140 lines
2.1 KiB
Z80 Assembly
140 lines
2.1 KiB
Z80 Assembly
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.global _start
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_start:
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call get_free_mailbox ; Get a mailbox
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push hl
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ld de, 1
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call get_free_frame ; Set up a frame to send messages 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, 0x8
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call set_frame
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call get_free_frame ; Set up a frame for the file mapping at 0xA000
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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, 0xA
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call set_frame
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ld c, 0
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ld de, 1
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ld hl, 0xA000
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ri_find_loop:
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push bc
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push de
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push hl
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ld hl, 0x8000
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call read_sector
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pop de
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push de
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ld b, 0 ; Load the filename length in BC
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ld a, (0x8000)
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ld c, a
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inc hl
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ldir
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ld a, (hl)
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ld (de), a
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inc hl
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pop de
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ld a, e
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add a, 0x20
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ld e, a
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ld a, d
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adc a, 0x0
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ld d, a
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ld a, (hl)
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ld (de), a
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inc hl
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inc de
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ld a, (hl)
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ld (de), a
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inc hl
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inc de
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ld l, e
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ld h, d
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pop de
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pop bc
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ld (hl), e
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inc hl
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ld (hl), d
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inc hl
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ld (hl), c
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inc hl
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; Advance to the next header
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ld b, 0 ; Load the filename length in BC
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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 ; Add the filename length to get the pointer to the
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; # of blocks in the file in HL
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ld c, (hl) ; Read the # of blocks into BC
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inc hl
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ld b, (hl)
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ld l, c ; Move it into HL
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ld h, b
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inc hl ; Add 1 to account for the header sector
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pop bc
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add hl, de ; 24-bit add of HL to C: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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jp ri_find_loop
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call proc_map_set ; Register ourselves as ID 1
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pop hl
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ld (mailbox_num), hl
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msg_loop:
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call yield
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ld hl, (mailbox_num)
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call mb_read ; Read a message and place it at 0xB000
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push bc
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push de
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push hl
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ld b, c
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ld c, 0xB
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call set_frame
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ld hl, (0xB004) ; Load destination mailbox into HL
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pop ix
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pop de
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pop bc
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call mb_send
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halt
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jp msg_loop
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halt
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mailbox_num: .ds.b 2
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; Given a sector number in C:DE, reads the sector off disk into 0x8000
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read_sector:
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; Set up a read message to the driver starting at the sector in register E and reading
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; 0x100 bytes
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ld a, 0x0
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ld (0xA000), a
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ld a, e
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ld (0xA001), a
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ld a, 0x00
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ld (0xA002), a
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ld a, 0x1
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ld (0xA003), a
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ld hl, (mailbox_num)
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ld (0xA004), hl
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push de
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push bc
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ld de, 0 ; Get the mailbox number for the initrd driver
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call proc_map_get
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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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ld hl, (mailbox_num)
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call mb_read ; Read a message
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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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read_sector_done:
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ret
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