fix exponent display

README.md

@@ -120,9 +120,8 @@ The keys on the original calculator map as follows:
 - `mode`: reserved for a future shift key
 
 # Bugs
-1. Currently, when displaying numbers, the exponent may be cut off if the number is too long.
-1. Initially, the exponent for the 1st number entered after poweron is random.
 1. Currently, trying to display numbers between `[0.1, 1)` causes the calculator to crash.
+1. There are other calculations which can randomly cause the calculator to crash.
 1. There are probably more bugs waiting to be discovered.
 
 # Internals

src/decn/decn.c

@@ -768,7 +768,7 @@ void div_decn(dec80* acc, const dec80* x){
 }
 
 //buf should hold at least 18 + 4 + 5 + 1 = 28
-void dec80_to_str(char* buf, const dec80* x){
+int8_t decn_to_str(char* buf, const dec80* x){
 #define INSERT_DOT() buf[i++]='.'
 	uint8_t i = 0;
 	uint8_t digit100;
@@ -787,7 +787,7 @@ void dec80_to_str(char* buf, const dec80* x){
 #endif
 		buf[0] = '0';
 		buf[1] = '\0';
-		return;
+		return 0;
 	}
 	//check sign of number
 	if (tmp.exponent < 0){
@@ -821,10 +821,8 @@ void dec80_to_str(char* buf, const dec80* x){
 	} else {
 		if (exponent == 0){
 			INSERT_DOT();
-			exponent--;
-		} else if (exponent > 0){
-			exponent--;
 		}
+		exponent--;
 	}
 	//print 2nd digit
 	buf[i] = (tmp.lsu[0] % 10) + '0';
@@ -836,10 +834,8 @@ void dec80_to_str(char* buf, const dec80* x){
 	if (!use_sci){
 		if (exponent == 0){
 			INSERT_DOT();
-			exponent--;
-		} else if (exponent > 0){
-			exponent--;
 		}
+		exponent--;
 	}
 	//print rest of significand
 	for (digit100 = 1 ; digit100 < DEC80_NUM_LSU; digit100++){
@@ -849,10 +845,8 @@ void dec80_to_str(char* buf, const dec80* x){
 		if (!use_sci){
 			if (exponent == 0){
 				INSERT_DOT();
-				exponent--;
-			} else if (exponent > 0){
-				exponent--;
 			}
+			exponent--;
 		}
 		//print 2nd digit
 		buf[i] = (tmp.lsu[digit100] % 10) + '0';
@@ -860,17 +854,17 @@ void dec80_to_str(char* buf, const dec80* x){
 		if (!use_sci){
 			if (exponent == 0){
 				INSERT_DOT();
-				exponent--;
-			} else if (exponent > 0){
-				exponent--;
 			}
+			exponent--;
 		}
 		//track trailing 0s
-		if (tmp.lsu[digit100] == 0 && (use_sci || exponent < -1)){
-			trailing_zeros += 2;
-		} else if (tmp.lsu[digit100] == 0 && (use_sci || exponent < 0)){
-			trailing_zeros += 1;
-		} else if (tmp.lsu[digit100] == 10 && (use_sci || exponent < 0)){
+		if (tmp.lsu[digit100] == 0 && (use_sci || exponent < 0)){
+			if (use_sci || exponent < -2){ //xx.00
+				trailing_zeros += 2;
+			} else if (exponent == -2){ //xx.0
+				trailing_zeros += 1;
+			}
+		} else if (tmp.lsu[digit100]%10 == 0 && (use_sci || exponent < 0)){
 			trailing_zeros = 1;
 		} else {
 			trailing_zeros = 0;
@@ -881,6 +875,7 @@ void dec80_to_str(char* buf, const dec80* x){
 	if (use_sci || exponent <= 0){
 		i -= trailing_zeros;
 	}
+	buf[i] = '\0';
 
 	//calculate exponent
 	exponent = get_exponent(&tmp); //base 100
@@ -888,19 +883,10 @@ void dec80_to_str(char* buf, const dec80* x){
 	printf ("  exponent (%d)", exponent);
 #endif
 	//print exponent
-	if (use_sci && exponent != 0){
-		buf[i] = 'E';
-		i++;
-		if (exponent < 0){
-			buf[i] = '-';
-			i++;
-			u32str(-exponent, &buf[i], 10); //adds null terminator automatically
-		} else {
-			u32str(exponent, &buf[i], 10); //adds null terminator automatically
-		}
+	if (use_sci){
+		return exponent;
 	} else {
-		//null terminate
-		buf[i] = '\0';
+		return 0;
 	}
 
 #ifdef DEBUG
@@ -912,5 +898,25 @@ void dec80_to_str(char* buf, const dec80* x){
 #endif
 }
 
+#ifdef DESKTOP
+//complete string including exponent
+void decn_to_str_complete(char* buf, const dec80* x){
+	int8_t exponent = decn_to_str(buf, x);
+	int i;
+	//find end of string
+	for (i = 0; buf[i] != '\0'; i++);
+	//add exponent
+	if (exponent != 0){
+		buf[i++] = 'E';
+		if (exponent < 0){
+			buf[i++] = '-';
+			u32str(-exponent, &buf[i], 10); //adds null terminator automatically
+		} else {
+			u32str(exponent, &buf[i], 10); //adds null terminator automatically
+		}
+	}
+
+}
+#endif
 
 

src/decn/decn.h

@@ -8,6 +8,7 @@
 #define SRC_DEC_DECN_H_
 
 #include <stdint.h>
+#include "../utils.h"
 
 #define DEC80_NUM_LSU 9
 
@@ -49,6 +50,11 @@ void div_decn(dec80* acc, const dec80* x);
 
 //buf should hold at least 18 + 4 + 5 + 1 = 28
 #define DECN_BUF_SIZE 28
-void dec80_to_str(char* buf, const dec80* x);
+int8_t decn_to_str(char* buf, const dec80* x);
+
+#ifdef DESKTOP
+//complete string including exponent
+void decn_to_str_complete(char* buf, const dec80* x);
+#endif
 
 #endif /* SRC_DEC_DECN_H_ */

src/decn/decn_test.c

@@ -13,169 +13,169 @@ int main(void){
 	dec80 acc, b;
 
 	build_dec80(&acc, "0.0009234567890123456", 7);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
 
 	build_dec80(&acc,  "9.234567890123456", 3);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
 
 	negate_decn(&acc);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("-acc:  %s\n", Buf);
 
 	build_dec80(&b, "-92.3456789012345678", 1);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("-acc:  %s\n", Buf);
 
 	//compare result of b - acc
 	add_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("b - a: %s\n", Buf);
 	printf("     : %s\n", "-10158.0246791358016");
 	dec80 diff;
 	build_dec80(&diff, "-1.01580246791358016", 4);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//new acc for acc - b test
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc: %s\n", Buf);
 	negate_decn(&b);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf(" -b: %s\n", Buf);
 
 	add_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	//compare result of new acc - b
 	printf("acc - b: %s\n", Buf);
 	printf("       : %s\n", "-9234.567890123456");
 	build_dec80(&diff, "-9.234567890123456", 3);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("       : %s\n\n", Buf);
 
 	//new acc and b for multiply test
 //	build_dec80(&acc,  "7", 2);
 	build_dec80(&acc,  "92.34567890123456", 2);
 	build_dec80(&b,   "-92.3456789012345678", 1);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	mult_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc*b: %s\n", Buf);
 	printf("     : %s\n", "-8527724.41172991849");
 	build_dec80(&diff, "-8.52772441172991849", 6);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//new acc and b for divide test
 	build_dec80(&acc,  "3.14", 88);
 	build_dec80(&b,   "-1.5", -2);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	div_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc/b: %s\n", Buf);
 	printf("     : %s\n", "-2.09333333333333334E90");
 	build_dec80(&diff, "-2.09333333333333334", 90);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//new acc and b for divide test
 	build_dec80(&acc,  "4", 0);
 	build_dec80(&b,   "4", 0);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	div_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc/b: %s\n", Buf);
-	printf("     : %s\n", "1.00000000");
+	printf("     : %s\n", "1.");
 	build_dec80(&diff, "1", 0);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//new acc and b for divide test
 	build_dec80(&acc,  "1", 0);
 	build_dec80(&b,   "3", 0);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	div_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc/b: %s\n", Buf);
 	printf("     : %s\n", "0.333333333333333336");
 	build_dec80(&diff, "3.33333333333333336", -1);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n", Buf);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//small fractions >= 1/10
 	build_dec80(&acc, "0.333", 0);
 	build_dec80(&b,   "3.33", -1);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("  a  : %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("  b  : %s\n", Buf);
 	negate_decn(&b);
 	add_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("a - b: %s\n", Buf);
 
 	//new acc and b for divide test
 	build_dec80(&acc,  "500", 0);
 	build_dec80(&b,   "99", 0);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	div_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc/b: %s\n", Buf);
 	printf("     : %s\n", "5.05050505050505055");
 	build_dec80(&diff, "5.05050505050505055", 0);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 	//new acc and b for divide test
 	build_dec80(&acc,  "500", 0);
 	build_dec80(&b,   "2", 0);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf(" acc: %s\n", Buf);
-	dec80_to_str(Buf, &b);
+	decn_to_str_complete(Buf, &b);
 	printf("   b: %s\n", Buf);
 	div_decn(&acc, &b);
-	dec80_to_str(Buf, &acc);
+	decn_to_str_complete(Buf, &acc);
 	printf("acc/b: %s\n", Buf);
-	printf("     : %s\n", "250.0");
+	printf("     : %s\n", "250.");
 	build_dec80(&diff, "250", 0);
 	negate_decn(&diff);
 	add_decn(&diff, &acc);
-	dec80_to_str(Buf, &diff);
+	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
 

src/main.c

@@ -105,7 +105,7 @@ static void latch_on(void)
 
 char Buf[DECN_BUF_SIZE];
 __xdata char EntryBuf[MAX_CHARS_PER_LINE + 1];
-__xdata uint8_t ExpBuf[2] = {0, 0};
+__xdata uint8_t ExpBuf[2];
 
 //#define DEBUG_UPTIME
 /*********************************************/
@@ -123,6 +123,7 @@ int main()
 	uint8_t entering_exp = ENTERING_DONE;
 	uint8_t no_lift = 0;
 	uint8_t exp_i = 0;
+	int8_t disp_exponent;
 #ifdef DEBUG_KEYS
 	uint8_t j = 0;
 	const uint8_t* keys;
@@ -139,6 +140,9 @@ int main()
 	KeyInit();
 	BACKLIGHT_ON(); //turn on led backlight
 
+	ExpBuf[0] = 0;
+	ExpBuf[1] = 0;
+
 #ifdef DEBUG_UPTIME
 	i = 0;
 #endif
@@ -157,12 +161,24 @@ int main()
 #else
 		//display y register on first line
 		if (entering_exp == ENTERING_DONE){
-			dec80_to_str(Buf, get_y());
+			disp_exponent = decn_to_str(Buf, get_y());
 		} else {
 			//display x on 1st line, entered number on 2nd line
-			dec80_to_str(Buf, get_x());
+			disp_exponent = decn_to_str(Buf, get_x());
+		}
+		if (disp_exponent == 0){
+			LCD_OutString(Buf, MAX_CHARS_PER_LINE);
+		} else { //have exponent to display
+			LCD_OutString(Buf, MAX_CHARS_PER_LINE - 3);
+			if (disp_exponent < 0){
+				TERMIO_PutChar('-');
+				disp_exponent = -disp_exponent;
+			} else {
+				TERMIO_PutChar(' ');
+			}
+			TERMIO_PutChar((disp_exponent / 10) + '0');
+			TERMIO_PutChar((disp_exponent % 10) + '0');
 		}
-		LCD_OutString(Buf, MAX_CHARS_PER_LINE);
 #endif //DEBUG_UPTIME
 
 #ifdef DEBUG_KEYS
@@ -208,8 +224,17 @@ int main()
 						//////////
 						case '0': {
 							if (entering_exp >= ENTERING_EXP){
-								ExpBuf[exp_i] = 0;
-								exp_i = (exp_i + 1) & 1;
+								if (exp_i == 0){
+									ExpBuf[0] = 0;
+									exp_i = 1;
+								} else {
+									ExpBuf[1] = ExpBuf[0];
+									ExpBuf[0] = 0;
+									exp_i++;
+									if (exp_i > 2){
+										exp_i = 1;
+									}
+								}
 							} else if (entering_exp == ENTERING_DONE){
 								entering_exp = ENTERING_SIGNIF;
 								EntryBuf[entry_i] = KEY_MAP[i_key];
@@ -230,8 +255,17 @@ int main()
 						case '8': //fallthrough
 						case '9': {
 							if (entering_exp >= ENTERING_EXP){
-								ExpBuf[exp_i] = KEY_MAP[i_key] - '0';
-								exp_i = (exp_i + 1) & 1;
+								if (exp_i == 0){
+									ExpBuf[0] = KEY_MAP[i_key] - '0';
+									exp_i = 1;
+								} else {
+									ExpBuf[1] = ExpBuf[0];
+									ExpBuf[0] = KEY_MAP[i_key] - '0';
+									exp_i++;
+									if (exp_i > 2){
+										exp_i = 1;
+									}
+								}
 							} else if (entering_exp == ENTERING_DONE){
 								entering_exp = ENTERING_SIGNIF;
 								EntryBuf[entry_i] = KEY_MAP[i_key];
@@ -349,8 +383,20 @@ int main()
 		//print X
 		LCD_ClearToEnd(0); //go to 2nd row
 		if (entering_exp == ENTERING_DONE){
-			dec80_to_str(Buf, get_x());
-			LCD_OutString(Buf, MAX_CHARS_PER_LINE);
+			disp_exponent = decn_to_str(Buf, get_x());
+			if (disp_exponent == 0){
+				LCD_OutString(Buf, MAX_CHARS_PER_LINE);
+			} else { //have exponent to display
+				LCD_OutString(Buf, MAX_CHARS_PER_LINE - 3);
+				if (disp_exponent < 0){
+					TERMIO_PutChar('-');
+					disp_exponent = -disp_exponent;
+				} else {
+					TERMIO_PutChar(' ');
+				}
+				TERMIO_PutChar((disp_exponent / 10) + '0');
+				TERMIO_PutChar((disp_exponent % 10) + '0');
+			}
 		} else if (entry_i == 0){
 			TERMIO_PutChar('0');
 		} else if (entering_exp < ENTERING_EXP){