zasm: add support for "$" symbol

Allows for the ".fill x-$" pattern.

apps/zasm/parse.asm

@@ -226,7 +226,13 @@ parseLiteral:
 parseNumberOrSymbol:
 	call	parseLiteral
 	ret	z
-	; Not a number. Try symbol
+	; Not a number. Try PC
+	push	de
+	ld	de, .sDollar
+	call	strcmp
+	pop	de
+	jr	z, .returnPC
+	; Not PC either, try symbol
 	call	symSelect
 	call	symFind
 	jr	nz, .notfound
@@ -244,3 +250,12 @@ parseNumberOrSymbol:
 	; Otherwise return error. Z is already unset, so in fact, this is the
 	; same as jumping to zasmIsFirstPass
 	jp	zasmIsFirstPass
+
+.returnPC:
+	push	hl
+	call	zasmGetPC
+	push	hl \ pop ix
+	pop	hl
+	ret
+.sDollar:
+	.db	'$', 0

tools/emul/user.h

@@ -1,5 +1,5 @@
 .equ    USER_CODE       0x4800
-.equ    USER_RAMSTART   0x5800
+.equ    USER_RAMSTART   0x6000
 .equ    FS_HANDLE_SIZE  8
 
 ; *** JUMP TABLE ***

tools/tests/unit/test_expr.asm

@@ -13,6 +13,9 @@ jp	test
 zasmIsFirstPass:
 	jp	unsetZ
 
+zasmGetPC:
+	ret
+
 testNum:	.db 1
 
 s1:		.db "2+2", 0

tools/tests/unit/test_parse.asm

@@ -3,6 +3,9 @@ jp	test
 #include "core.asm"
 #include "parse.asm"
 
+zasmGetPC:
+	ret
+
 testNum:	.db 1
 
 sFoo:		.db "Foo", 0

tools/tests/unit/test_parse_z.asm

@@ -6,6 +6,7 @@ jp	test
 #include "zasm/parse.asm"
 
 ; mocks. aren't used in tests
+zasmGetPC:
 zasmIsFirstPass:
 symSelect:
 symFind:

tools/tests/zasm/test1.asm

@@ -27,4 +27,4 @@ label2: .dw	0x42
 	rlc	c
 	cp	'-'
 	sbc	hl, de
-.fill	0x10
+.fill	0x50-$