fix bug for entering numbers such as 0.01

README.md

@@ -13,10 +13,10 @@ This is a replacement firmware for the [diyleyuan calculator](http://www.diyleyu
 - CMakeLists.txt is for building the Qt desktop application.
 	- (still a work in progress)
 	- build similarly to other cmake projects:
-		- mkdir build_qt && cd build_qt
-		- cmake -DCMAKE_BUILD_TYPE=Debug -G "Eclipse CDT4 - Ninja" ..
+		- `mkdir build_qt && cd build_qt`
+		- `cmake -DCMAKE_BUILD_TYPE=Debug -G "Eclipse CDT4 - Ninja" ..`
 			- (you can choose a different generator, I prefer using Ninja to build, because it's fast)
-		- ninja
+		- `ninja`
 
 # Installing
 The STC microcontroller used has a bootloader permanently stored in ROM that allows downloading new firmware over a serial port. You can re-program it using a USB-to-logic-level-serial (5V) dongle, and the stcgal program. WARNING: a lot of USB-to-logic-level-serial dongles are for 3.3V logic levels. The diyleyuan calculator runs at 5V to make it easier to power/drive the LCD display. You have a couple of options:
@@ -112,7 +112,7 @@ The calculator uses RPN. To calculate (2+3)/(9^2), enter:
 - `*`
 - `÷`
 
-The = key is used for Enter. There is automatic stack lift so that `9`, `Enter`, `*` is equivalent to 9^2.
+The = key is used for Enter. There is automatic stack lift so that `9`, `Enter`, `*` is equivalent to 9^2. The stack is a classic 4-level RPN stack, where the T register duplicates.
 
 ## Keys
 The keys on the original calculator map as follows:

src/CMakeLists.txt

@@ -8,3 +8,6 @@ target_link_libraries(calc Qt5::Widgets)
 
 add_executable(keytest key.c)
 target_compile_definitions(keytest PRIVATE KEY_TEST_APP=1)
+
+add_executable(decn_test decn/decn_test.c utils.c)
+target_link_libraries(decn_test decn)

src/decn/decn.c

@@ -191,11 +191,6 @@ void build_dec80(dec80* dest, const char* signif_str, int16_t exponent){
 				}
 			}
 			nibble_i++;
-			//track number of digits R of decimal point
-			//must do this before changing is_zero
-			if (curr_sign == SIGN_ZERO_SEEN_POINT || curr_sign == SIGN_NEG_ZERO_SEEN_POINT){
-				num_lr_points = -1;
-			}
 			//track sign
 			if (curr_sign == SIGN_ZERO){
 				curr_sign = SIGN_POS;

src/decn/decn_test.c

@@ -195,6 +195,23 @@ int main(void){
 	decn_to_str_complete(Buf, &diff);
 	printf("     : %s\n\n", Buf);
 
+	//new acc and b for divide test
+	build_dec80(&acc,  "0.02", 0);
+	build_dec80(&b,   "0.03", 0);
+	decn_to_str_complete(Buf, &acc);
+	printf(" acc: %s\n", Buf);
+	decn_to_str_complete(Buf, &b);
+	printf("   b: %s\n", Buf);
+	div_decn(&acc, &b);
+	decn_to_str_complete(Buf, &acc);
+	printf("acc/b: %s\n", Buf);
+	printf("     : %s\n", "0.666666666666666672");
+	build_dec80(&diff, "0.666666666666666672", 0);
+	negate_decn(&diff);
+	add_decn(&diff, &acc);
+	decn_to_str_complete(Buf, &diff);
+	printf("     : %s\n\n", Buf);
+
 
 	return 0;
 }