collapseos/apps/ed/io.asm
2019-07-13 11:29:06 -04:00

44 lines
751 B
NASM

; io - handle ed's I/O
; *** Consts ***
;
; Max length of a line
.equ IO_MAXLEN 0x7f
; *** Variables ***
; Buffer for lines read from I/O.
.equ IO_LINE IO_RAMSTART
.equ IO_RAMEND IO_LINE+IO_MAXLEN+1 ; +1 for null
; *** Code ***
; Given an offset HL, read the line in IO_LINE, without LF and null terminates
; it. Make HL point to IO_LINE.
ioGetLine:
push af
push de
push bc
ld de, 0 ; limit ourselves to 16-bit for now
xor a ; absolute seek
call blkSeek
ld hl, IO_LINE
ld b, IO_MAXLEN
.loop:
call blkGetC
jr nz, .loopend
or a ; null? hum, weird. same as LF
jr z, .loopend
cp 0x0a
jr z, .loopend
ld (hl), a
inc hl
djnz .loop
.loopend:
; null-terminate the string
xor a
ld (hl), a
ld hl, IO_LINE
pop bc
pop de
pop af
ret