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zasm: add support for local labels
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@ -56,12 +56,16 @@ jp zasmMain
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; Read file through blockdev ID in H and outputs its upcodes through blockdev
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; ID in L.
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zasmMain:
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; Init I/O
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ld a, h
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ld de, IO_IN_GETC
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call JUMP_BLKSEL
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ld a, l
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ld de, IO_OUT_GETC
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call JUMP_BLKSEL
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; Init modules
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call symInit
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; First pass
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ld a, 1
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ld (ZASM_FIRST_PASS), a
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@ -155,14 +159,25 @@ parseLine:
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djnz .loopDirec
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jr .success
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.label:
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call zasmIsFirstPass
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jr nz, .success ; not in first pass? nothing to do
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; The string in (scratchpad) is a label with its trailing ':' removed.
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ld hl, scratchpad
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call zasmIsFirstPass
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jr z, .registerLabel ; When we encounter a label in the first
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; pass, we register it in the symbol
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; list
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; When we're not in the first pass, we set the context (if label is not
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; local) to that label.
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call symIsLabelLocal
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jr z, .success ; local? nothing to do.
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call symSetContext
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jr z, .success
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; NZ? this means that (HL) couldn't be found in symbol list. Weird
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jr .error
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.registerLabel:
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ld de, (curOutputOffset)
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call symRegister
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jr .success
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jr nz, .error
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; continue to .success
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.success:
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xor a ; ensure Z
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jr .end
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@ -29,7 +29,14 @@
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; index of the name, then go get the value at that index in SYM_VALUES.
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.equ SYM_NAMES SYM_VALUES+(SYM_MAXCOUNT*2)
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.equ SYM_RAMEND SYM_NAMES+SYM_BUFSIZE
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; Index of the symbol found during the last symSetContext call
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.equ SYM_CONTEXT_IDX SYM_NAMES+SYM_BUFSIZE
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; Pointer, in the SYM_NAMES buffer, of the string found during the last
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; symSetContext call
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.equ SYM_CONTEXT_PTR SYM_CONTEXT_IDX+1
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.equ SYM_RAMEND SYM_CONTEXT_PTR+2
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; *** Code ***
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@ -52,6 +59,20 @@ _symNext:
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cp a ; ensure Z
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ret
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symInit:
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xor a
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ld (SYM_NAMES), a
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ld (SYM_CONTEXT_IDX), a
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ld hl, SYM_CONTEXT_PTR
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ld (SYM_CONTEXT_PTR), hl
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ret
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; Sets Z according to whether label in (HL) is local (starts with a dot)
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symIsLabelLocal:
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ld a, '.'
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cp (hl)
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ret
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; Place HL at the end of SYM_NAMES end (that is, at the point where we have two
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; consecutive null chars. We return the index of that new name in A.
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; If we're within bounds, Z is set, otherwise unset.
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@ -148,6 +169,12 @@ symRegister:
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; If we find something, Z is set, otherwise unset.
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symFind:
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push hl
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call _symFind
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pop hl
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ret
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; Same as symFind, but leaks HL
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_symFind:
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push bc
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push de
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@ -155,10 +182,21 @@ symFind:
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call strlen
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ld c, a ; let's save that
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call symIsLabelLocal ; save Z for after the 3 next lines, which
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; doesn't touch flags. We need to call this now
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; before we lose HL.
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ex hl, de ; it's easier if HL is haystack and DE is
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; needle.
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ld b, 0
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ld hl, SYM_NAMES
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jr nz, .loop ; not local? jump right to loop
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; local? then we need to adjust B and HL
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ld hl, (SYM_CONTEXT_PTR)
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ld a, (SYM_CONTEXT_IDX)
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ld b, a
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xor a
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sub b
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ld b, a
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.loop:
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ld a, c ; recall strlen
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call JUMP_STRNCMP
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@ -179,7 +217,6 @@ symFind:
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.end:
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pop de
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pop bc
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pop hl
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ret
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; Return value associated with symbol index A into DE
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@ -194,3 +231,18 @@ symGetVal:
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ld d, (hl)
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pop hl
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ret
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; Find symbol name (HL) in the symbol list and set SYM_CONTEXT_* accordingly.
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; When symFind will be called with a symbol name starting with a '.', the search
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; will begin at that context instead of the beginning of the register.
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; Sets Z if symbol is found, unsets it if not.
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symSetContext:
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push hl
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call _symFind
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jr nz, .end ; Z already unset
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ld (SYM_CONTEXT_IDX), a
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ld (SYM_CONTEXT_PTR), hl
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; Z already set
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.end:
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pop hl
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ret
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20
apps/zasm/tests/test3.asm
Normal file
20
apps/zasm/tests/test3.asm
Normal file
@ -0,0 +1,20 @@
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; test local labels
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addDE:
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push af
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add a, e
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jr nc, .end ; no carry? skip inc
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inc d
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.end:
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ld e, a
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pop af
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ret
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addHL:
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push af
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add a, l
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jr nc, .end ; no carry? skip inc
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inc h
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.end:
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ld l, a
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pop af
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ret
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