1
0
mirror of https://github.com/cc65/cc65.git synced 2025-01-10 03:30:05 +00:00
cc65/libsrc/apple2/opendir.s
2024-11-17 11:03:58 +01:00

160 lines
3.6 KiB
ArmAsm

;
; Colin Leroy-Mira <colin@colino.net>, 2024
;
; DIR* __fastcall__ opendir (register const char* name)
;
.export _opendir, read_dir_block_ptr1
.import closedir_ptr1
.import _open, _read, _close
.import _malloc
.import ___directerrno
.import ___oserror, __cwd
.import pushptr1, popptr1
.import pushax, pusha0
.import return0, returnFFFF
.importzp ptr1
.include "apple2.inc"
.include "dir.inc"
.include "errno.inc"
.include "fcntl.inc"
.include "zeropage.inc"
.proc _opendir
sta ptr1
stx ptr1+1
ldy #$00
lda (ptr1),y
cmp #'.'
bne :+
lda #<__cwd
ldx #>__cwd
sta ptr1
stx ptr1+1
: ; Open directory
jsr pushptr1
lda #O_RDONLY
jsr pusha0
ldy #$04
jsr _open
cmp #$FF ; Did we succeed?
beq @return_null
pha ; Yes - Push fd for backup
; malloc the dir struct
lda #<.sizeof(DIR)
ldx #>.sizeof(DIR)
jsr _malloc
bne :+
; We failed to allocate
pla ; Get fd back
ldx #$00
jsr _close ; Close it
lda #ENOMEM ; Set error
jsr ___directerrno
@return_null:
jmp return0
: ; Store dir struct to pointer
sta ptr1
stx ptr1+1
; Save fd to dir struct
lda #$00
ldy #DIR::FD + 1
sta (ptr1),y
dey
pla ; Get fd back
sta (ptr1),y
jsr read_dir_block_ptr1
bcc @read_ok
; Close directory, free it
jsr closedir_ptr1
jmp return0 ; Return NULL
@read_ok:
; Read succeeded, populate dir struct
; Get file_count to entry_length from block
ldy #$26 + DIR::BYTES
: lda (ptr1),y
pha
dey
cpy #$23 + DIR::BYTES - 1
bne :-
; Set entry_length to file_count in struct
ldy #DIR::ENTRY_LENGTH
: pla
sta (ptr1),y
iny
cpy #DIR::CURRENT_ENTRY
bne :-
; Skip directory header entry
lda #$01
sta (ptr1),y
; Return pointer to dir struct
lda ptr1
ldx ptr1+1
rts
.endproc
; Read a directory for the DIR* pointer in ptr1
; Return with carry clear on success
read_dir_block_ptr1:
; Push ptr1, read will destroy it
jsr pushptr1
ldy #DIR::FD
lda (ptr1),y
jsr pusha0 ; Push fd for read
lda #<DIR::BYTES
clc
adc ptr1
pha
lda #>DIR::BYTES
adc ptr1+1
tax
pla
jsr pushax ; Push dir->block.bytes for read
lda #<.sizeof(DIR::BYTES)
ldx #>.sizeof(DIR::BYTES)
jsr _read ; Read directory block
cpx #>.sizeof(DIR::BYTES)
bne @read_err
cmp #<.sizeof(DIR::BYTES)
beq @read_ok
@read_err:
; Read failed, exit
lda ___oserror
bne :+
lda #EINVAL
jsr ___directerrno
: sec
bcs @out
@read_ok:
clc
@out:
jmp popptr1