mirrors
/
Tasmota
mirror of https://github.com/arendst/Tasmota.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add more accurate fmodf function and make available to all core versions lowering code footprint 

Add more accurate fmodf function and make available to all core versions lowering code footprint
This commit is contained in:
Theo Arends 2019-07-03 12:32:44 +02:00
parent 2f701da069
commit db05d920cf
1 changed files with 50 additions and 70 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

120
sonoff/support_float.ino
View File

@ -17,93 +17,73 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef ARDUINO_ESP8266_RELEASE_2_3_0
//#ifdef ARDUINO_ESP8266_RELEASE_2_3_0
// Functions not available in 2.3.0
// https://code.woboq.org/userspace/glibc/sysdeps/ieee754/flt-32/e_fmodf.c.html
float fmodf(float x, float y)
{
const float Zero[] = { 0.0, -0.0 };
// https://github.com/micropython/micropython/blob/master/lib/libm/fmodf.c
union {float f; uint32_t i;} ux = {x}, uy = {y};
int ex = ux.i>>23 & 0xff;
int ey = uy.i>>23 & 0xff;
uint32_t sx = ux.i & 0x80000000;
uint32_t i;
uint32_t uxi = ux.i;
int32_t hx = (int32_t)x;
int32_t hy = (int32_t)y;
int32_t sx = hx &0x80000000; // sign of x
hx ^= sx; // |x|
hy &= 0x7fffffff; // |y|
// purge off exception values
if ((0 == hy) || (hx >= 0x7f800000) || (hy > 0x7f800000)) { // y=0, or x not finite, or y is NaN
return (x * y) / (x * y);
if (uy.i<<1 == 0 || isnan(y) || ex == 0xff)
return (x*y)/(x*y);
if (uxi<<1 <= uy.i<<1) {
if (uxi<<1 == uy.i<<1)
return 0*x;
return x;
}
if (hx < hy) { return x; } // |x|<|y| return x
if (hx == hy) { return Zero[(uint32_t)sx >> 31]; } // |x|=|y| return x*0
int32_t n, hz, ix, iy, i;
// determine ix = ilogb(x)
if (hx < 0x00800000) { // subnormal x
for (ix = -126, i = (hx << 8); i > 0; i <<= 1) { ix -=1; }
// normalize x and y
if (!ex) {
for (i = uxi<<9; i>>31 == 0; ex--, i <<= 1);
uxi <<= -ex + 1;
} else {
ix = (hx >> 23) -127;
uxi &= -1U >> 9;
uxi |= 1U << 23;
}
// determine iy = ilogb(y)
if (hy < 0x00800000) { // subnormal y
for (iy = -126, i = (hy << 8); i >= 0; i <<= 1) { iy -=1; }
if (!ey) {
for (i = uy.i<<9; i>>31 == 0; ey--, i <<= 1);
uy.i <<= -ey + 1;
} else {
iy = (hy >> 23) -127;
uy.i &= -1U >> 9;
uy.i |= 1U << 23;
}
// set up {hx,lx}, {hy,ly} and align y to x
if (ix >= -126) {
hx = 0x00800000 | (0x007fffff & hx);
} else { // subnormal x, shift x to normal
n = -126 - ix;
hx = hx << n;
}
if (iy >= -126) {
hy = 0x00800000 | (0x007fffff & hy);
} else { // subnormal y, shift y to normal
n = -126 - iy;
hy = hy << n;
}
// fix point fmod
n = ix - iy;
while (n--) {
hz = hx - hy;
if (hz < 0) {
hx = hx + hx;
} else {
if (hz == 0) { // return sign(x)*0
return Zero[(uint32_t)sx >> 31];
}
hx = hz + hz;
// x mod y
for (; ex > ey; ex--) {
i = uxi - uy.i;
if (i >> 31 == 0) {
if (i == 0)
return 0*x;
uxi = i;
}
uxi <<= 1;
}
hz = hx - hy;
if (hz >= 0) { hx = hz; }
i = uxi - uy.i;
if (i >> 31 == 0) {
if (i == 0)
return 0*x;
uxi = i;
}
for (; uxi>>23 == 0; uxi <<= 1, ex--);
// convert back to floating value and restore the sign
if (0 == hx) { // return sign(x)*0
return Zero[(uint32_t)sx >> 31];
// scale result up
if (ex > 0) {
uxi -= 1U << 23;
uxi |= (uint32_t)ex << 23;
} else {
uxi >>= -ex + 1;
}
while (hx < 0x00800000) { // normalize x
hx = hx + hx;
iy -= 1;
}
if (iy >= -126) { // normalize output
hx = ((hx - 0x00800000) | ((iy +127) << 23));
x = (float)(hx | sx);
} else { // subnormal output
n = -126 - iy;
hx >>= n;
x = (float)(hx | sx);
x *= 1.0; // create necessary signal
}
return x; // exact output
uxi |= sx;
ux.i = uxi;
return ux.f;
}
#endif // ARDUINO_ESP8266_RELEASE_2_3_0
//#endif // ARDUINO_ESP8266_RELEASE_2_3_0
double FastPrecisePow(double a, double b)
{