RPN calculator now supports negative values.

firmware/apps/rpn.c

@@ -12,8 +12,8 @@
 
 #define STACKSIZE 10
 
-static unsigned long stack[STACKSIZE];
-static unsigned long buffer=0;
+static long stack[STACKSIZE];
+static long buffer=0;
 static int bufferdirty=0;
 static unsigned int stacki=0;
 
@@ -109,7 +109,7 @@ void rpn_draw(){
 
 //! A button has been pressed for the calculator.
 int rpn_keypress(char ch){
-  unsigned long i, j;
+  long i, j;
 
   //Do nothing on a keyup event.
   if(!ch)

firmware/lcdtext.c

@@ -43,6 +43,8 @@ const int lcdmap[10][8]={
 
 //! Bit flags for each of the eight segments.
 enum lcdmappos {A=1, B=2, C=4, D=8, E=0x10, F=0x20, G=0x40, DP=0x80};
+
+
 //! Font for numbers.
 const int numfont[]={
   A|B|C|D|E|F,   //0
@@ -125,6 +127,10 @@ void lcd_char(int pos, char c){
   }else if(c==' '){
     lcd_cleardigit(pos);
     return;
+  }else if(c=='-'){
+    lcd_cleardigit(pos);
+    DRAWPOINT(lcdmap[pos][6]); //Set the G segment.
+    return;
   }else if(c=='.'){
     lcd_cleardigit(pos);
     setperiod(pos,1);
@@ -159,7 +165,7 @@ void lcd_string(const char *str){
 }
 
 //! Draws a decimal number on the screen.
-void lcd_number(long num){
+void lcd_unumber(long num){
   static long oldnum=0;
   static unsigned long bcd=0;
 
@@ -180,6 +186,17 @@ void lcd_number(long num){
   lcd_hex(bcd);
 }
 
+
+//! Draws a decimal number on the screen.
+void lcd_number(long num){
+  if(num<0){
+    lcd_unumber(0-num);
+    lcd_char(7,'-');
+  }else{
+    lcd_unumber(num);
+  }
+}
+
 //! Draws hex on the screen.
 void lcd_hex(long num){
   /* So in an ideal world, we'd have characters arranged nicely into