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page 255
.z80
;
; FIFO channels for communication with stm32
;
global f.init,f.in,f.out,f.i.st
extrn buf.init
include config.inc
include z180reg.inc
;--------------------------------------------------------------
dseg
mkbuf ci.fifo_id, rx.buf,rx.buf_len
mkbuf co.fifo_id, tx.buf,tx.buf_len
;--------------------------------------------------------------
cseg
; Init Serial I/O for console input and output
;
f.init:
ld ix,rx.buf
ld a,rx.buf.mask
call buf.init
ld ix,tx.buf
ld a,tx.buf.mask
jp buf.init
f.i.st:
push ix
ld ix,rx.buf ;
buf.empty:
ld a,(ix+o.in_idx) ;
sub (ix+o.out_idx) ;
pop ix
ret z
or 0ffh
ret
f.in:
push ix
ld ix,rx.buf ;
buf.get:
ld a,(ix+o.out_idx) ;
bg.wait:
cp (ix+o.in_idx) ;
jr z,bg.wait
push hl ;
push ix
pop hl
add a,l
ld l,a
jr nc,bg.nc
inc h
bg.nc:
ld l,(hl)
ld a,(ix+o.out_idx) ;
inc a
and (ix+o.mask)
ld (ix+o.out_idx),a
ld a,l
pop hl
pop ix
ret
f.o.st:
push ix
ld ix,tx.buf ;
buf.full:
ld a,(ix+o.in_idx) ;
inc a
and (ix+o.mask)
sub (ix+o.out_idx) ;
pop ix
ret z
or 0ffh
ret
f.out:
push ix
ld ix,tx.buf ;
buf.put:
push hl ;
push bc
push ix
pop hl
ld c,(ix+o.in_idx) ;
ld b,0
add hl,bc
ld b,a
ld a,c ;
inc a
and (ix+o.mask)
bp.wait:
cp (ix+o.out_idx) ;
jr z,bp.wait
ld (hl),b
ld (ix+o.in_idx),a
ld a,b
pop bc
pop hl
pop ix
ret
end
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