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forth: give WORD its own buffer

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You'll soon see where I'm going with this...
This commit is contained in:
Virgil Dupras 2020-03-19 21:56:53 -04:00
parent 61abafbc1a
commit 2feb246334
1 changed files with 18 additions and 16 deletions
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34
forth/forth.asm
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@ -38,6 +38,9 @@
; Size of the readline buffer. If a typed line reaches this size, the line is ; Size of the readline buffer. If a typed line reaches this size, the line is
; flushed immediately (same as pressing return). ; flushed immediately (same as pressing return).
.equ INPT_BUFSIZE 0x40 .equ INPT_BUFSIZE 0x40
; Buffer where WORD copies its read word to. It's significantly larger than
; NAMELEN, but who knows, in a comment, we might have a very long word...
.equ WORD_BUFSIZE 0x20
; Flags for the "flag field" of the word structure ; Flags for the "flag field" of the word structure
; IMMEDIATE word ; IMMEDIATE word
@ -59,7 +62,8 @@
; runtime. ; runtime.
.equ PARSEPTR @+2 .equ PARSEPTR @+2
.equ INPTBUF @+2 .equ INPTBUF @+2
.equ RAMEND @+INPT_BUFSIZE .equ WORDBUF @+INPT_BUFSIZE
.equ RAMEND @+WORD_BUFSIZE
; (HERE) usually starts at RAMEND, but in certain situations, such as in stage0, ; (HERE) usually starts at RAMEND, but in certain situations, such as in stage0,
; (HERE) will begin at a strategic place. ; (HERE) will begin at a strategic place.
@ -1201,9 +1205,9 @@ KEY:
push hl push hl
jp next jp next
; Read word from (INPUTPOS) and return, in HL, a null-terminated word. ; Read word from (INPUTPOS), copy to WORDBUF, null-terminate, and return, make
; Advance (INPUTPOS) to the character following the whitespace ending the ; HL point to WORDBUF.
; word. ; Advance (INPUTPOS) to the character following the last copied character.
; When we're at EOL, we call readline directly, so this call always returns ; When we're at EOL, we call readline directly, so this call always returns
; a word. ; a word.
.db "WORD" .db "WORD"
@ -1213,22 +1217,20 @@ KEY:
WORD: WORD:
.dw nativeWord .dw nativeWord
call toword call toword
push hl ; we already have our result ld de, WORDBUF
push de ; we already have our result
.loop: .loop:
inc hl
ld a, (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 cp ' '+1
jr nc, .loop jr c, .loopend
; we've just read a whitespace, HL is pointing to it. Let's transform ld (de), a
; it into a null-termination, inc HL, then set (INPUTPOS).
xor a
ld (hl), a
inc hl inc hl
.noinc: inc de
jr .loop
.loopend:
; null-terminate the string.
xor a
ld (de), a
ld (INPUTPOS), hl ld (INPUTPOS), hl
jp next jp next