Implement ISCONST, reporting compile-time constness

test/asm/isconst.asm

@@ -0,0 +1,29 @@
+
+TEST_NUM = 0
+
+test_expr: MACRO
+TEST_NUM = TEST_NUM + 1
+
+IS_CONST = ISCONST(\1)
+	PRINTT "Test #{d:TEST_NUM}: ISCONST reports {IS_CONST}\n"
+	IF (\1) || 1 ; Only test if the expression can be evaluated
+		WARN "Test #{d:TEST_NUM}: Compile-time constant"
+	ENDC
+ENDM
+
+	test_expr 1
+	test_expr UnknownLabel
+
+SECTION "fixed", WRAM0[$CAFE]
+
+FixedLabel:
+	ds 42
+	test_expr FixedLabel
+	test_expr @ - FixedLabel
+
+SECTION "floating", WRAMX
+
+FloatingLabel:
+	ds 69
+	test_expr FloatingLabel
+	test_expr @ - FloatingLabel