XOPEN

Description

open a file

Input

• Y : flag open mode
• A&X : path filename

Output

• AX contains $FF if it does not exists
• A : FD id if file is found

Modify

• RES, A X Y, XOPEN_SAVE XOPEN_FLAGS, XOPEN_RES_SAVE, XOPEN_SAVEA
• with XMALLOC call TR7

Internal kernel calls

• XMALLOC
• create_file_pointer

Changelog

Since kernel 2022.2

Flag | File exists | behaviour O_WRONLY | No | return Null O_WRONLY | Yes | open and return FD O_RDONLY | Yes | open and return FD O_WRONLY | No | return Null O_CREAT | No | Create file and open and return FD O_CREAT | Yes | open and return FD

Usage

    lda #<str
    ldx #>str
    ldy #O_CREAT

    BRK_TELEMON XOPEN
    rts
str:
    .asciiz "myfile"

See fopen macro from orix-sdk to use it

XOPEN does not manage './' or '../' calls

Multiples opened files are working since kernel 2022.2

Max 2 opened files are working since kernel 2022.2, it's a constant defined in kernel build

Flags behaviors since kernel 2023.1

Flag	File exists	Behaviour
O_WRONLY & O_CREAT	No	Create file, open and return FD
O_WRONLY	No	return Null (Changed since kernel 2023.1)
O_WRONLY	Yes	open and return FD
O_RDONLY	Yes	open and return FD
O_WRONLY	No	return Null
O_CREAT	No	Create file and open and return FD
O_CREAT	Yes	open and return FD

Flags behaviors before kernel 2023.1

Flag	File exists	Behaviour
O_WRONLY & O_CREAT	No	Create file, open and return FD
O_WRONLY	No	open and return FD
O_WRONLY	Yes	open and return FD
O_RDONLY	Yes	open and return FD
O_WRONLY	No	return Null
O_CREAT	No	Create file and open and return FD
O_CREAT	Yes	open and return FD