shithub: rgbds

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Add unsigned right shift operator

--- a/include/linkdefs.h

+++ b/include/linkdefs.h

@@ -14,7 +14,7 @@

 #define RGBDS_OBJECT_VERSION_STRING "RGB%1u"

 #define RGBDS_OBJECT_VERSION_NUMBER 9U

-#define RGBDS_OBJECT_REV 8U

+#define RGBDS_OBJECT_REV 9U

 enum AssertionType {

 	ASSERT_WARN,

@@ -49,6 +49,7 @@

 	RPN_SHL			= 0x40,

 	RPN_SHR			= 0x41,

+	RPN_USHR		= 0x42,

 	RPN_BANK_SYM		= 0x50,

 	RPN_BANK_SECT		= 0x51,

--- a/include/opmath.h

+++ b/include/opmath.h

@@ -16,5 +16,6 @@

 int32_t op_exponent(int32_t base, uint32_t power);

 int32_t op_shift_left(int32_t value, int32_t amount);

 int32_t op_shift_right(int32_t value, int32_t amount);

+int32_t op_shift_right_unsigned(int32_t value, int32_t amount);

 #endif /* RGBDS_OP_MATH_H */

--- a/src/asm/lexer.c

+++ b/src/asm/lexer.c

@@ -1890,7 +1890,7 @@

 				return T_OP_LOGICLT;

 			}

-		case '>': /* Either >>=, GT, GTE, or right shift */

+		case '>': /* Either >>=, GT, GTE, or either kind of right shift */

 			switch (peek()) {

 			case '=':

 				shiftChar();

@@ -1897,11 +1897,16 @@

 				return T_OP_LOGICGE;

 			case '>':

 				shiftChar();

-				if (peek() == '=') {

+				switch (peek()) {

+				case '=':

 					shiftChar();

 					return T_POP_SHREQ;

+				case '>':

+					shiftChar();

+					return T_OP_USHR;

+				default:

+					return T_OP_SHR;

 				}

-				return T_OP_SHR;

 			default:

 				return T_OP_LOGICGT;

 			}

--- a/src/asm/parser.y

+++ b/src/asm/parser.y

@@ -534,7 +534,7 @@

 %token	T_OP_LOGICNE "!=" T_OP_LOGICEQU "=="

 %token	T_OP_ADD "+" T_OP_SUB "-"

 %token	T_OP_OR "|" T_OP_XOR "^" T_OP_AND "&"

-%token	T_OP_SHL "<<" T_OP_SHR ">>"

+%token	T_OP_SHL "<<" T_OP_SHR ">>" T_OP_USHR ">>>"

 %token	T_OP_MUL "*" T_OP_DIV "/" T_OP_MOD "%"

 %token	T_OP_NOT "~"

 %left	T_OP_LOGICOR

@@ -542,7 +542,7 @@

 %left	T_OP_LOGICGT T_OP_LOGICLT T_OP_LOGICGE T_OP_LOGICLE T_OP_LOGICNE T_OP_LOGICEQU

 %left	T_OP_ADD T_OP_SUB

 %left	T_OP_OR T_OP_XOR T_OP_AND

-%left	T_OP_SHL T_OP_SHR

+%left	T_OP_SHL T_OP_SHR T_OP_USHR

 %left	T_OP_MUL T_OP_DIV T_OP_MOD

 %precedence	NEG /* negation -- unary minus */

@@ -1476,6 +1476,9 @@

 		}

 		| relocexpr T_OP_SHR relocexpr {

 			rpn_BinaryOp(RPN_SHR, &$$, &$1, &$3);

+		}

+		| relocexpr T_OP_USHR relocexpr {

+			rpn_BinaryOp(RPN_USHR, &$$, &$1, &$3);

 		}

 		| relocexpr T_OP_MUL relocexpr {

 			rpn_BinaryOp(RPN_MUL, &$$, &$1, &$3);

--- a/src/asm/rgbasm.5

+++ b/src/asm/rgbasm.5

@@ -251,7 +251,9 @@

 .It Li ** Ta Exponent

 .It Li ~ + - Ta Unary complement/plus/minus

 .It Li * / % Ta Multiply/divide/modulo

-.It Li << >> Ta Shift left/right

+.It Li << Ta Shift left

+.It Li >> Ta Signed shift right (sign-extension)

+.It Li >>> Ta Unsigned shift right (zero-extension)

 .It Li & \&| ^ Ta Binary and/or/xor

 .It Li + - Ta Add/subtract

 .It Li != == <= >= < > Ta Comparison

--- a/src/asm/rpn.c

+++ b/src/asm/rpn.c

@@ -421,6 +421,19 @@

 			expr->val = op_shift_right(src1->val, src2->val);

 			break;

+		case RPN_USHR:

+			if (src2->val < 0)

+				warning(WARNING_SHIFT_AMOUNT,

+					"Shifting right by negative amount %" PRId32 "\n",

+					src2->val);

+

+			if (src2->val >= 32)

+				warning(WARNING_SHIFT_AMOUNT,

+					"Shifting right by large amount %" PRId32 "\n",

+					src2->val);

+

+			expr->val = op_shift_right_unsigned(src1->val, src2->val);

+			break;

 		case RPN_MUL:

 			expr->val = uleft * uright;

 			break;

--- a/src/link/patch.c

+++ b/src/link/patch.c

@@ -265,6 +265,10 @@

 			value = popRPN();

 			value = op_shift_right(popRPN(), value);

 			break;

+		case RPN_USHR:

+			value = popRPN();

+			value = op_shift_right_unsigned(popRPN(), value);

+			break;

 		case RPN_BANK_SYM:

 			value = 0;

--- a/src/opmath.c

+++ b/src/opmath.c

@@ -86,3 +86,18 @@

 	// undefined, so use a left shift manually sign-extended

 	return ((uint32_t)value >> amount) | amount_high_bits;

 }

+

+int32_t op_shift_right_unsigned(int32_t value, int32_t amount)

+{

+	// Repeat the easy cases here to avoid INT_MIN funny business

+	if (amount == 0)

+		return value;

+	if (value == 0 || amount <= -32)

+		return 0;

+	if (amount > 31)

+		return (value < 0) ? -1 : 0;

+	if (amount < 0)

+		return op_shift_left(value, -amount);

+

+	return (uint32_t)value >> amount;

+}

--- a/src/rgbds.5

+++ b/src/rgbds.5

@@ -241,6 +241,7 @@

 .It Li $35 Ta Li <= comparison

 .It Li $40 Ta Li << operator

 .It Li $41 Ta Li >> operator

+.It Li $42 Ta Li >>> operator

 .It Li $50 Ta Li BANK(symbol) ,

 a

 .Ar LONG

--- a/test/asm/shift.asm

+++ b/test/asm/shift.asm

@@ -1,6 +1,6 @@

 macro test

 	; Test the rpn system, as well as the linker...

-	DEF expr EQUS STRRPL(STRRPL("\1 + zero)", "<<", "<< ("), ">>", ">> (")

+	DEF expr EQUS STRRPL(STRRPL("\1 + zero)", "<< ", "<< ("), ">> ", ">> (")

 	dl expr

 	PURGE expr

@@ -23,6 +23,9 @@

 	test -4 >> 1

 	test -4 >> 2

 	test -1 >> -9001

+

+	test $DEADBEEF >> 1

+	test $DEADBEEF >>> 1

 SECTION "Zero", ROM0[0]

 zero:

--- a/test/asm/shift.err

+++ b/test/asm/shift.err

@@ -24,3 +24,5 @@

     Shifting right negative value -1

 warning: shift.asm(25) -> shift.asm::test(8): [-Wshift-amount]

     Shifting right by negative amount -9001

+warning: shift.asm(27) -> shift.asm::test(8): [-Wshift]

+    Shifting right negative value -559038737

--- a/test/asm/shift.out

+++ b/test/asm/shift.out

@@ -10,3 +10,5 @@

 -4 >> 1 = $FFFFFFFE

 -4 >> 2 = $FFFFFFFF

 -1 >> -9001 = $0

+$DEADBEEF >> 1 = $EF56DF77

+$DEADBEEF >>> 1 = $6F56DF77

binary files a/test/asm/shift.out.bin b/test/asm/shift.out.bin differ