zasm: Constants now override labels at all times

Will be important for a mega-commit I'm preparing.

apps/zasm/README.md

@@ -76,6 +76,12 @@ forward-reference labels.
 
 However, they *cannot* forward-reference other constants.
 
+When defining a constant, if the symbol specified has already been defined, no
+error occur and the first value defined stays intact. This allows for "user
+override" of programs.
+
+It's also important to note that constants always override labels, regardless
+of declaration order.
 
 ## Expressions
 
@@ -119,11 +125,7 @@ allowed. An included file cannot have an `.inc` directive.
 
 **.equ**: Binds a symbol named after the first parameter to the value of the
           expression written as the second parameter. Example:
-          `.equ foo 0x42+'A'`
+          `.equ foo 0x42+'A'`. See "Constants" above.
-          
-If the symbol specified has already been defined, no error occur and
-the first value defined stays intact. This allows for "user override"
-of programs.
           
 **.fill**: Outputs the number of null bytes specified by its argument, an
            expression. Often used with `$` to fill our binary up to a certain

apps/zasm/symbol.asm

@@ -219,13 +219,13 @@ symFindVal:
 	push	ix
 	call	symIsLabelLocal
 	jr	z, .local
-	; global. Let's try labels first, then consts
+	; global. Let's try consts first, then symbols
 	push	hl		; --> lvl 1. we'll need it again if not found.
-	ld	ix, SYM_GLOBAL_REGISTRY
+	ld	ix, SYM_CONST_REGISTRY
 	call	_symFind
 	pop	hl		; <-- lvl 1
 	jr	z, .found
-	ld	ix, SYM_CONST_REGISTRY
+	ld	ix, SYM_GLOBAL_REGISTRY
 	call	_symFind
 	jr	nz, .end
 .found:

tools/tests/unit/test_core.asm

@@ -2,8 +2,11 @@ jp	test
 
 .inc "core.asm"
 
+dummyLabel:
 testNum:	.db 1
 
+.equ	dummyLabel	0x42
+
 test:
 	ld	hl, 0xffff
 	ld	sp, hl
@@ -30,6 +33,13 @@ test:
 	jp	p, fail		; negative
 	call	nexttest
 
+	; Test that .equ can override label
+	ld	a, 0x42
+	ld	hl, dummyLabel
+	cp	l
+	jp	nz, fail
+	call	nexttest
+
 	; *** cpHLDE ***
 	ld	hl, 0x42
 	ld	de, 0x42