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zasm: add one layer of indirection in symbol registry 

We'll need it for an upcoming "local labels" registry.
This commit is contained in:
Virgil Dupras 2019-05-15 14:30:41 -04:00
parent fa28d64278
commit a2b5b1efab
1 changed files with 21 additions and 10 deletions
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31
apps/zasm/symbol.asm
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@ -36,7 +36,12 @@
; symSetContext call
.equ SYM_CONTEXT_PTR SYM_CONTEXT_IDX+1
.equ SYM_RAMEND SYM_CONTEXT_PTR+2
; Pointer to the currently selected registry
.equ SYM_CTX_NAMES SYM_CONTEXT_PTR+2
.equ SYM_CTX_NAMESEND SYM_CTX_NAMES+2
.equ SYM_CTX_VALUES SYM_CTX_NAMESEND+2
.equ SYM_RAMEND SYM_CTX_VALUES+2
; *** Code ***
@ -65,6 +70,12 @@ symInit:
ld (SYM_CONTEXT_IDX), a
ld hl, SYM_CONTEXT_PTR
ld (SYM_CONTEXT_PTR), 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
ret
; Sets Z according to whether label in (HL) is local (starts with a dot)
@ -73,7 +84,7 @@ symIsLabelLocal:
cp (hl)
ret
; Place HL at the end of SYM_NAMES end (that is, at the point where we have two
; Place HL at the end of (SYM_CTX_NAMES) end (that is, at the point where we have two
; consecutive null chars. We return the index of that new name in A.
; If we're within bounds, Z is set, otherwise unset.
symNamesEnd:
@ -81,8 +92,8 @@ symNamesEnd:
push de
ld b, 0
ld hl, SYM_NAMES
ld de, SYM_NAMES+SYM_BUFSIZE
ld hl, (SYM_CTX_NAMES)
ld de, (SYM_CTX_NAMESEND)
.loop:
call _symNext
jr nz, .success ; We've reached the end of the chain.
@ -125,7 +136,7 @@ symRegister:
; Is our new name going to make us go out of bounds?
push hl
push de
ld de, SYM_NAMES+SYM_BUFSIZE
ld de, (SYM_CTX_NAMESEND)
ld a, c
call JUMP_ADDHL
call cpHLDE
@ -144,17 +155,17 @@ symRegister:
; I'd say we're pretty good just about now. What we need to do is to
; save the value in our original DE that is just on top of the stack
; into the proper index in SYM_VALUES. Our index, remember, is
; into the proper index in (SYM_CTX_VALUES). Our index, remember, is
; currently in A'.
ex af, af'
pop de
push de ; push it right back to avoid stack imbalance
ld hl, SYM_VALUES
ld hl, (SYM_CTX_VALUES)
call JUMP_ADDHL
call JUMP_ADDHL ; twice because our values are words
; Everything is set! DE is our value HL points to the proper index in
; SYM_VALUES. Let's just write it (little endian).
; (SYM_CTX_VALUES). Let's just write it (little endian).
ld (hl), e
inc hl
ld (hl), d
@ -165,7 +176,7 @@ symRegister:
pop hl
ret
; Find name (HL) in SYM_NAMES and returns matching index in A.
; Find name (HL) in (SYM_CTX_NAMES) and returns matching index in A.
; If we find something, Z is set, otherwise unset.
symFind:
push hl
@ -188,7 +199,7 @@ _symFind:
ex hl, de ; it's easier if HL is haystack and DE is
; needle.
ld b, 0
ld hl, SYM_NAMES
ld hl, (SYM_CTX_NAMES)
jr nz, .loop ; not local? jump right to loop
; local? then we need to adjust B and HL
ld hl, (SYM_CONTEXT_PTR)