mirror of https://github.com/hsoft/collapseos.git
98 lines
1.7 KiB
NASM
98 lines
1.7 KiB
NASM
; Whether A is a separator or end-of-string (null or ':')
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isSepOrEnd:
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or a
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ret z
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cp ':'
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ret z
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; continue to isSep
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; Sets Z is A is ' ' or '\t' (whitespace)
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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
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; Expect at least one whitespace (0x20, 0x09) at (HL), and then advance HL
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; until a non-whitespace character is met.
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; HL is advanced to the first non-whitespace char.
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; Sets Z on success, unset on failure.
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; Failure is either not having a first whitespace or reaching the end of the
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; string.
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; Sets Z if we found a non-whitespace char, unset if we found the end of string.
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rdSep:
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ld a, (hl)
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call isSep
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ret nz ; failure
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.loop:
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inc hl
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ld a, (hl)
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call isSep
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jr z, .loop
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call isSepOrEnd
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jp z, .fail ; unexpected EOL. fail
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cp a ; ensure Z
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ret
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.fail:
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; A is zero at this point
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inc a ; unset Z
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ret
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; Advance HL to the next separator or to the end of string.
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toSepOrEnd:
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ld a, (hl)
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call isSepOrEnd
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ret z
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inc hl
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jr toSepOrEnd
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; Advance HL to the end of the line, that is, either a null terminating char
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; or the ':'.
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; Sets Z if we met a null char, unset if we met a ':'
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toEnd:
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ld a, (hl)
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or a
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ret z
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cp ':'
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jr z, .havesep
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inc hl
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call skipQuoted
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jr toEnd
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.havesep:
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inc a ; unset Z
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ret
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; Read (HL) until the next separator and copy it in (DE)
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; DE is preserved, but HL is advanced to the end of the read word.
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rdWord:
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push af
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push de
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.loop:
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ld a, (hl)
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call isSepOrEnd
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jr z, .stop
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ld (de), a
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inc hl
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inc de
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jr .loop
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.stop:
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xor a
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ld (de), a
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pop de
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pop af
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ret
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; Read word from HL in SCRATCHPAD and then intepret that word as an expression.
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; Put the result in IX.
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; Z for success.
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; TODO: put result in DE
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rdExpr:
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ld de, SCRATCHPAD
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call rdWord
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push hl
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ex de, hl
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call parseExpr
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push de \ pop ix
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pop hl
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ret
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