commit - b6729e0b95ada1c7074add2ca93ce6c01dca8a9c
commit + 9990f831c9f7692866d7dc6608ac48ed0b817f47
blob - 722893b531ef4abd9d897099a15cd772593b7b42
blob + 0392e0db74d8749bc01305b5fd88746df0606704
--- sys/Makefile
+++ sys/Makefile
.SUFFIXES: .asm .o
LDFLAGS = -s --no-pie
-OBJ = loader.o kernel.o
+OBJ = loader.o kernel.o floppy.o
IMG = sys.img
blob - 0c67881007e3e0152772558c01203f1f4e03aebd
blob + 884330b6194faf72eaf12a1617d8742be1236b92
--- sys/kernel.asm
+++ sys/kernel.asm
%include "macros.inc"
section .text
+extern floppy_init
global _entry
+global putchar
+global puts
+global puthexb
+global puthexw
+global panic
_entry:
pop dx
mov byte [bootdrv], dl
lea bp, [kbmsg]
call puts
+ call floppy_init
+
sti
jmp $
blob - /dev/null
blob + 898c63b83194e4a1572e736bb32054468aa279b1 (mode 644)
--- /dev/null
+++ sys/floppy.asm
+[bits 16]
+[cpu 286]
+
+%include "macros.inc"
+
+; Floppy Registers
+SRA equ 0x3f0 ; Status Register A RO
+SRB equ 0x3f1 ; Status Register B RO
+DOR equ 0x3f2 ; Digital Output Register RW
+TDR equ 0x3f3 ; Tape Drive Register RW
+MSR equ 0x3f4 ; Main Status Register RO
+DSR equ 0x3f4 ; Datarate Select Register WO
+DFF equ 0x3f5 ; Data FIFO RW
+DIR equ 0x3f7 ; Digital Input Register RO
+CCR equ 0x3f7 ; Configuration Control Register WO
+
+DOR_MOTD equ 0x80 ; Drive Motor 3 ON
+DOR_MOTC equ 0x40 ; Drive Motor 2 ON
+DOR_MOTB equ 0x20 ; Drive Motor 1 ON
+DOR_MOTA equ 0x10 ; Drive Motor 0 ON
+DOR_IRQ equ 0x08 ; Enable IRQs and DMA
+DOR_NRESET equ 0x04 ; 0=enter reset mode, 1=normal operation
+DOR_DSEL equ 0x03 ; Select drive number mask
+
+MSR_RQM equ 0x80 ; It's OK (or mandatory) to exchange bytes with the FIFO IO port
+MSR_DIO equ 0x40 ; FIFO expects an IN opcode
+MSR_NDMA equ 0x20 ; Set while executing PIO mode read/write commands
+MSR_BSY equ 0x10 ; Command Busy
+MSR_ACTD equ 0x08 ; Drive 3 is seeking
+MSR_ACTC equ 0x04 ; Drive 2 is seeking
+MSR_ACTB equ 0x02 ; Drive 1 is seeking
+MSR_ACTA equ 0x01 ; Drive 0 is seeking
+
+DSR_288M equ 0x03 ; 2.88M floppy (1Mbps)
+DSR_144M equ 0x00 ; 1.44M floppy (500Kbps)
+
+; Floppy drive commands
+CMD_READ_TRACK equ 2 ; IRQ6
+CMD_SPECIFY equ 3 ; set drive parameters
+CMD_SENSE_DRIVE_STATUS equ 4
+CMD_WRITE_DATA equ 5 ; write to disk
+CMD_READ_DATA equ 6 ; read from disk
+CMD_RECALIBRATE equ 7 ; seek to cylinder 0
+CMD_SENSE_INTERRUPT equ 8 ; ack IRQ6, get status of last command
+CMD_WRITE_DELETED_DATA equ 9
+CMD_READ_ID equ 10 ; IRQ6
+CMD_READ_DELETED_DATA equ 12
+CMD_FORMAT_TRACK equ 13
+CMD_DUMPREG equ 14
+CMD_SEEK equ 15 ; seek both heads to cylinder X
+CMD_VERSION equ 16 ; used during initialization, once
+CMD_SCAN_EQUAL equ 17
+CMD_PERPENDICULAR_MODE equ 18 ; used during initialization, once, maybe
+CMD_CONFIGURE equ 19 ; set controller parameters
+CMD_LOCK equ 20 ; protect controller parameters from reset
+CMD_VERIFY equ 22
+CMD_SCAN_LOW_OR_EQUAL equ 25
+CMD_SCAN_HIGH_OR_EQUAL equ 29
+
+CMD_MT equ 0x80 ; multitrack mode
+CMD_MF equ 0x40 ; "MFM" magnetic encoding mode. Always set for read/write/format/verify
+CMD_SK equ 0x20 ; Skip mode. Skips "deleted sectors"
+
+
+section .text
+extern puthexb
+extern putchar
+extern puts
+extern panic
+global floppy_init
+floppy_init:
+ lea bp, [fimsg]
+ call puts
+
+ ; read what types of floppy drives we have
+ outb_slow 0x70, 0x90
+ in al, 0x71
+ mov byte [floppy_type], al
+ call puthexb
+
+ mov al, 10
+ call putchar
+
+ lea bp, [vermsg]
+ call puts
+
+ call version
+ call puthexb
+
+ mov al, 10
+ call putchar
+
+ ret
+
+wait_rqm:
+ push cx
+ mov cx, 128
+
+.again:
+ dec cx
+ jz error
+
+ mov dx, MSR
+ in al, dx
+ test al, MSR_RQM
+ jz .again
+
+ pop cx
+ ret
+
+version:
+ mov cx, 3
+
+.begin:
+ dec cx
+ jz error
+
+ ; wait for the controller
+ mov dx, MSR
+ in al, dx
+ and al, (MSR_RQM | MSR_DIO)
+ cmp al, MSR_RQM
+ jne .reset
+
+ ; send version command
+ mov al, CMD_VERSION
+ mov dx, DFF
+ out dx, al
+
+ ; wait for version byte
+ call wait_rqm
+ test al, MSR_DIO
+ jz error
+
+ ; read version byte
+ mov dx, DFF
+ in al, dx
+ mov bl, al
+
+ ; wait for completion
+ call wait_rqm
+
+ ; verify result
+ mov dx, MSR
+ in al, dx
+ and al, (MSR_RQM | MSR_BSY | MSR_DIO)
+ cmp al, MSR_RQM
+ jne .retry
+ mov al, bl
+ ret
+
+.retry:
+ push cx
+ lea bp, [rtmsg]
+ call puts
+ pop cx
+ jmp .begin
+
+.reset:
+ push cx
+ call reset
+ pop cx
+ jmp .begin
+
+reset:
+ lea bp, [rsmsg]
+ jmp puts
+
+error:
+ lea bp, [errstr]
+ jmp panic
+
+; ax LBA
+; return:
+; - bx cyl
+; - cx head
+; - dx sector
+lba_to_cha:
+ xor dx, dx
+ mov cx, 36
+ div cx
+ mov bx, ax ; cyl
+ mov ax, dx
+ xor dx, dx
+ mov cx, 18
+ div cx
+ mov cx, ax ; head
+ inc dx ; sector
+ ret
+
+section .rodata
+errstr:
+ db "An error occured in the floppy driver", 10, 0
+fimsg:
+ db "Floppy drive type: 0x", 0
+vermsg:
+ db "Floppy drive version: 0x", 0
+rsmsg:
+ db "Resetting floppy drive...", 10, 0
+rtmsg:
+ db "Retrying last operating", 10, 0
+
+section .bss
+floppy_type:
+ resb 1
