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zasm: deduplicate code

This commit is contained in:
Virgil Dupras 2019-05-13 19:47:34 -04:00
parent 746c86cbf8
commit 17dbee6a49

View File

@ -33,6 +33,25 @@
; *** 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.
; Sets Z if it succeeded, unset it if there is no next.
_symNext:
xor a
cp (hl)
jr nz, .do ; (HL) is not zero? we can advance.
; (HL) is zero? we're at the end of the chain.
call JUMP_UNSETZ
ret
.do:
; A is already 0
call JUMP_FINDCHAR ; find next null char
; go to the char after it.
inc hl
cp a ; ensure Z
ret
; Place HL at the end of SYM_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.
@ -44,13 +63,8 @@ symNamesEnd:
ld hl, SYM_NAMES
ld de, SYM_NAMES+SYM_BUFSIZE
.loop:
ld a, (hl)
or a ; cp 0
jr z, .success ; We've reached the end, Z is set, all good
xor a
call JUMP_FINDCHAR ; find next null char
; go to the char after it.
inc hl
call _symNext
jr nz, .success ; We've reached the end of the chain.
; Are we out of bounds?
call cpHLDE
jr nc, .outOfBounds ; HL >= DE
@ -146,17 +160,12 @@ symFind:
ld b, 0
ld hl, SYM_NAMES
.loop:
ld a, (hl)
or a ; cp 0
jr z, .nomatch
ld a, c
ld a, c ; recall strlen
call JUMP_STRNCMP
jr z, .match
; ok, next!
xor a
call JUMP_FINDCHAR ; find next null char
; go to the char after it.
inc hl
call _symNext
jr nz, .nomatch ; end of the chain, nothing found
djnz .loop
; exhausted djnz? no match
.nomatch:
@ -174,7 +183,6 @@ symFind:
ret
; Return value associated with symbol index A into DE
; Sets Z on success, unset on error.
symGetVal:
; our index is in A. Let's fetch the proper value
push hl
@ -185,5 +193,4 @@ symGetVal:
inc hl
ld d, (hl)
pop hl
cp a ; ensure Z
ret