126 lines
2.4 KiB
NASM
126 lines
2.4 KiB
NASM
; Return address of scratchpad in HL
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pad:
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ld hl, (HERE)
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ld a, PADDING
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jp addHL
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; Read word from (INPUTPOS) and return, in HL, a null-terminated word.
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; Advance (INPUTPOS) to the character following the whitespace ending the
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; word.
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; Z set of word was read, unset if end of line.
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readword:
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ld hl, (INPUTPOS)
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; skip leading whitespace
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dec hl ; offset leading "inc hl"
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.loop1:
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inc hl
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ld a, (hl)
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or a
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jr z, .empty
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cp ' '+1
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jr c, .loop1
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push hl ; --> lvl 1. that's our result
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.loop2:
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inc hl
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ld a, (hl)
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; special case: is A null? If yes, we will *not* inc A so that we don't
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; go over the bounds of our input string.
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or a
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jr z, .noinc
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cp ' '+1
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jr nc, .loop2
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; we've just read a whitespace, HL is pointing to it. Let's transform
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; it into a null-termination, inc HL, then set (INPUTPOS).
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xor a
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ld (hl), a
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inc hl
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.noinc:
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ld (INPUTPOS), hl
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pop hl ; <-- lvl 1. our result
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ret ; Z set from XOR A
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.empty:
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ld (hl), a
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inc a ; unset Z
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ret
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; For DE pointing to a dict entry, set DE to point to the previous entry.
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; Z is set if DE point to 0 (no entry). NZ if not.
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prev:
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push hl ; --> lvl 1
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ld hl, NAMELEN ; prev field offset
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add hl, de
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ex de, hl
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pop hl ; <-- lvl 1
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call intoDE
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; DE points to prev. Is it zero?
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xor a
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or d
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or e
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; Z will be set if DE is zero
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ret
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; Find the entry corresponding to word where (HL) points to and sets DE to
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; point to that entry.
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; Z if found, NZ if not.
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find:
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ld de, (CURRENT)
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.inner:
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ld a, NAMELEN
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call strncmp
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ret z ; found
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call prev
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jr nz, .inner
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; Z set? end of dict unset Z
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inc a
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ret
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; Write compiled data from HL into IY, advancing IY at the same time.
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wrCompHL:
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ld (iy), l
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inc iy
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ld (iy), h
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inc iy
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ret
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; Compile word string at (HL) and write down its compiled version in IY,
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; advancing IY to the byte next to the last written byte.
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; Set Z on success, unset on failure.
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compile:
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call find
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jr nz, .maybeNum
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ret nz
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; DE is a word offset, we need a code link
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ld hl, CODELINK_OFFSET
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add hl, de
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xor a ; set Z
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jr wrCompHL
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.maybeNum:
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call parseLiteral
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ret nz
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; a valid number!
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ld hl, NUMBER
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call wrCompHL
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ex de, hl ; number in HL
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jr wrCompHL
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; Spit name + prev in (HERE) and adjust (HERE) and (CURRENT)
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; HL points to new (HERE)
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; Set Z if name could be read, NZ if not
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entryhead:
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call readword
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ret nz
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ld de, (HERE)
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call strcpy
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ex de, hl ; (HERE) now in HL
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ld de, (CURRENT)
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ld (CURRENT), hl
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ld a, NAMELEN
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call addHL
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ld (hl), e
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inc hl
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ld (hl), d
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inc hl
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ld (HERE), hl
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xor a ; set Z
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ret
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