insertbyte
;ahl=insert addr
;c=symbol
;out: ahl=next addr (kills bc,de)
push af
push hl
push bc ;c=symbol
push af
push hl
call incfilesize ;before! because we can access new page
call setchanged
pop hl
pop af
pop de ;e=symbol
insertbyte_pg0
;ahl=addr
;e=symbol
push af
push hl
call ahl_to_pgaddr_pgsizeafter ;hl=phys addr, bc=block size after hl (may be 0!) (keeps de)
push bc
call insertbyte_ldirbc
pop bc
pop hl
pop af
add hl,bc
adc a,0
;ahl=addr for next block
;e=symbol for next block (out-of-text for eof)
call iseof
jr nz,insertbyte_pg0
pop hl
pop af ;insert addr
nextbyte
ld bc,1
add hl,bc
adc a,b;0
ret
deletebyte
;ahl=delete addr (kept) (kills bc,de)
push af
push hl
deletebyte_pg0
;ahl=addr
push af
push hl
call ahl_to_pgaddr_pgsizeafter ;hl=phys addr, bc=block size after hl (may be 0!) (keeps de)
call setchanged
;hl=byte addr to delete
;bc=size from hl to end
push bc
call deletebyte_ldirbc
pop bc
pop hl
pop af
add hl,bc
adc a,0
;ahl=addr for next block
call iseof
jr z,deletebyte_pgq
;copy first byte of next block to last byte of this block
push af
push hl
call ahl_to_pgaddr;_pgsizeafter ;hl=phys addr, bc=block size after hl (may be 0!) (keeps de)
ld e,(hl) ;first byte of next block
pop hl
pop af
push af
push hl
dec hl ;last byte of this block
call ahl_to_pgaddr;_pgsizeafter ;hl=phys addr, bc=block size after hl (may be 0!) (keeps de)
ld (hl),e
pop hl
pop af
jr deletebyte_pg0
deletebyte_pgq
call decfilesize ;after! because we can access deleted last page
pop hl
pop af ;delete addr
ret
deletebyte_ldirbc
;hl=byte addr to delete
;bc=size from hl to end (may be 0!)
dec bc ;bc=size from ahl+1 to end
ld a,b
or c
ret z
ld d,h
ld e,l
inc hl
ld a,b
or c
ret z ;jr z,$+4
ldir
ret
;reserves page
incfilesize
;ld hl,(fcb+FCB_FSIZE)
call getsize
push af
push hl
ld a,h
and 0x3f
or l
call z,reservepage
pop hl
pop af
ld bc,1
add hl,bc
adc a,b;0
ld (filesize),hl
ld (filesizeHSW),a
ret
;unreserves page
decfilesize
;ld hl,(fcb+FCB_FSIZE)
call getsize
or a
ld bc,1
sbc hl,bc
sbc a,b;0
ld (filesize),hl
ld (filesizeHSW),a
ld a,h
and 0x3f
or l
call z,unreservepage
ret
ahl_to_pgaddr_pgsizeafter
;ahl=addr
;out: hl=phys addr, bc=block size after hl (may be 0!) (keeps de)
push af
push hl
ld l,h
ld h,a
add hl,hl
add hl,hl
push hl ;h=page number
call getsize
ld c,h
rl c
rla
rl c
rla
ld c,a ;c=end page number
pop af ;page number
cp c
ld bc,0x4000
jr nz,ahl_to_pgaddr_pgsize_noend
;size=hl&0x3fff
;add hl,hl
;add hl,hl
;srl h
;srl h
ld a,h
and 0x3f
ld b,a
ld c,l
ahl_to_pgaddr_pgsize_noend
;bc=pg size (may be 0!)
pop hl
pop af
call ahl_to_pgaddr ;hl=phys addr (keeps bc)
push hl
res 7,h
;res 6,h
ld a,c
sub l
ld c,a
ld a,b
sbc a,h
ld b,a ;bc=block size after hl (may be 0!)
pop hl
ret
insertbyte_ldirbc
;e=byte to insert
;hl=byte addr to insert
;bc=size from hl to end (may be 0!)
;out: e=deleted last byte, [hl=end addr]
ld a,b
or c
ret z
ld a,e
add hl,bc ;end addr
dec hl
ld e,(hl)
push de ;d=deleted last byte
ld d,h
ld e,l
inc de
;push de ;end addr
dec hl
dec de
push af
dec bc
ld a,b
or c
jr z,$+4
lddr
pop af
;pop hl ;end addr
ld (de),a
pop de ;e=deleted last byte
ret
prevbyte
ld bc,1
or a
sbc hl,bc
sbc a,b;0
ret
getbyte
push af
push hl
call ahl_to_pgaddr
ld c,(hl)
pop hl
pop af
ret
pgaddr_to_ahl
;de = new addr (bits 13..0), bit 14 = overflow
;ahl = old addr
bit 6,d
ld bc,0x4000
jr z,$+4
add hl,bc
adc a,c;0
ld c,a
ld l,e
ld a,d
xor h
and 0x3f
xor h
ld h,a ;bits 13..0 copied
ld a,c ;ahl = new addr
ret ;nc
reservepage
;new page, set page in textpages, npages++, set page in #c000
;nz=error
OS_NEWPAGE
or a
ret nz
npages=$+1
ld hl,textpages
ld (hl),e
inc l
ld (npages),hl
ld a,e
SETPG32KHIGH
xor a
ret ;z
unreservepages
unreservepages0
call unreservepage
jr z,unreservepages0
ret
unreservepage
;del page, npages--
;nz=error
ld hl,(npages)
ld a,l
or a
jr z,unreservepage_fail
dec l
ld (npages),hl
ld e,(hl)
OS_DELPAGE
xor a
ret ;z
unreservepage_fail
xor a
dec a
ret ;nz
ahl_to_pgaddr
;keeps bc,de
;counts physical hl
rl h
rla
rl h
rla
srl h
scf
rr h
push bc
call setpg32k
pop bc
ret
setpg32k
;a=page number in table (0..)
push hl
ld l,a
ld h,textpages/256
ld a,(hl)
SETPG32KLOW
inc l
ld a,(hl)
SETPG32KHIGH
pop hl
ret
align 256
textpages
ds 256