Implement compound assignment operators **= and >>>= (#2158)

src/asm/lexer.cpp

@@ -1683,9 +1683,6 @@ static Token yylex_NORMAL() {
 		case '-': // Either -= or SUB
 			return oneOrTwo('=', T_(POP_SUBEQ), T_(OP_SUB));
 
-		case '*': // Either *=, MUL, or EXP
-			return oneOrTwo('=', T_(POP_MULEQ), '*', T_(OP_EXP), T_(OP_MUL));
-
 		case '/': // Either /=, DIV, or a block comment
 			if (peek() == '*') {
 				shiftChar();
@@ -1716,6 +1713,14 @@ static Token yylex_NORMAL() {
 			}
 			return Token(T_(OP_LOGICNOT));
 
+		case '*': // Either *=, **=, MUL, or EXP
+			c = peek();
+			if (c == '*') {
+				shiftChar();
+				return oneOrTwo('=', T_(POP_EXPEQ), T_(OP_EXP));
+			}
+			return oneOrTwo('=', T_(POP_MULEQ), T_(OP_MUL));
+
 		case '<': // Either <<=, LT, LTE, or left shift
 			if (peek() == '<') {
 				shiftChar();
@@ -1723,13 +1728,6 @@ static Token yylex_NORMAL() {
 			}
 			return oneOrTwo('=', T_(OP_LOGICLE), T_(OP_LOGICLT));
 
-		case '>': // Either >>=, GT, GTE, or either kind of right shift
-			if (peek() == '>') {
-				shiftChar();
-				return oneOrTwo('=', T_(POP_SHREQ), '>', T_(OP_USHR), T_(OP_SHR));
-			}
-			return oneOrTwo('=', T_(OP_LOGICGE), T_(OP_LOGICGT));
-
 		case ':': // Either :, ::, or an anonymous label ref
 			c = peek();
 			if (c == '+' || c == '-') {
@@ -1737,6 +1735,19 @@ static Token yylex_NORMAL() {
 			}
 			return oneOrTwo(':', T_(DOUBLE_COLON), T_(COLON));
 
+			// Handle ambiguous 1-, 2-, 3-, or 4-char tokens
+
+		case '>': // Either >>=, >>>=, GT, GTE, or either kind of right shift
+			if (peek() == '>') {
+				shiftChar();
+				if (peek() == '>') {
+					shiftChar();
+					return oneOrTwo('=', T_(POP_USHREQ), T_(OP_USHR));
+				}
+				return oneOrTwo('=', T_(POP_SHREQ), T_(OP_SHR));
+			}
+			return oneOrTwo('=', T_(OP_LOGICGE), T_(OP_LOGICGT));
+
 			// Handle numbers
 
 		case '0': // Decimal, fixed-point, or base-prefix number

src/asm/parser.y

@@ -143,8 +143,9 @@
 %token POP_EQUAL "="
 %token POP_ADDEQ "+=" POP_SUBEQ "-="
 %token POP_MULEQ "*=" POP_DIVEQ "/=" POP_MODEQ "%="
+%token POP_EXPEQ "**="
 %token POP_ANDEQ "&=" POP_OREQ "|=" POP_XOREQ "^="
-%token POP_SHLEQ "<<=" POP_SHREQ ">>="
+%token POP_SHLEQ "<<=" POP_SHREQ ">>=" POP_USHREQ ">>>="
 
 // SM83 registers
 %token TOKEN_A "a"
@@ -640,6 +641,9 @@ compound_eq:
 	| POP_MODEQ {
 		$$ = RPN_MOD;
 	}
+	| POP_EXPEQ {
+		$$ = RPN_EXP;
+	}
 	| POP_XOREQ {
 		$$ = RPN_XOR;
 	}
@@ -655,6 +659,9 @@ compound_eq:
 	| POP_SHREQ {
 		$$ = RPN_SHR;
 	}
+	| POP_USHREQ {
+		$$ = RPN_USHR;
+	}
 ;
 
 align: