move fdtoiocb function into its own file -- idea by Daniel Serpell

[cc65] / libsrc / atari / fdtable.s

diff --git a/libsrc/atari/fdtable.s b/libsrc/atari/fdtable.s
index 5a8063c38f6a685d10fa0867b7913dd8fdaadf7d..111f340d0e064e6011ef4f21ee92fae92345eea0 100644 (file)
--- a/libsrc/atari/fdtable.s
+++ b/libsrc/atari/fdtable.s
@@ -10,7 +10,6 @@
        .import fd_table,fd_index
        .import fdt_to_fdi
        .export clriocb
-       .export fdtoiocb
        .export fdtoiocb_down
        .export findfreeiocb
        .export fddecusage
@@ -42,7 +41,7 @@
        cmp     fd_table+ft_iocb,x      ; entry in use?
        beq     inval                   ; no, return error
        lda     fd_table+ft_usa,x       ; get usage counter
-       beq     ok_notlast              ; 0?
+       beq     ok_notlast              ; 0? (shouldn't happen)
        sec
        sbc     #1                      ; decr usage counter
        sta     fd_table+ft_usa,x
@@ -53,10 +52,11 @@ retiocb:php
        tax
        plp
        bne     cont
-       php
        lda     #$ff
        sta     fd_table+ft_iocb,y      ; clear table entry
-       plp
+       lda     fd_table+ft_flag,y
+       and     #16                     ; opened by app?
+       eor     #16                     ; return set Z if yes
 cont:  rts
 
 ok_notlast:
@@ -87,31 +87,6 @@ loop:        sta     ICHID,x
 .endproc
 
 
-; gets fd in ax
-; return iocb index in X
-; return N bit set for invalid fd
-; all registers destroyed
-.proc  fdtoiocb
-
-       cpx     #0
-       bne     inval
-       cmp     #MAX_FD_INDEX
-       bcs     inval
-       tax
-       lda     fd_index,x
-       asl     a                       ; create index into fd table
-       asl     a
-       tax
-       lda     #$ff
-       cmp     fd_table+ft_iocb,x      ; entry in use?
-       beq     inval                   ; no, return error
-       lda     fd_table+ft_usa,x       ; get usage counter
-       beq     inval                   ; 0? should not happen
-       lda     fd_table+ft_iocb,x      ; get iocb
-       rts
-
-.endproc       ; fdtoiocb
-
 ; find a free iocb
 ; no entry parameters
 ; return ZF = 0/1 for not found/found
@@ -136,6 +111,7 @@ found:      rts
 
 .endproc       ; findfreeiocb
 
+
 ; decrements usage counter for fd
 ; if 0 reached, it's marked as unused
 ; get fd index in tmp2
@@ -169,6 +145,7 @@ ret:        rts
 
 .endproc       ; fddecusage
 
+
 ; newfd
 ;
 ; called from open() function
@@ -187,13 +164,9 @@ ret:       rts
 ;      C    - 0/1 for no open needed/open should be performed
 ; all registers preserved!
 
-; local variables:
-;   AX     - 0 (A-0,X-1)
-;   Y      - 2
-;   ptr4   - 3,4  (backup)
-;   devnum - 5
-
        .bss
+
+; local variables:
 loc_Y:         .res    1
 loc_ptr4_l:    .res    1
 loc_ptr4_h:    .res    1
@@ -251,7 +224,7 @@ do_open:lda tmp1
        ldy     #$ff
 srchfree:
        tya
-       cmp     fd_table,x
+       cmp     fd_table,x      ; check ft_iocb field for $ff
        beq     freefnd         ; found a free slot
        txa
        clc
@@ -289,11 +262,12 @@ l2:       sta     fd_table+ft_dev,x       ; set device
        lda     loc_Y
        sta     fd_table+ft_iocb,x      ; set iocb index
        lda     loc_devnum
-       and     #7                      ; only 3 bits
+       and     #7                      ; device number is 3 bits
+       ora     #16                     ; indicated a fd actively opened by the app
        sta     fd_table+ft_flag,x
        lda     tmp2
        jsr     fdt_to_fdi              ; get new index
-       bcs     noslot                  ; no one available
+noslot1:bcs    noslot                  ; no one available (noslot1: helper label for branch out of range)
        ;cmp    #$ff                    ; no one available
        ;beq    noslot  ;@@@ cleanup needed
        sta     tmp2                    ; return index
@@ -338,9 +312,6 @@ srch2:      txa
 ; not found, open new iocb
        jmp     do_open
 
-; helper for branch out of range
-noslot1:jmp    noslot
-
 ; found device in table, check device number (e.g R0 - R3)
 fnddev:        lda     fd_table+ft_flag,x
        and     #7