zasm: make symbol registry easily parametrizable

I'm about to split the global registry in two (labels and consts)
and the previous state of registry selection made things murky.
Now it's much better.

apps/zasm/symbol.asm

@@ -36,20 +36,28 @@
 .equ	SYM_LOC_VALUES		SYM_NAMES+SYM_BUFSIZE
 .equ	SYM_LOC_NAMES		SYM_LOC_VALUES+SYM_LOC_MAXCOUNT*2
 
-; Pointer to the currently selected registry
-.equ	SYM_CTX_NAMES		SYM_LOC_NAMES+SYM_LOC_BUFSIZE
-.equ	SYM_CTX_NAMESEND	SYM_CTX_NAMES+2
-.equ	SYM_CTX_VALUES		SYM_CTX_NAMESEND+2
-; Pointer, in (SYM_CTX_VALUES), to the result of the last symFind
-.equ	SYM_CTX_PTR		SYM_CTX_VALUES+2
+; Pointer to the active registry
+.equ	SYM_CTX			SYM_LOC_NAMES+SYM_LOC_BUFSIZE
 
+; Pointer, in the value list, to the result of the last _symFind
+.equ	SYM_CTX_PTR		SYM_CTX+2
 .equ	SYM_RAMEND		SYM_CTX_PTR+2
 
+; *** Registries ***
+; A symbol registry is a 6 bytes record with points to names and values of
+; one of the register.
+; It's 3 pointers: names, names end, values
+
+SYM_GLOBAL_REGISTRY:
+	.dw	SYM_NAMES, SYM_NAMES+SYM_BUFSIZE, SYM_VALUES
+
+SYM_LOCAL_REGISTRY:
+	.dw	SYM_LOC_NAMES, SYM_LOC_NAMES+SYM_LOC_BUFSIZE, SYM_LOC_VALUES
 ; *** Code ***
 
-; Advance HL to the beginning of the next symbol name in SYM_NAMES except if
-; (HL) is already zero, meaning we're at the end of the chain. In this case,
-; do nothing.
+; Assuming that HL points in to a symbol name list, advance HL to the beginning
+; of the next symbol name except if (HL) is already zero, meaning we're at the
+; end of the chain. In this case, do nothing.
 ; Sets Z if it succeeded, unset it if there is no next.
 _symNext:
 	xor	a
@@ -73,31 +81,17 @@ symInit:
 	; Continue to symSelectGlobalRegistry
 
 symSelectGlobalRegistry:
-	push	af
 	push	hl
-	ld	hl, SYM_NAMES
-	ld	(SYM_CTX_NAMES), hl
-	ld	hl, SYM_NAMES+SYM_BUFSIZE
-	ld	(SYM_CTX_NAMESEND), hl
-	ld	hl, SYM_VALUES
-	ld	(SYM_CTX_VALUES), hl
+	ld	hl, SYM_GLOBAL_REGISTRY
+	ld	(SYM_CTX), hl
 	pop	hl
-	pop	af
 	ret
 
 symSelectLocalRegistry:
-	push	af
 	push	hl
-	ld	hl, SYM_LOC_NAMES
-	ld	(SYM_CTX_NAMES), hl
-	ld	hl, SYM_LOC_NAMES+SYM_LOC_BUFSIZE
-	ld	(SYM_CTX_NAMESEND), hl
-	ld	hl, SYM_LOC_VALUES
-	ld	(SYM_CTX_VALUES), hl
-	ld	a, h
-	ld	a, l
+	ld	hl, SYM_LOCAL_REGISTRY
+	ld	(SYM_CTX), hl
 	pop	hl
-	pop	af
 	ret
 
 ; Sets Z according to whether label in (HL) is local (starts with a dot)
@@ -106,43 +100,51 @@ symIsLabelLocal:
 	cp	(hl)
 	ret
 
-; Place HL at the end of (SYM_CTX_NAMES) end (that is, at the point where we
-; have two consecutive null chars and DE at the corresponding position in
-; SYM_CTX_VALUES).
+; Given a registry in (IX), place HL at the end of its names that is, at the
+; point where we have two consecutive null chars and DE at the corresponding
+; position in its values.
 ; If we're within bounds, Z is set, otherwise unset.
-symNamesEnd:
-	push	ix
+_symNamesEnd:
+	push	iy
 	push	bc
 
-	ld	ix, (SYM_CTX_VALUES)
-	ld	hl, (SYM_CTX_NAMES)
-	ld	de, (SYM_CTX_NAMESEND)
+	; IY --> values
+	ld	l, (ix+4)
+	ld	h, (ix+5)
+	push	hl \ pop iy
+	; HL --> names
+	ld	l, (ix)
+	ld	h, (ix+1)
+	; DE --> names end
+	ld	e, (ix+2)
+	ld	d, (ix+3)
 .loop:
 	call	_symNext
 	jr	nz, .success	; We've reached the end of the chain.
-	inc	ix
-	inc	ix
+	inc	iy
+	inc	iy
 	; Are we out of bounds name-wise?
 	call	cpHLDE
 	jr	nc, .outOfBounds	; HL >= DE
-	; are we out of bounds value-wise? check if IX == (SYM_CTX_NAMES)
+	; are we out of bounds value-wise? check if IY == (IX)'s names
 	; Is is assumed that values are placed right before names
 	push	hl
-	push	ix \ pop bc
-	ld	hl, (SYM_CTX_NAMES)
+	push	iy \ pop bc
+	ld	l, (ix)
+	ld	h, (ix+1)
 	sbc	hl, bc
 	pop	hl
-	jr	z, .outOfBounds		; IX == (SYM_CTX_NAMES)
+	jr	z, .outOfBounds		; IY == (IX)'s names
 	jr	.loop
 .outOfBounds:
 	call	unsetZ
 	jr	.end
 .success:
-	push	ix \ pop de	; our values pos goes in DE
+	push	iy \ pop de	; our values pos goes in DE
 	cp	a		; ensure Z
 .end:
 	pop	bc
-	pop	ix
+	pop	iy
 	ret
 
 ; Register label in (HL) (minus the ending ":") into the symbol registry and
@@ -150,29 +152,33 @@ symNamesEnd:
 ; If successful, Z is set and A is the symbol index. Otherwise, Z is unset and
 ; A is an error code (ERR_*).
 symRegister:
-	call	symFind
+	push	ix		; --> lvl 1
+	ld	ix, (SYM_CTX)
+	call	_symFind
 	jr	z, .alreadyThere
 
-	push	hl	; will be used during processing. it's the symbol to add
-	push	de	; will be used during processing. it's our value.
+	push	hl	; --> lvl 2. it's the symbol to add
+	push	de	; --> lvl 3. it's our value.
 
 
 	; First, let's get our strlen
 	call	strlen
 	ld	c, a		; save that strlen for later
 
-	call	symNamesEnd
+	call	_symNamesEnd
 	jr	nz, .outOfMemory
 
 	; Is our new name going to make us go out of bounds?
-	push	hl
-	push	de
-		ld	de, (SYM_CTX_NAMESEND)
-		ld	a, c
-		call	addHL
-		call	cpHLDE
-	pop	de
-	pop	hl
+	push	hl		; --> lvl 4
+	push	de		; --> lvl 5
+	ld	e, (ix+2)
+	ld	d, (ix+3)
+	; DE --> names end
+	ld	a, c
+	call	addHL
+	call	cpHLDE
+	pop	de		; <-- lvl 5
+	pop	hl		; <-- lvl 4
 	jr	nc, .outOfMemory	; HL >= DE
 
 	; Success. At this point, we have:
@@ -183,11 +189,11 @@ symRegister:
 
 	; Let's start with the value.
 	push	hl \ pop ix	; save HL for later
-	pop	hl		; value to register
+	pop	hl		; <-- lvl 3. value to register
 	call	writeHLinDE	; write value where it goes.
 
 	; Good! now, the string.
-	pop	hl		; string to register
+	pop	hl		; <-- lvl 2. string to register
 	push	ix \ pop de	; string destination
 	; Copy HL into DE until we reach null char
 	call	strcpyM
@@ -196,15 +202,16 @@ symRegister:
 	; list. DE is already correctly placed, A is already zero
 	ld	(de), a
 
+	pop	ix		; <-- lvl 1
 	cp	a		; ensure Z
-	; Nothing to pop. We've already popped our stack in the lines above.
 	ret
 
 .outOfMemory:
 	ld	a, ERR_OOM
 	call	unsetZ
-	pop	de
-	pop	hl
+	pop	de		; <-- lvl 3
+	pop	hl		; <-- lvl 2
+	pop	ix		; <-- lvl 1
 	ret
 
 .alreadyThere:
@@ -224,51 +231,61 @@ symRegister:
 	; symbol names. So, if we end up in .alreadyThere during first pass,
 	; then it's an error condition. If it's not first pass, then we need
 	; to update our value.
+
+	; Let's pop our lvl 1 IX now, we don't need it any more.
+	pop	ix		; <-- lvl 1
+
 	call	zasmIsFirstPass
 	jr	z, .duplicateError
 	; Second pass. Don't error out, just update value
-	push	hl
+	push	hl		; --> lvl 1
 	ld	hl, (SYM_CTX_PTR)
 	ex	de, hl
 	call	writeHLinDE
-	pop	hl
+	pop	hl		; <-- lvl 1
 	cp	a		; ensure Z
 	ret
 .duplicateError:
 	ld	a, ERR_DUPSYM
 	jp	unsetZ		; return
 
-; Find name (HL) in (SYM_CTX_NAMES) and make (SYM_CTX_PTR) point to the
-; corresponding entry in (SYM_CTX_VALUES).
+; Assuming that IX points to a register context, find name HL in its names and
+; make the context pointer point to the corresponding entry in its values.
 ; If we find something, Z is set, otherwise unset.
-symFind:
-	push	ix
+_symFind:
+	push	iy
 	push	hl
 	push	de
 
 	ex	de, hl		; it's easier if HL is haystack and DE is
 				; needle.
-	ld	ix, (SYM_CTX_VALUES)
-	ld	hl, (SYM_CTX_NAMES)
+	; IY --> values
+	ld	l, (ix+4)
+	ld	h, (ix+5)
+	push	hl \ pop iy
+	; HL --> names
+	ld	l, (ix)
+	ld	h, (ix+1)
 .loop:
 	call	strcmp
 	jr	z, .match
 	; ok, next!
 	call	_symNext
 	jr	nz, .nomatch	; end of the chain, nothing found
-	inc	ix
-	inc	ix
+	inc	iy
+	inc	iy
 	jr	.loop
 .nomatch:
 	call	unsetZ
 	jr	.end
 .match:
-	ld	(SYM_CTX_PTR), ix
+	push	iy \ pop hl
+	ld	(SYM_CTX_PTR), hl
 	cp	a		; ensure Z
 .end:
 	pop	de
 	pop	hl
-	pop	ix
+	pop	iy
 	ret
 
 ; For a given symbol name in (HL), find it in the appropriate symbol register
@@ -277,15 +294,18 @@ symFind:
 ; always called when the global registry is selected. Therefore, we always
 ; reselect it afterwards.
 symFindVal:
+	push	ix
+	ld	ix, SYM_GLOBAL_REGISTRY
 	call	symIsLabelLocal
 	jp	nz, .notLocal
-	call	symSelectLocalRegistry
+	ld	ix, SYM_LOCAL_REGISTRY
 .notLocal:
-	call	symFind
+	call	_symFind
 	jr	nz, .end
 	; Found! let's fetch value
 	; Return value that (SYM_CTX_PTR) is pointing at in DE.
 	ld	de, (SYM_CTX_PTR)
 	call	intoDE
 .end:
-	jp	symSelectGlobalRegistry
+	pop	ix
+	ret

tools/tests/zasm/test6.asm

@@ -1,21 +0,0 @@
-.equ	RAMSTART	0x4000
-.equ	ACIA_CTL	0x80	; Control and status. RS off.
-.equ	ACIA_IO		0x81	; Transmit. RS on.
-
-#include "err.h"
-#include "core.asm"
-#include "parse.asm"
-.equ	ACIA_RAMSTART	RAMSTART
-#include "acia.asm"
-
-.equ	BLOCKDEV_RAMSTART	ACIA_RAMEND
-.equ	BLOCKDEV_COUNT		1
-#include "blockdev.asm"
-.dw	aciaGetC, aciaPutC, 0, 0
-
-.equ	STDIO_RAMSTART		BLOCKDEV_RAMEND
-#include "stdio.asm"
-
-.equ	SHELL_RAMSTART		STDIO_RAMEND
-.equ	SHELL_EXTRA_CMD_COUNT	0
-#include "shell.asm"