From cb92a82f4b3082d12d3f74bcc1670ea507fc78b5 Mon Sep 17 00:00:00 2001
From: Jeff Wang <jeff.wang@utexas.edu>
Date: Wed, 2 Oct 2019 22:47:53 -0400
Subject: [PATCH] add shift key and ability to calculate ln()

---
 src/calc.c | 17 +++++++++++++++++
 src/calc.h |  1 +
 src/main.c | 14 +++++++++++---
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/calc.c b/src/calc.c
index 43e7da6..f2b7abe 100644
--- a/src/calc.c
+++ b/src/calc.c
@@ -17,6 +17,7 @@
 #define STACK_T 3
 
 uint8_t NoLift = 0;
+uint8_t IsShifted = 0;
 
 //stack "grows" towards 0
 __xdata dec80 Stack[STACK_SIZE]; //0->x, 1->y, 2->z, 3->t initially
@@ -60,6 +61,10 @@ static void do_binary_op(void (*f_ptr)(void)){
 	pop();
 }
 
+static void toggle_shifted(void){
+	IsShifted ^= 1;
+}
+
 void process_cmd(char cmd){
 	//turn off backlight before start of processing
 	backlight_off();
@@ -108,6 +113,18 @@ void process_cmd(char cmd){
 				copy_decn(&stack(STACK_Y), &tmp);
 			}
 		} break;
+		//////////
+		case 'm':{ //use as shift
+			toggle_shifted();
+		} break;
+		//////////
+		case '8':{
+			if (IsShifted && !decn_is_nan(&stack(STACK_X))){ //ln(x)
+				copy_decn(&AccDecn, &stack(STACK_X));
+				ln_decn();
+				copy_decn(&stack(STACK_X), &AccDecn);
+				toggle_shifted();
+			}
 		} break;
 		//////////
 	} //switch(cmd)
diff --git a/src/calc.h b/src/calc.h
index 953b6cf..d79f18b 100644
--- a/src/calc.h
+++ b/src/calc.h
@@ -19,6 +19,7 @@ void process_cmd(char cmd);
 //push_decn is equivalent to "set_x()" if no_lift is true
 void push_decn(__xdata const char* signif_str, exp_t exponent);
 extern uint8_t NoLift;
+extern uint8_t IsShifted;
 
 void clear_x(void);
 __xdata dec80* get_x(void);
diff --git a/src/main.c b/src/main.c
index b0fb292..6655512 100644
--- a/src/main.c
+++ b/src/main.c
@@ -125,7 +125,7 @@ static void latch_on(void)
 
 __xdata char EntryBuf[MAX_CHARS_PER_LINE + 1];
 __xdata uint8_t ExpBuf[2];
-__xdata const char VER_STR[32+1] = "STC RPN         Calculator v1.03";
+__xdata const char VER_STR[32+1] = "STC RPN         Calculator v1.04";
 
 #ifdef DESKTOP
 static void print_entry_bufs(int entering_exp){
@@ -276,7 +276,9 @@ int main()
 				case '7': //fallthrough
 				case '8': //fallthrough
 				case '9': {
-					if (entering_exp >= ENTERING_EXP){
+					if (IsShifted){
+						process_cmd(KEY_MAP[i_key]);
+					} else if (entering_exp >= ENTERING_EXP){
 						if (exp_i == 0){
 							ExpBuf[0] = KEY_MAP[i_key] - '0';
 							exp_i = 1;
@@ -342,7 +344,7 @@ int main()
 				} break;
 				//////////
 				case 'c': {
-					if (entering_exp == ENTERING_DONE){
+					if (IsShifted || entering_exp == ENTERING_DONE){
 						//clear
 						clear_x();
 						NoLift = 1;
@@ -479,6 +481,12 @@ int main()
 			TERMIO_PutChar(ExpBuf[0] + '0');
 		}
 		LCD_ClearToEnd(1);
+
+		//print shifted status
+		if (IsShifted){
+			TERMIO_PutChar('^');
+		}
+
 #ifdef DESKTOP
 		print_lcd();
 		printf("entry_i=%d,exp_i=%d\n", entry_i, exp_i);