40d9f3eed5
The information is available in the directory key block. Providing it to the user as soon as opendir() is done can save them costly code.
156 lines
3.5 KiB
ArmAsm
156 lines
3.5 KiB
ArmAsm
;
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; Colin Leroy-Mira <colin@colino.net>, 2024
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;
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; DIR* __fastcall__ opendir (register const char* name)
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;
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.export _opendir
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.import _open, _read, _close
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.import _malloc, _free
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.import ___directerrno
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.import ___oserror, __cwd
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.import pushptr1, popptr1
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.import pushax, pusha0
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.importzp ptr1
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.include "apple2.inc"
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.include "dir.inc"
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.include "errno.inc"
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.include "fcntl.inc"
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.include "zeropage.inc"
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.proc _opendir
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sta ptr1
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stx ptr1+1
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ldy #$00
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lda (ptr1),y
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cmp #'.'
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bne :+
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lda #<__cwd
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ldx #>__cwd
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sta ptr1
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stx ptr1+1
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: ; open directory
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jsr pushptr1
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lda #O_RDONLY
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jsr pusha0
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ldy #$04
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jsr _open
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cmp #$FF ; Did we succeed?
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beq @return_null
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pha ; Yes - Push fd for backup
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; malloc the dir struct
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lda #<.sizeof(DIR)
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ldx #>.sizeof(DIR)
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jsr _malloc
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bne :+
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; We failed to allocate
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pla ; Get fd back
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ldx #$00
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jsr _close ; close it
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lda #ENOMEM ; Set error
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jsr ___directerrno
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@return_null:
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lda #$00
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tax
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rts
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: ; Store dir struct to pointer
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sta ptr1
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stx ptr1+1
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; Push ptr1, read will destroy it
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jsr pushptr1
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; Save fd to dir struct
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lda #$00
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ldy #DIR::FD + 1
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sta (ptr1),y
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dey
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pla ; Get fd back
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sta (ptr1),y
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jsr pusha0 ; push fd for read
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lda #<DIR::BYTES
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clc
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adc ptr1
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pha
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lda #>DIR::BYTES
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adc ptr1+1
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tax
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pla
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jsr pushax ; Push dir->block.bytes for read
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lda #<.sizeof(DIR::BYTES)
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ldx #>.sizeof(DIR::BYTES)
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jsr _read ; Read directory block
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cpx #>.sizeof(DIR::BYTES)
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bne @err_read
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cmp #<.sizeof(DIR::BYTES)
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beq @read_ok
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@err_read:
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; Read failed, exit
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lda ___oserror
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bne :+
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lda #EINVAL
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jsr ___directerrno
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: ; Close fd
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jsr popptr1 ; Restore our dir pointer
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ldy #$00
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lda (ptr1),y ; Get fd
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ldx #$00
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jsr _close
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; Free dir structure
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lda ptr1
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ldx ptr1+1
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jsr _free
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jmp @return_null
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@read_ok:
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; Read succeeded, populate dir struct
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jsr popptr1 ; Restore our dir pointer
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; Get file_count to entry_length from block
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ldy #$26 + DIR::BYTES
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: lda (ptr1),y
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pha
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dey
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cpy #$23 + DIR::BYTES - 1
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bne :-
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; Set entry_length to file_count in struct
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ldy #DIR::ENTRY_LENGTH
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: pla
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sta (ptr1),y
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iny
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cpy #DIR::CURRENT_ENTRY
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bne :-
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; Skip directory header entry
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lda #$01
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sta (ptr1),y
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; Return pointer to dir struct
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lda ptr1
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ldx ptr1+1
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rts
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.endproc
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