.global libvfs_init
; Pointer to message frame in HL
; Physical address of message frame in C:DE
; Clobbers A, BC, DE, HL, IX
libvfs_init:
ld (msg_frame_ptr), hl
ld a, c
ld (msg_frame_phys), a
ld (msg_frame_phys+1), de
call get_free_mailbox ; Initialize a mailbox
ld (mailbox_num), hl
ret

.global libvfs_register_fs
; Registers a FS with the VFS
; Mailbox in HL, pointer to name in IX
; Clobbers A, BC, DE, HL, IX, IY
libvfs_register_fs:
push hl
ld iy, (msg_frame_ptr)
ld hl, (mailbox_num)
ld (iy), l
ld (iy+1), h
ld a, 0x0 ; Register FS operation
ld (iy+2), a
ld bc, 7
push ix
pop hl
ld d, iyh 
ld e, 0x3
call strcpy
pop hl
ld (iy+0x11), l
ld (iy+0x12), h
ld de, 2 ; Get the mailbox number for the VFS
call proc_map_get
pmg_done:
ld a, (msg_frame_phys)
ld c, a
ld de, (msg_frame_phys+1)
ld ix, 0x0000
call mb_send
reg_fs_loop:
call yield
loop_yield_done:
ld hl, (mailbox_num)
call mb_read ; Read a message
reg_fs_mb_read_done:
ld a, b ; Loop if there is no message
cp 0
jp nz, reg_fs_loop
ret

.global libvfs_mount
; Mounts a FS
; Device string in BC
; Path string in DE
; FS name string in HL
; Clobbers A, BC, DE, HL, IX, IY
libvfs_mount:
push hl
push bc
push de
ld iy, (msg_frame_ptr)
ld hl, (mailbox_num)
ld (iy), l
ld (iy+1), h
ld a, 0x1 ; Mount operation
ld (iy+2), a
ld d, iyh
ld e, 0x3
pop hl
call strcpy
ld d, iyh
ld e, 0xFF
pop hl
call strcpy
ld d, iyh
inc d
ld e, 0xFF
pop hl
call strcpy
ld de, 2 ; Get the mailbox number for the VFS
call proc_map_get
mount_pmg_done:
; Send the message
ld a, (msg_frame_phys)
ld c, a
ld de, (msg_frame_phys+1)
ld ix, 0x0000
call mb_send
mount_loop:
call yield
mount_loop_yield_done:
ld hl, (mailbox_num)
call mb_read ; Read a message
mount_mb_read_done:
ld a, b ; Loop if there is no message
cp 0
jp nz, mount_loop
mount_done:
ret

.global libvfs_open
; Opens a file
; Path in HL 
; Pointer to 4-byte buffer in DE (file info saved there)
; FD returned in DE, MBID of FS in HL
; Clobbers A, BC, DE, HL, IX, IY
libvfs_open:
push de
push hl
ld iy, (msg_frame_ptr)
ld hl, (mailbox_num)
ld (iy), l
ld (iy+1), h
ld a, 0x2 ; Open operation
ld (iy+2), a
ld d, iyh
ld e, 0x3
pop hl
call strcpy
ld de, 2 ; Get the mailbox number for the VFS
call proc_map_get
open_pmg_done:
; Send the message
ld a, (msg_frame_phys)
ld c, a
ld de, (msg_frame_phys+1)
ld ix, 0x0000
call mb_send
open_loop:
call yield
open_loop_yield_done:
ld hl, (mailbox_num)
call mb_read ; Read a message
open_mb_read_done:
ld a, b ; Loop if there is no message
cp 0
jp nz, open_loop
open_done:
ld hl, (msg_frame_ptr)
pop de
ld bc, 4
ldir
ret

.global libvfs_read
; Reads data from an open file
; Pointer to file struct in HL
; Data length in BC
; Offset in DE
; Buffer returned in HL
; BUFFER INVALIDATED WHEN MESSAGE IS NEXT SENT 
; WITH FRAME GIVEN ON INIT
libvfs_read:
push hl
ld iy, (msg_frame_ptr)
ld hl, (mailbox_num)
ld (iy), l
ld (iy+1), h
pop hl
ld a, 0x1 ; Read operation
ld (iy+2), a
ld a, (hl)
ld (iy+3), c
inc hl
ld a, (hl)
ld (iy+4), b
inc hl
ld (iy+5), e
ld (iy+6), d
ld (iy+7), c
ld (iy+8), b
; Send the message
ld c, (hl)
inc hl
ld b, (hl)
push bc
pop hl
ld a, (msg_frame_phys)
ld c, a
ld de, (msg_frame_phys+1)
ld ix, 0x0000
call mb_send
read_loop:
call yield
read_loop_yield_done:
ld hl, (mailbox_num)
call mb_read ; Read a message
read_mb_read_done:
ld a, b ; Loop if there is no message
cp 0
jp nz, read_loop
read_done:
ld hl, (msg_frame_ptr)
ret

.bss
mailbox_num: .ds.b 2
msg_frame_ptr: .ds.b 2
msg_frame_phys: .ds.b 3