_pow;
}
}
char first_dig = '0';
char e_sign_char = '-';
- if (num.f < 1.0F && num.f >= 0.9999995F) {
- num.f = 1.0F;
+ if (fp_isless1(f) && f >= FPROUND_TO_ONE) {
+ f = FPCONST(1.0);
if (e > 1) {
// numbers less than 1.0 start with 0.xxx
first_dig = '1';
@@ -151,7 +190,7 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
}
} else {
e++;
- num.f *= 10.0F;
+ f *= FPCONST(10.0);
}
// If the user specified 'g' format, and e is <= 4, then we'll switch
@@ -192,10 +231,10 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
}
} else {
// Build positive exponent
- for (e = 0, e1 = 32; e1; e1 >>= 1, pos_pow++, neg_pow++) {
- if (*pos_pow <= num.f) {
+ for (e = 0, e1 = FPDECEXP; e1; e1 >>= 1, pos_pow++, neg_pow++) {
+ if (*pos_pow <= f) {
e += e1;
- num.f *= *neg_pow;
+ f *= *neg_pow;
}
}
@@ -259,17 +298,17 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
// Print the digits of the mantissa
for (int i = 0; i < num_digits; ++i, --dec) {
- int32_t d = num.f;
+ int32_t d = f;
*s++ = '0' + d;
if (dec == 0 && prec > 0) {
*s++ = '.';
}
- num.f -= (float)d;
- num.f *= 10.0F;
+ f -= (FPTYPE)d;
+ f *= FPCONST(10.0);
}
// Round
- if (num.f >= 5.0F) {
+ if (f >= FPCONST(5.0)) {
char *rs = s;
rs--;
while (1) {
@@ -313,7 +352,7 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
}
*rs = '1';
}
- if (num.u < 0x3f800000 && fmt == 'f') {
+ if (fp_isless1(f) && fmt == 'f') {
// We rounded up to 1.0
prec--;
}
@@ -340,76 +379,4 @@ int mp_format_float(float f, char *buf, size_t buf_size, char fmt, int prec, cha
return s - buf;
}
-#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
-
-#include <errno.h>
-#include <stdio.h>
-
-#ifdef _MSC_VER
-// For msvc we need to address some quirks in the snprintf implementation:
-// - there is no standard snprintf, it is named _snprintf instead
-// - 'F' format isn't handled so use 'f'
-// - nan and inf are printed as 1.#QNAN and 1.#INF
-#include <math.h>
-#include <string.h>
-
-STATIC int copy_with_sign(char *dest, size_t bufSize, const char *value, char sign) {
- if (bufSize == 0) {
- return 0;
- }
- size_t numSignChars = 0;
- if (sign) {
- *dest = sign;
- ++numSignChars;
- }
- // check total length including terminator
- size_t length = strlen(value) + 1 + numSignChars;
- if (length > bufSize) {
- length = bufSize;
- }
- // length without terminator
- --length;
- if (length > numSignChars) {
- memcpy(dest + numSignChars, value, length - numSignChars);
- }
- dest[length] = 0;
- return length;
-}
-
-#define snprintf _snprintf
-#endif
-
-int mp_format_float(double value, char *buf, size_t bufSize, char fmt, int prec, char sign) {
- if (!buf) {
- errno = EINVAL;
- return -1;
- }
-#ifdef _MSC_VER
- if (isnan(value)) {
- return copy_with_sign(buf, bufSize, "nan", sign);
- } else if (isinf(value)) {
- return copy_with_sign(buf, bufSize, "inf", value > 0.0 ? sign : '-');
- } else {
- if (fmt == 'F') {
- fmt = 'f';
- }
-#endif
- char fmt_buf[6];
- char *fmt_s = fmt_buf;
-
- *fmt_s++ = '%';
- if (sign) {
- *fmt_s++ = sign;
- }
- *fmt_s++ = '.';
- *fmt_s++ = '*';
- *fmt_s++ = fmt;
- *fmt_s = '\0';
-
- return snprintf(buf, bufSize, fmt_buf, prec, value);
-#ifdef _MSC_VER
- }
-#endif
-}
-
-#endif
+#endif // MICROPY_FLOAT_IMPL != MICROPY_FLOAT_IMPL_NONE
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