zasm: little code reorganisation
This commit is contained in:
Virgil Dupras
parent
95f53d0ce3
commit
6d4515cd03
@ -1,133 +0,0 @@
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; Parse the decimal char at A and extract it's 0-9 numerical value. Put the
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; result in A.
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;
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; On success, the carry flag is reset. On error, it is set.
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parseDecimalDigit:
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; First, let's see if we have an easy 0-9 case
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cp '0'
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ret c ; if < '0', we have a problem
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sub a, '0' ; our value now is valid if it's < 10
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cp 10 ; on success, C is set, which is the opposite
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; of what we want
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ccf ; invert C flag
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ret
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; Parse string at (HL) as a decimal value and return value in IX under the
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; same conditions as parseNumber.
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parseDecimal:
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push hl
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push de
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push bc
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ld ix, 0
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.loop:
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ld a, (hl)
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cp 0
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jr z, .end ; success!
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call parseDecimalDigit
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jr c, .error
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; Now, let's add A to IX. First, multiply by 10.
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ld d, ixh ; we need a copy of the initial copy for later
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ld e, ixl
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add ix, ix ; x2
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add ix, ix ; x4
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add ix, ix ; x8
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add ix, de ; x9
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add ix, de ; x10
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add a, ixl
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jr nc, .nocarry
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inc ixh
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.nocarry:
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ld ixl, a
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; We didn't bother checking for the C flag at each step because we
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; check for overflow afterwards. If ixh < d, we overflowed
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ld a, ixh
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cp d
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jr c, .error ; carry is set? overflow
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inc hl
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jr .loop
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.error:
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call JUMP_UNSETZ
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.end:
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pop bc
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pop de
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pop hl
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ret
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; Parse string at (HL) as a hexadecimal value and return value in IX under the
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; same conditions as parseNumber.
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parseHexadecimal:
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push hl
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xor a
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ld ixh, a
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inc hl ; get rid of "0x"
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inc hl
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call strlen
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cp 3
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jr c, .single
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cp 5
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jr c, .double
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; too long, error
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jr .error
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.double:
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call JUMP_PARSEHEXPAIR ; moves HL to last char of pair
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jr c, .error
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inc hl ; now HL is on first char of next pair
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ld ixh, a
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.single:
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call JUMP_PARSEHEXPAIR
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jr c, .error
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ld ixl, a
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cp a ; ensure Z
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jr .end
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.error:
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call JUMP_UNSETZ
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.end:
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pop hl
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ret
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; Sets Z if (HL) has a '0x' or '0X' prefix.
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hasHexPrefix:
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ld a, (hl)
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cp '0'
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ret nz
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push hl
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inc hl
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ld a, (hl)
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cp 'x'
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jr z, .end
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cp 'X'
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.end:
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pop hl
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ret
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; Parses the string at (HL) and returns the 16-bit value in IX.
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; As soon as the number doesn't fit 16-bit any more, parsing stops and the
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; number is invalid. If the number is valid, Z is set, otherwise, unset.
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parseNumber:
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call hasHexPrefix
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jr z, parseHexadecimal
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jr parseDecimal
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; Parse string in (HL) and return its numerical value whether its a number
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; literal or a symbol. Returns value in IX.
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; Sets Z if number or symbol is valid, unset otherwise.
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parseNumberOrSymbol:
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call parseNumber
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ret z
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; Not a number. Try symbol
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push de
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call symGetVal
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jr nz, .notfound ; Z already unset
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; Found! value in DE. We need it in IX
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ld ixh, d
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ld ixl, e
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; Z already set
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.notfound:
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pop de
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ret
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@ -44,8 +44,8 @@ jp zasmMain
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#include "util.asm"
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.equ IO_RAMSTART ZASM_RAMEND
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#include "io.asm"
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#include "tok.asm"
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#include "parse.asm"
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#include "literal.asm"
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#include "instr.asm"
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#include "directive.asm"
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.equ SYM_RAMSTART IO_RAMEND
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@ -1,146 +1,133 @@
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; *** Consts ***
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TOK_INSTR .equ 0x01
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TOK_DIRECTIVE .equ 0x02
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TOK_LABEL .equ 0x03
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TOK_EMPTY .equ 0xfe ; not a bad token, just an empty line
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TOK_BAD .equ 0xff
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.equ SCRATCHPAD_SIZE 0x20
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; *** Variables ***
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scratchpad:
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.fill SCRATCHPAD_SIZE
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; *** Code ***
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; Sets Z is A is ';' or null.
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isLineEndOrComment:
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cp ';'
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ret z
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or a ; cp 0
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ret
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; Sets Z is A is ' ' '\t' or ','
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isSep:
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cp ' '
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ret z
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cp 0x09
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ret z
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cp ','
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ret
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; Sets Z is A is ' ', ',', ';', CR, LF, or null.
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isSepOrLineEnd:
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call isSep
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ret z
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call isLineEndOrComment
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ret
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; Checks whether string at (HL) is a label, that is, whether it ends with a ":"
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; Sets Z if yes, unset if no.
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; Parse the decimal char at A and extract it's 0-9 numerical value. Put the
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; result in A.
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;
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; If it's a label, we change the trailing ':' char with a null char. It's a bit
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; dirty, but it's the easiest way to proceed.
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isLabel:
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; On success, the carry flag is reset. On error, it is set.
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parseDecimalDigit:
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; First, let's see if we have an easy 0-9 case
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cp '0'
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ret c ; if < '0', we have a problem
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sub a, '0' ; our value now is valid if it's < 10
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cp 10 ; on success, C is set, which is the opposite
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; of what we want
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ccf ; invert C flag
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ret
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; Parse string at (HL) as a decimal value and return value in IX under the
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; same conditions as parseNumber.
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parseDecimal:
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push hl
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ld a, ':'
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call JUMP_FINDCHAR
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ld a, (hl)
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cp ':'
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jr nz, .nomatch
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; We also have to check that it's our last char.
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inc hl
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ld a, (hl)
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or a ; cp 0
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jr nz, .nomatch ; not a null char following the :. no match.
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; We have a match!
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; Remove trailing ':'
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xor a ; Z is set
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ld (hl), a
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jr .end
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.nomatch:
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call JUMP_UNSETZ
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.end:
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pop hl
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ret
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; read word in (HL) and put it in (scratchpad), null terminated, for a maximum
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; of SCRATCHPAD_SIZE-1 characters. As a result, A is the read length. HL is
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; advanced to the next separator char.
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readWord:
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push bc
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push de
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ld de, scratchpad
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ld b, SCRATCHPAD_SIZE-1
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.loop:
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ld a, (hl)
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call isSepOrLineEnd
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jr z, .success
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call JUMP_UPCASE
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ld (de), a
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inc hl
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inc de
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djnz .loop
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.success:
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xor a
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ld (de), a
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ld a, SCRATCHPAD_SIZE-1
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sub a, b
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.end:
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pop de
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pop bc
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ret
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push bc
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; (HL) being a string, advance it to the next non-sep character.
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; Set Z if we could do it before the line ended, reset Z if we couldn't.
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toWord:
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ld ix, 0
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.loop:
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ld a, (hl)
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call isLineEndOrComment
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jr z, .error
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call isSep
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jr nz, .success
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cp 0
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jr z, .end ; success!
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call parseDecimalDigit
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jr c, .error
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; Now, let's add A to IX. First, multiply by 10.
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ld d, ixh ; we need a copy of the initial copy for later
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ld e, ixl
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add ix, ix ; x2
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add ix, ix ; x4
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add ix, ix ; x8
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add ix, de ; x9
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add ix, de ; x10
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add a, ixl
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jr nc, .nocarry
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inc ixh
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.nocarry:
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ld ixl, a
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; We didn't bother checking for the C flag at each step because we
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; check for overflow afterwards. If ixh < d, we overflowed
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ld a, ixh
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cp d
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jr c, .error ; carry is set? overflow
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inc hl
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jr .loop
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.error:
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call JUMP_UNSETZ
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ret
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.success:
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xor a ; ensure Z
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ret
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; Parse line in (HL) and read the next token in BC. The token is written on
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; two bytes (B and C). B is a token type (TOK_* constants) and C is an ID
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; specific to that token type.
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; Advance HL to after the read word.
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; If no token matches, TOK_BAD is written to B
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tokenize:
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call toWord
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jr nz, .emptyline
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call readWord
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push hl ; Save advanced HL for later
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ld hl, scratchpad
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call isLabel
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jr z, .label
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call getInstID
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jr z, .instr
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call getDirectiveID
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jr z, .direc
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; no match
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ld b, TOK_BAD
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jr .end
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.instr:
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ld b, TOK_INSTR
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jr .end
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.direc:
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ld b, TOK_DIRECTIVE
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jr .end
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.label:
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ld b, TOK_LABEL
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.end:
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ld c, a
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pop bc
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pop de
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pop hl
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ret
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.emptyline:
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ld b, TOK_EMPTY
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; no HL to pop, we jumped before the push
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; Parse string at (HL) as a hexadecimal value and return value in IX under the
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; same conditions as parseNumber.
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parseHexadecimal:
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push hl
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xor a
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ld ixh, a
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inc hl ; get rid of "0x"
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inc hl
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call strlen
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cp 3
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jr c, .single
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cp 5
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jr c, .double
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; too long, error
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jr .error
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.double:
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call JUMP_PARSEHEXPAIR ; moves HL to last char of pair
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jr c, .error
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inc hl ; now HL is on first char of next pair
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ld ixh, a
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.single:
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call JUMP_PARSEHEXPAIR
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jr c, .error
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ld ixl, a
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cp a ; ensure Z
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jr .end
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.error:
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call JUMP_UNSETZ
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.end:
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pop hl
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ret
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; Sets Z if (HL) has a '0x' or '0X' prefix.
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hasHexPrefix:
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ld a, (hl)
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cp '0'
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ret nz
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push hl
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inc hl
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ld a, (hl)
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cp 'x'
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jr z, .end
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cp 'X'
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.end:
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pop hl
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ret
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; Parses the string at (HL) and returns the 16-bit value in IX.
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; As soon as the number doesn't fit 16-bit any more, parsing stops and the
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; number is invalid. If the number is valid, Z is set, otherwise, unset.
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parseNumber:
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call hasHexPrefix
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jr z, parseHexadecimal
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jr parseDecimal
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; Parse string in (HL) and return its numerical value whether its a number
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; literal or a symbol. Returns value in IX.
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; Sets Z if number or symbol is valid, unset otherwise.
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parseNumberOrSymbol:
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call parseNumber
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ret z
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; Not a number. Try symbol
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push de
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call symGetVal
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jr nz, .notfound ; Z already unset
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; Found! value in DE. We need it in IX
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ld ixh, d
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ld ixl, e
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; Z already set
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.notfound:
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pop de
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ret
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146
apps/zasm/tok.asm
Normal file
146
apps/zasm/tok.asm
Normal file
@ -0,0 +1,146 @@
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; *** Consts ***
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TOK_INSTR .equ 0x01
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TOK_DIRECTIVE .equ 0x02
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TOK_LABEL .equ 0x03
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TOK_EMPTY .equ 0xfe ; not a bad token, just an empty line
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TOK_BAD .equ 0xff
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.equ SCRATCHPAD_SIZE 0x20
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; *** Variables ***
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scratchpad:
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.fill SCRATCHPAD_SIZE
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; *** Code ***
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; Sets Z is A is ';' or null.
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isLineEndOrComment:
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cp ';'
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ret z
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or a ; cp 0
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ret
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; Sets Z is A is ' ' '\t' or ','
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isSep:
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cp ' '
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ret z
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cp 0x09
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ret z
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cp ','
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ret
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; Sets Z is A is ' ', ',', ';', CR, LF, or null.
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isSepOrLineEnd:
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call isSep
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ret z
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call isLineEndOrComment
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ret
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; Checks whether string at (HL) is a label, that is, whether it ends with a ":"
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; Sets Z if yes, unset if no.
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;
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; If it's a label, we change the trailing ':' char with a null char. It's a bit
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; dirty, but it's the easiest way to proceed.
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isLabel:
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push hl
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ld a, ':'
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call JUMP_FINDCHAR
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ld a, (hl)
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cp ':'
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jr nz, .nomatch
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; We also have to check that it's our last char.
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inc hl
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ld a, (hl)
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or a ; cp 0
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jr nz, .nomatch ; not a null char following the :. no match.
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; We have a match!
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; Remove trailing ':'
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xor a ; Z is set
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ld (hl), a
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jr .end
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.nomatch:
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call JUMP_UNSETZ
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.end:
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pop hl
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ret
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; read word in (HL) and put it in (scratchpad), null terminated, for a maximum
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; of SCRATCHPAD_SIZE-1 characters. As a result, A is the read length. HL is
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; advanced to the next separator char.
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readWord:
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push bc
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push de
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ld de, scratchpad
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ld b, SCRATCHPAD_SIZE-1
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.loop:
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ld a, (hl)
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call isSepOrLineEnd
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jr z, .success
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call JUMP_UPCASE
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ld (de), a
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inc hl
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inc de
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djnz .loop
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.success:
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xor a
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ld (de), a
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ld a, SCRATCHPAD_SIZE-1
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sub a, b
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.end:
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pop de
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pop bc
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ret
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; (HL) being a string, advance it to the next non-sep character.
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; Set Z if we could do it before the line ended, reset Z if we couldn't.
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toWord:
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.loop:
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ld a, (hl)
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call isLineEndOrComment
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jr z, .error
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call isSep
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jr nz, .success
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inc hl
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jr .loop
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.error:
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call JUMP_UNSETZ
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ret
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.success:
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xor a ; ensure Z
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ret
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; Parse line in (HL) and read the next token in BC. The token is written on
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; two bytes (B and C). B is a token type (TOK_* constants) and C is an ID
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; specific to that token type.
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; Advance HL to after the read word.
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; If no token matches, TOK_BAD is written to B
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tokenize:
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call toWord
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jr nz, .emptyline
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call readWord
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push hl ; Save advanced HL for later
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ld hl, scratchpad
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call isLabel
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jr z, .label
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call getInstID
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jr z, .instr
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call getDirectiveID
|
||||
jr z, .direc
|
||||
; no match
|
||||
ld b, TOK_BAD
|
||||
jr .end
|
||||
.instr:
|
||||
ld b, TOK_INSTR
|
||||
jr .end
|
||||
.direc:
|
||||
ld b, TOK_DIRECTIVE
|
||||
jr .end
|
||||
.label:
|
||||
ld b, TOK_LABEL
|
||||
.end:
|
||||
ld c, a
|
||||
pop hl
|
||||
ret
|
||||
.emptyline:
|
||||
ld b, TOK_EMPTY
|
||||
; no HL to pop, we jumped before the push
|
||||
ret
|
||||
Loading…
Reference in New Issue
Block a user