From f3530d5528e07b8bd0b421a799839d0950e227fd Mon Sep 17 00:00:00 2001
From: pjht <pterpstra@pterpstra.com>
Date: Sun, 5 Nov 2023 10:34:11 -0600
Subject: [PATCH] Add open to the VFS

---
 init.z80    |  38 ++++++++++++++++++--
 test_fs.z80 |  11 ++++--
 vfs.z80     | 101 ++++++++++++++++++++++++++++++++++++++++++++++------
 3 files changed, 135 insertions(+), 15 deletions(-)

diff --git a/init.z80 b/init.z80
index 7d0ca14..c7b974e 100644
--- a/init.z80
+++ b/init.z80
@@ -74,9 +74,43 @@ mount_mb_read_done:
 ld a, b ; Loop if there is no message
 cp 0
 jp nz, mount_loop
-ld a, (0xA001)
-ld c, a
 mount_done:
+; Set up an open message to the VFS for "/test"
+ld hl, (mailbox_num)
+ld (0xA000), hl
+ld a, 0x2 ; Open operation
+ld (0xA002), a
+ld a, 0x2F ; '/'
+ld (0xA003), a
+ld a, 0x74 ; 't'
+ld (0xA004), a
+ld a, 0x65 ; 'e'
+ld (0xA005), a
+ld a, 0x73 ; 's'
+ld (0xA006), a
+ld a, 0x74 ; 't'
+ld (0xA007), a
+ld a, 0x0 ; '\0'
+ld (0xA008), a
+push de
+push bc
+ld de, 2 ; Get the mailbox number for the VFS
+call proc_map_get
+open_pmg_done:
+pop bc
+pop de
+ld ix, 0x0000 ; Send the message
+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:
 halt
 
 mailbox_num: .ds.b 2
diff --git a/test_fs.z80 b/test_fs.z80
index 8161e80..08e6656 100644
--- a/test_fs.z80
+++ b/test_fs.z80
@@ -82,13 +82,18 @@ call mb_send
 jp msg_loop
 
 open: 
-jp z, operation_done
+halt
+ld a, 0xAA
+ld (0xB000), a
+ld a, 0x55
+ld (0xB001), a
+jp operation_done
 
 read: 
-jp z, operation_done
+jp operation_done
 
 mount: 
-jp z, operation_done
+jp operation_done
 
 
 
diff --git a/vfs.z80 b/vfs.z80
index df73774..65227ba 100644
--- a/vfs.z80
+++ b/vfs.z80
@@ -114,15 +114,13 @@ mount:
 ld a, (mount_count)
 ld l, 0x0
 ld h, a
-ld de, data_mount_offset
-add hl, de
-ld de, 0x9000
+ld de, 0x9000 + data_mount_offset
 add hl, de
 push hl
 pop de
 push de
 ld hl, 0xB003
-ld bc, 252
+ld bc, 0xFC
 ldir
 ; FS type at 0xB1FF
 ld a, (fs_count)
@@ -141,21 +139,27 @@ jp mount_loop1_done
 add hl, de
 djnz mount_loop1
 mount_loop1_done:
+; hl -> pointer to fs type info
+; top of stack -> pointer to open mount info slot
 ld de, 14
 add hl, de
 pop ix
-ld de, 252
+; hl -> pointer to byte 15 of fs type info
+; ix -> pointer to open mount info slot
+ld de, 0xFD
 add ix, de
+; ix -> pointer to offset 0xFD of mount info
+; fs info word starting at 0xE -> mount info word starting at 0xFD
 ld e, (hl)
 inc hl
 ld d, (hl)
 ld (ix), e
 ld (ix+1), d
-push ix
 ld hl, (fs_mailbox_num)
 ld (0x8000), hl
 ld a, 0x2
 ld (0x8002), a
+push ix
 push de
 ld hl, 0xB0FF
 ld de, 0x8003
@@ -175,10 +179,9 @@ ld a, b ; Loop if there is no message
 cp 0
 jp nz, mount_wait_loop
 pop ix
+; response byte 1 -> mount info byte at offset 0xFF
 ld a, (0x8000)
 ld (ix+2), a
-ld a, (0x8001)
-ld (ix+3), a
 ld a, (mount_count)
 inc a
 ld (mount_count), a
@@ -192,21 +195,99 @@ ld a, (iy)
 ld b, a
 ld a, (ix)
 cp b
+jp nz, vfsstrcmp_loopend
 cp 0
 ret z
-jp nz, vfsstrcmp_loopend
 inc ix
 inc iy
 jp vfsstrcmp_loop
 vfsstrcmp_loopend:
+ld a, (ix)
+cp 0
+ret z
 ld a, (iy)
 ld b, a
 ld a, (ix)
 sub b
 ret
 
-; TODO open 
 open:
+; Scan mountpoints for largest prefix matching path
+ld hl, data_mount_offset + 0x9000
+ld bc, 0
+ld de, 0
+open_mount_scan:
+ld a, (hl)
+cp 0
+jp z, open_mount_scan_done
+push hl
+pop ix
+ld iy, 0xB003
+push bc
+call vfsstrcmp
+pop bc
+cp 0
+jp nz, open_no_prefix
+push hl
+pop de
+call strlen
+open_no_prefix:
+ld a, h
+inc a
+ld h, a
+ld l, 0
+jp open_mount_scan
+open_mount_scan_done:
+; Send open request to FS w/ path-prefix and mount ID
+ld hl, 0xB003
+add hl, bc
+push de
+; mountpoint path -> 0x8003-0x8103 (exclusive end)
+ld de, 0x8003
+ld bc, 0x100
+ldir
+pop de
+; mount info byte 0xFF -> 0x8103
+ld e, 0xFF
+ld a, (de)
+ld (0x8103), a
+; imm 0x0 -> 0x8002
+ld a, 0x0
+ld (0x8002), a
+; fs_mailbox_num (16bit) -> 0x8000,0x8001
+ld hl, 0x8000
+ld bc, (fs_mailbox_num)
+ld (hl), c
+inc hl
+ld (hl), b
+; mount info word 0xFD -> hl
+ld e, 0xFD
+ld a, (de)
+ld l, a
+inc de
+ld a, (de)
+ld h, a
+push hl
+ld a, (send_page_addr)
+ld c, a
+ld de, (send_page_addr+1)
+ld ix, 0x0
+call mb_send
+; Get request back, pass on to caller (add in alt MB id support?)
+open_wait_loop:
+call yield
+ld hl, (fs_mailbox_num)
+call mb_read ; Read a message
+ld a, b ; Loop if there is no message
+cp 0
+jp nz, open_wait_loop
+pop hl
+ld (0xB002), hl
+; word at 0x8000 -> 0xB000
+ld a, (0x8000)
+ld (0xB000), a
+ld a, (0x8001)
+ld (0xB001), a
 jp operation_done