470 lines
7.7 KiB
Z80 Assembly
470 lines
7.7 KiB
Z80 Assembly
.global _start
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_start:
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call find_disk
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/* ld hl, test_string */
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/* call print */
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call get_free_frame ; Set up a frame to load programs into at 0x8000
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ld b, c
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ld e, l
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ld d, h
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ld c, 8
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bp_call_sf:
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call set_frame
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ld iy, vfs_name ; Load and run the initrd driver
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call run_file
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vfs_loaded:
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call yield ; Yield to let the initrd driver initialize
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vfs_returned:
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ld iy, initrd_driver_name ; Load and run the initrd driver
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call run_file
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initrd_driver_loaded:
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call yield ; Yield to let the initrd driver initialize
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initrd_driver_returned:
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ld iy, initrd_fs_name ; Load and run the initrd fs driver
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call run_file
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initrd_fs_loaded:
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fs_init_wait_loop:
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call yield ; Yield to let the initrd driver initialize
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yield_done:
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call get_free_mailbox ; Initialize a mailbox
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ld (mailbox_num), hl
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ld de, 1
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call proc_map_get
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ld a, l
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cp 0
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jp z, fs_init_wait_loop
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fs_ready:
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call get_free_frame ; Set up a message frame at 0xA000
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ld a, c
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ld (msg_phys_addr), a
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ld (msg_phys_addr+1), hl
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ld b, c
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push hl
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pop de
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ld c, 0xA
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call set_frame
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frame_done:
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; Set up a register FS message to the VFS for "a" at mailbox 1
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ld hl, (mailbox_num)
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ld (0xA000), hl
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ld a, 0x0 ; Register FS operation
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ld (0xA002), a
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ld a, 0x61 ; 'a'
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ld (0xA003), a
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ld a, 0x0 ; '\0'
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ld (0xA004), a
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ld a, 0x1
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ld (0xA011), a
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ld a, 0x0
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ld (0xA012), a
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push de
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push bc
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ld de, 2 ; Get the mailbox number for the VFS
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call proc_map_get
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pmg_done:
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pop bc
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pop de
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ld c, b ; Send the message
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ld ix, 0x0000
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call mb_send
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loop:
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call yield
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loop_yield_done:
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ld hl, (mailbox_num)
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call mb_read ; Read a message
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mb_read_done:
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ld a, b ; Loop if there is no message
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cp 0
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jp nz, loop
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ld a, (0xA001)
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ld c, a
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register_done:
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; Set up a mount message to the VFS for "" on "/" with fs "a" at mailbox 1
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ld hl, (mailbox_num)
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ld (0xA000), hl
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ld a, 0x1 ; Mount operation
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ld (0xA002), a
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ld a, 0x2F ; '/'
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ld (0xA003), a
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ld a, 0x0 ; '\0'
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ld (0xA004), a
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ld a, 0x0 ; '\0'
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ld (0xA0FF), a
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ld a, 0x61 ; 'a'
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ld (0xA1FF), a
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ld a, 0x0 ; '\0'
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ld (0xA200), a
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push de
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push bc
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ld de, 2 ; Get the mailbox number for the VFS
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call proc_map_get
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mount_pmg_done:
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pop bc
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pop de
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ld c, b ; Send the message
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ld ix, 0x0000
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call mb_send
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mount_loop:
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call yield
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mount_loop_yield_done:
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ld hl, (mailbox_num)
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call mb_read ; Read a message
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mount_mb_read_done:
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ld a, b ; Loop if there is no message
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cp 0
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jp nz, loop
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ld a, (0xA001)
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ld c, a
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mount_done:
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; Set up an open message to the initrd FS for "init.elf"
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; ld hl, (mailbox_num)
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; ld (0xA000), hl
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; ld a, 0x0 ; Open operation
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; ld (0xA002), a
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; ld a, 0x69 ; i
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; ld (0xA003), a
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; ld a, 0x6e ; n
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; ld (0xA004), a
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; ld a, 0x69 ; i
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; ld (0xA005), a
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; ld a, 0x74 ; t
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; ld (0xA006), a
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; ld a, 0x2e ; .
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; ld (0xA007), a
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; ld a, 0x65 ; e
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; ld (0xA008), a
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; ld a, 0x6c ; l
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; ld (0xA009), a
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; ld a, 0x66 ; f
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; ld (0xA00a), a
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; ld a, 0x0 ; NUL
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; ld (0xA00b), a
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; push de
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; push bc
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; ld de, 1 ; Get the mailbox number for the initrd driver
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; call proc_map_get
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; pmg_done:
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; pop bc
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; pop de
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; ld c, b ; Send the message
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; ld ix, 0x0000
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; call mb_send
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; loop:
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; call yield
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; loop_yield_done:
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; ld hl, (mailbox_num)
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; call mb_read ; Read a message
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; mb_read_done:
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; ld a, b ; Loop if there is no message
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; cp 0
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; jp nz, loop
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; ld a, (0xA001)
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; ld c, a
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; open_done:
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; ; Set up a read message to the initrd FS for init.elf starting at 0x10 and reading 0x50 bytes
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; ld hl, (mailbox_num)
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; ld (0xA000), hl
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; ld a, 0x1 ; Read operation
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; ld (0xA002), a
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; ld a, c ; FD
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; ld (0xA003), a
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; ld hl, 0x10
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; ld (0xA004), hl ; File offset
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; ld hl, 0x50
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; ld (0xA006), hl ; Read length
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; ld de, 1 ; Get the mailbox number for the initrd driver
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; call proc_map_get
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; read_pmg_done:
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; ld a, (msg_phys_addr)
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; ld c, a
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; ld de, (msg_phys_addr+1)
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; ld ix, 0x0000
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; call mb_send
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; read_loop:
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; call yield
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; read_loop_yield_done:
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; ld hl, (mailbox_num)
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; call mb_read ; Read a message
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; read_mb_read_done:
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; ld a, b ; Loop if there is no message
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; cp 0
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; jp nz, read_loop
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halt
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mailbox_num: .ds.b 2
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msg_phys_addr: .ds.b 3
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vfs_name: .asciz "vfs.elf"
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initrd_driver_name: .asciz "initrd_driver.elf"
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initrd_fs_name: .asciz "initrd_fs.elf"
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; Loads and starts the ELF file with the name pointed to by IY
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run_file:
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call read_file
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ld hl, 0x8000
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push hl
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pop iy
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ld l, (iy+0x1C) ; Load IX with the start of the program headers in memory
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ld h, (iy+0x1D) ; Load IX with the start of the program headers in memory
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push hl
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pop ix
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push iy
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pop bc
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add ix, bc
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ld a, (iy+0x2C) ; load B with the number of program headers
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ld b, a
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phead_loop:
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ld a, (ix+0)
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cp 1
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jp NZ, next_seg
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push bc
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ld c, (ix+20)
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ld b, (ix+21)
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; b = if c > 0 || b & 0xF > 0 {
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; (b & 0xF0) + 0x10
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; } else {
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; b & 0xF0
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; } >> 4
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ld a, c
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cp 0
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jp z, cmp2
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jp blk1
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cmp2:
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ld a, b
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and 0xF
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cp 0
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jp z, blk2
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blk1:
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ld a, b
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and 0xF0
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add a, 0x10
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ld b, a
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jp end1
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blk2:
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ld a, b
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and 0xF0
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ld b, a
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end1:
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srl b
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srl b
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srl b
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srl b
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ld c, (ix+9)
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srl c
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srl c
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srl c
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srl c
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push iy
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push ix
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push de
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ld a, c
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sla a
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add a, c
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ld c, a
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ld b, 0
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map_seg_frame:
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ld ix, proc_pagemap
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add ix, bc
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push ix
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ld a, 1
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call 0xdffd
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pop ix
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seg_frame_found:
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ld (ix+0), c
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ld (ix+1), l
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ld (ix+2), h
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ld b, c
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ld e, l
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ld d, h
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ld c, 7
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call set_frame
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/* ld b, c */
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/* ld d, h */
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/* ld e, l */
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/* pop hl */
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/* ld c, l */
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/* push hl */
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/* call set_frame */
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/* pop bc */
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/* inc c */
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/* djnz page_alloc_loop */
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pop de
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pop ix
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pop iy
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seg_load:
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;Zero out the segments place in memory
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ld c, (ix+20) ; Load the byte counter with the number of bytes to zero out
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ld b, (ix+21)
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ld e, (ix+8) ; Load the destination & source address register with the destination location of the segment in memory
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ld d, (ix+9)
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ld a, d
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and 0xF
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or 0x70
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ld d, a
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ld h, d
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ld l, e
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ld (hl), 0 ; Zero out the first byte in the segment ( Acts as a 'seed' for the zeroing )
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ldir
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ld c, (ix+16) ; Load the byte counter with the number of bytes to transfer
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ld b, (ix+17)
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ld l, (ix+4) ; Load the source address register with the memory address if the segment data
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ld h, (ix+5)
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push iy
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pop de
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add hl, de
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ld e, (ix+8) ; Load the destination & source address register with the destination location of the segment in memory
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ld d, (ix+9)
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ld a, d
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and 0xF
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or 0x70
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ld d, a
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ldir; Do the transfer
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pop bc
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next_seg:
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ld de, 32
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add ix, de
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dec b
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ld a, b
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jp nz, phead_loop
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ld l, (iy+0x18) ; Load HL with the program entry point
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ld h, (iy+0x19) ; Load HL with the program entry point
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ld iy, proc_pagemap
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call new_process
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ret
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proc_pagemap:
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.ds.b 36
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strcmp:
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strcmp_loop:
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ld a, (ix+0)
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ld b, (iy+0)
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cp b
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jp nz, strcmp_different
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cp 0
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ret z
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inc ix
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inc iy
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jp strcmp_loop
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strcmp_different:
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ld a, 1
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ret
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; Reads a file off the disk to 0x8000 in memory
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; Pointer to file name in iy
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read_file:
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ld c, 0
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ld de, 1
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ri_find_loop:
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ld hl, 0x8000
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push bc
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call read_sector
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ri_find_read_done:
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ld ix, 0x8001
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push iy
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call strcmp
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pop iy
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pop bc
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jp z, ri_init_found
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push bc
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ld b, 0
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ld a, (0x8000)
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ld c, a
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ld hl, 0x8004
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add hl, bc
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ld c, (hl)
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inc hl
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ld b, (hl)
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ld l, c
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ld h, b
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inc hl
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add hl, de
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ld e, l
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ld d, h
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pop bc
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ld a, c
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adc a, 0
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ld c, a
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jp ri_find_loop
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ri_init_found:
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push bc
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ld b, 0
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ld a, (0x8000)
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ld c, a
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ld hl, 0x8004
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add hl, bc
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pop bc
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ld b, (hl)
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ld hl, 1
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add hl, de
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ld e, l
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ld d, h
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ld a, c
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adc a, 0
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ld c, a
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ld hl, 0x8000
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ri_read_loop:
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push bc
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call read_sector
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pop bc
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push hl
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ld hl, 1
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add hl, de
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ld e, l
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ld d, h
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ld a, c
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adc a, 0
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ld c, a
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pop hl
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djnz ri_read_loop
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ret
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; Given a sector number in C:DE and a buffer address in HL, reads the sector off disk.
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read_sector:
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push bc
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ld c,0xFF ; Force the top half of the IO address to be the id of the card,
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ld a, (disk_num) ; so the block transfer instructions can be used
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out (c), a
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pop bc
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ld a, c
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ld c, 0
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out (c), e
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inc c
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out (c), d
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inc c
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out (c), a
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ld b, 0x0 ; Setup a transfer of 256 bytes (1 sector) at a time
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ld c, 0x3 ; from the storage device's data port
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inir
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ld c,0xFF ; Unforce the top half of the IO address
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in a,(c)
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ret
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.global find_disk
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; Clobbers A and HL
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find_disk:
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ld b,0x4
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ld a, 10
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call 0xdffd
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ld a, l
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ld (disk_num), a
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ret
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disk_num: .ds.b 1
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/* initrd: */
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/* .incbin "initrd" */
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/* initrd_end: */
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