forth: Word-ify "readword"

This commit is contained in:
Virgil Dupras 2020-03-19 21:40:35 -04:00
parent 5458a1f7ff
commit abb84b01db

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@ -42,9 +42,6 @@
; Flags for the "flag field" of the word structure
; IMMEDIATE word
.equ FLAG_IMMED 0
; This wordref is not a regular word (it's not preceeded by a name). It's one
; of the NUMBER, LIT, BRANCH etc. entities.
.equ FLAG_UNWORD 1
; *** Variables ***
.equ INITIAL_SP RAMSTART
@ -511,33 +508,6 @@ toword:
call readline
jr toword
; Read word from (INPUTPOS) and return, in HL, a null-terminated word.
; Advance (INPUTPOS) to the character following the whitespace ending the
; word.
; When we're at EOL, we call readline directly, so this call always returns
; a word.
readword:
call toword
push hl ; --> lvl 1. that's our result
.loop:
inc hl
ld a, (hl)
; special case: is A null? If yes, we will *not* inc A so that we don't
; go over the bounds of our input string.
or a
jr z, .noinc
cp ' '+1
jr nc, .loop
; we've just read a whitespace, HL is pointing to it. Let's transform
; it into a null-termination, inc HL, then set (INPUTPOS).
xor a
ld (hl), a
inc hl
.noinc:
ld (INPUTPOS), hl
pop hl ; <-- lvl 1. our result
ret ; Z set from XOR A
; Sets Z if (HL) == E and (HL+1) == D
HLPointsDE:
ld a, (hl)
@ -589,10 +559,9 @@ find:
; Z will be set if DE is zero
ret
; Spit name + prev in (HERE) and adjust (HERE) and (CURRENT)
; Spit name (in (HL)) + prev in (HERE) and adjust (HERE) and (CURRENT)
; HL points to new (HERE)
entryhead:
call readword
ld de, (HERE)
call strcpy
ex de, hl ; (HERE) now in HL
@ -1041,7 +1010,14 @@ COMPILE:
.dw COMPILE
.db 1 ; IMMEDIATE
DEFINE:
.dw nativeWord
.dw compiledWord
.dw WORD
.dw .define
.dw EXIT
.define:
.dw nativeWord
pop hl
call entryhead
ld de, compiledWord
call DEinHL
@ -1151,23 +1127,42 @@ LITN:
.dw LITN
.db 1 ; IMMEDIATE
LITS:
.dw nativeWord
.dw compiledWord
.dw .wrLIT
.dw WORD
.dw .scpy
.dw EXIT
.wrLIT:
.dw nativeWord
ld hl, (HERE)
ld de, LIT
call DEinHL
ex de, hl ; (HERE) in DE
call readword
ld (HERE), hl
jp next
.scpy:
.dw nativeWord
pop hl
ld de, (HERE)
call strcpyM
ld (HERE), de
jp next
.db "(find)"
.fill 1
.dw LITS
.db 0
FIND_:
.dw compiledWord
.dw WORD
.dw .find
.dw EXIT
.find:
.dw nativeWord
call readword
pop hl
call find
jr z, .found
; not found
@ -1226,14 +1221,35 @@ KEY:
push hl
jp next
; Read word from (INPUTPOS) and return, in HL, a null-terminated word.
; Advance (INPUTPOS) to the character following the whitespace ending the
; word.
; When we're at EOL, we call readline directly, so this call always returns
; a word.
.db "WORD"
.fill 3
.dw KEY
.db 0
WORD:
.dw nativeWord
call readword
push hl
call toword
push hl ; we already have our result
.loop:
inc hl
ld a, (hl)
; special case: is A null? If yes, we will *not* inc A so that we don't
; go over the bounds of our input string.
or a
jr z, .noinc
cp ' '+1
jr nc, .loop
; we've just read a whitespace, HL is pointing to it. Let's transform
; it into a null-termination, inc HL, then set (INPUTPOS).
xor a
ld (hl), a
inc hl
.noinc:
ld (INPUTPOS), hl
jp next
@ -1293,13 +1309,17 @@ PARSEI:
.dw PARSE
.db 0
CREATE:
.dw nativeWord
.dw compiledWord
.dw WORD
.dw .create
.dw EXIT
.create:
.dw nativeWord
pop hl
call entryhead
ld de, cellWord
ld (hl), e
inc hl
ld (hl), d
inc hl
call DEinHL
ld (HERE), hl
jp next