restructuring

F3:F303/floatPrintf/main.c

@@ -0,0 +1,131 @@
+/*
+ * This file is part of the F303usart project.
+ * Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "stm32f3.h"
+#include "hardware.h"
+#include "usart.h"
+
+volatile uint32_t Tms = 0;
+
+void sys_tick_handler(void){
+    ++Tms;
+}
+
+// be careful: if pow10 would be bigger you should change str[] size!
+static const float pwr10[] = {1., 10., 100., 1000., 10000.};
+static const float rounds[] = {0.5, 0.05, 0.005, 0.0005, 0.00005};
+#define P10L  (sizeof(pwr10)/sizeof(uint32_t) - 1)
+static char * float2str(float x, uint8_t prec){
+    if(prec > P10L) prec = P10L;
+    static char str[16] = {0}; // -117.5494E-36\0 - 14 symbols max!
+    char *s = str + 14; // go to end of buffer
+    uint8_t minus = 0;
+    if(x < 0){
+        x = -x;
+        minus = 1;
+    }
+    int pow = 0; // xxxEpow
+    // now convert float to 1.xxxE3y
+    while(x > 1000.f){
+        x /= 1000.f;
+        pow += 3;
+    }
+    if(x > 0.) while(x < 1.){
+        x *= 1000.f;
+        pow -= 3;
+    }
+    // print Eyy
+    if(pow){
+        uint8_t m = 0;
+        if(pow < 0){pow = -pow; m = 1;}
+        while(pow){
+            register int p10 = pow/10;
+            *s-- = '0' + (pow - 10*p10);
+            pow = p10;
+        }
+        if(m) *s-- = '-';
+        *s-- = 'E';
+    }
+    // now our number is in [1, 1000]
+    uint32_t units;
+    if(prec){
+        units = (uint32_t) x;
+        uint32_t decimals = (uint32_t)((x-units+rounds[prec])*pwr10[prec]);
+        // print decimals
+        while(prec){
+            register int d10 = decimals / 10;
+            *s-- = '0' + (decimals - 10*d10);
+            decimals = d10;
+            --prec;
+        }
+        // decimal point
+        *s-- = '.';
+    }else{ // without decimal part
+        units = (uint32_t) (x + 0.5);
+    }
+    // print main units
+    if(units == 0) *s-- = '0';
+    else while(units){
+        register uint32_t u10 = units / 10;
+        *s-- = '0' + (units - 10*u10);
+        units = u10;
+    }
+    if(minus) *s-- = '-';
+    return s+1;
+}
+
+static const float tests[] = {-1.23456789e-37, -3.14159265e-2, -1234.56789, -1.2345678, 0., 1e-40, 0.1234567, 123.456789, 2.473829e31};
+#define TESTN 9
+
+int main(void){
+    sysreset();
+    if(!StartHSE()) StartHSI();
+    SysTick_Config((uint32_t)72000); // 1ms
+    hw_setup();
+    usart_setup();
+    usart_send("Start\n");
+    uint32_t ctr = Tms;
+    float x = 0.519, more = 5.123;
+    while(1){
+        if(Tms - ctr > 499){
+            ctr = Tms;
+            pin_toggle(GPIOB, 1 << 1 | 1 << 0); // toggle LED @ PB0
+            /**/
+            if((x += 0.519) > more){
+                more += 5.123;
+            }
+        }
+        if(bufovr){
+            bufovr = 0;
+            usart_send("bufovr\n");
+        }
+        char *txt = NULL;
+        if(usart_getline(&txt)){
+            if(*txt == '?'){
+                for(int i = 0; i < TESTN; ++i) for(int j = 0; j <= (int)P10L; ++j){
+                    usart_send(float2str(tests[i], j));
+                    usart_putchar('\n');
+                }
+            }else{
+                usart_send("Get by USART1: ");
+                usart_send(txt);
+                usart_putchar('\n');
+            }
+        }
+    }
+}