mirror of
https://github.com/cc65/cc65.git
synced 2024-12-27 15:29:46 +00:00
85 lines
1.4 KiB
ArmAsm
85 lines
1.4 KiB
ArmAsm
;
|
|
; Christian Groessler, Oct-2000
|
|
;
|
|
; allocates a new fd in the indirection table
|
|
; the fdtable itself is defined here
|
|
;
|
|
|
|
.include "atari.inc"
|
|
.include "fd.inc"
|
|
.importzp tmp1
|
|
|
|
.export fdt_to_fdi,getfd
|
|
.export fd_table,fd_index
|
|
.export ___fd_table,___fd_index ; for test(debug purposes only
|
|
|
|
.data
|
|
|
|
___fd_index:
|
|
fd_index: ; fd number is index into this table, entry's value specifies the fd_table entry
|
|
.res MAX_FD_INDEX,$ff
|
|
|
|
___fd_table:
|
|
fd_table: ; each entry represents an open iocb
|
|
.byte 0,0,'E',0 ; system console, app starts with opened iocb #0 for E:
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
.byte 0,$ff,0,0
|
|
|
|
.code
|
|
|
|
; fdt_to_fdi
|
|
; returns a fd_index entry pointing to the given ft_table entry
|
|
; get fd_table entry in A
|
|
; return C = 0/1 for OK/error
|
|
; return fd_index entry in A if OK
|
|
; registers destroyed
|
|
.proc fdt_to_fdi
|
|
|
|
tay
|
|
lda #$ff
|
|
tax
|
|
inx
|
|
loop: cmp fd_index,x
|
|
beq found
|
|
inx
|
|
cpx #MAX_FD_INDEX
|
|
bcc loop
|
|
rts
|
|
|
|
found: tya
|
|
sta fd_index,x
|
|
txa
|
|
clc
|
|
rts
|
|
|
|
.endproc
|
|
|
|
; getfd
|
|
; get a new fd pointing to a ft_table entry
|
|
; usage counter of ft_table entry incremented
|
|
; A - fd_table entry
|
|
; return C = 0/1 for OK/error
|
|
; returns fd in A if OK
|
|
; registers destroyed, tmp1 destroyed
|
|
.proc getfd
|
|
|
|
sta tmp1 ; save fd_table entry
|
|
jsr fdt_to_fdi
|
|
bcs error
|
|
|
|
pha
|
|
lda tmp1
|
|
asl a
|
|
asl a ; also clears C
|
|
tax
|
|
inc fd_table+ft_usa,x ; increment usage counter
|
|
pla
|
|
error: rts
|
|
|
|
.endproc
|