Commodore 1571 firmware
Relative Files
.page
.subttl 'rel1.src'
;***********************************
;*
;* routine: nxtrec
;*
;*
;*
;*
;*
;***********************************
nxtrec
lda #ovrflo
jsr clrflg
lda #lrf
jsr tstflg
bne nxtr40
ldx lindx
inc recl,x ; goto next record #
bne nxtr15
inc rech,x
nxtr15
ldx lindx
lda nr,x
beq nxtr45 ; there is a nr
jsr getpnt ; get pointer
ldx lindx ; test if same buffer
cmp nr,x
bcc nxtr20 ; yes, bt<nr
jsr nrbuf ; no,next buffer
nxtr20 ldx lindx
lda nr,x
jsr setpnt ; advance to next rec
lda (buftab,x) ; read 1st dat byte
sta data ; save for read channel
lda #ovrflo
jsr clrflg ; clear
; the overflow flag
jsr addnr ; advance nr
nxout
pha
bcc nxtr30 ; no block boundary
lda #0
jsr drdbyt ; check track link
bne nxtr30 ; not last block
pla
cmp #2
beq nxtr50
nxtr45
lda #lrf
jsr setflg
nxtr40
jsr getpre
lda buftab,x
sta lstchr,y
lda #cr
sta data
rts
nxtr50
jsr nxtr35
ldx lindx
lda #0
sta nr,x
rts
nxtr30
pla
nxtr35
ldx lindx
;*
sta nr,x
jmp setlst
;*
;*
;**********************************
;*
;*
;* nrbuf
;*
;*
;********************************
;*
;*
nrbuf ; read trk,sec link
jsr setdrn
jsr rdlnk
jsr gaflgs ; test if dirty
bvc nrbu50 ; clean, dont write out
jsr wrtout ; dirty, write out
jsr dblbuf ; toggle active buffer
lda #2
jsr setpnt
jsr tstwrt ; test if lstjob is wrt
bne nrbu20 ; not a write,buffer ok
jsr rdab ; read in needed buffer
jmp watjob ; wait around till done
nrbu50 jsr dblbuf ; toggle act buf
jsr tstwrt ; was lstjob a wrt?
bne nrbu70 ; not a write
jsr rdab ; read in needed buffer
jsr watjob ; wait till done
nrbu70 ; read trk,sec link
jsr rdlnk ; to do a read ahead
lda track ; test if last buffer
beq nrbu20 ; yes,no dbl buff todo
jsr dblbuf ; start read job on the
jsr rdab ; inactive buffer
jsr dblbuf
nrbu20 rts