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disk.py
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# (C) 2020 by Folkert van Heusden <[email protected]>
# released under AGPL v3.0
import struct
import sys
from pagetype import PageType
class disk:
T1_BUSY = 0x01
T1_INDEX = 0x02
T1_TRACK0 = 0x04
T1_CRCERR = 0x08
T1_SEEKERR = 0x10
T1_HEADLOAD = 0x20
T1_PROT = 0x40
T1_NOTREADY = 0x80
T2_BUSY = 0x01
T2_DRQ = 0x02
T2_NOTREADY = 0x80
def __init__(self, disk_rom_file, debug, disk_image_file):
print('Loading disk rom %s...' % disk_rom_file, file=sys.stderr)
fh = open(disk_rom_file, 'rb')
self.disk_rom = [ int(b) for b in fh.read() ]
fh.close()
self.fh = open(disk_image_file, 'ab+')
self.regs = [ 0 ] * 16
self.buffer = [ 0 ] * 512
self.bufp = 0
self.need_flush = False
self.tc = None
self.flags = 0
self.step_dir = 1
self.debug = debug
def file_offset(self, side, track, sector):
return (sector - 1)* 512 + (track * 9 * 512) + (80 * 9 * 512) * side;
def get_signature(self):
return (self.disk_rom, PageType.DISK, self)
def write_mem(self, a, v):
offset = a - 0x4000
if offset >= 0x3ff0: # HW registers
reg = offset - 0x3ff0
self.debug('Write DISK register %02x: %02x' % (reg, v))
if reg == 0x08:
command= v >> 4
T = (v >> 4) & 1;
h = (v >> 3) & 1;
V = (v >> 2) & 1;
r1 = (v >> 1) & 1;
r0 = (v ) & 1;
m = (v >> 4) & 1;
S = (v >> 3) & 1;
E = (v >> 2) & 1;
C = (v >> 1) & 1;
A0 = (v ) & 1;
i = (v & 15);
if command == 0: # restore
self.regs[0x09] = 0
self.tc = 1
self.flags = self.T1_INDEX | self.T1_TRACK0
if h:
self.flags |= self.T1_HEADLOAD
elif command == 1: # seek
self.regs[0x09] = self.regs[0x0b]
self.tc = 1
self.flags = self.T1_INDEX | self.T1_TRACK0
if h:
self.flags |= self.T1_HEADLOAD
elif command == 2 or command == 3: # step
self.regs[0x09] += self.step_dir
if self.regs[0x09] < 0:
self.regs[0x09] = 0
elif self.regs[0x09] > 79:
self.regs[0x09] = 79
self.tc = 1
self.flags = self.T1_INDEX
if self.regs[0x09] == 0:
self.flags |= self.T1_TRACK0
elif command == 4 or command == 5: # step-in
self.regs[0x09] += 1
if self.regs[0x09] > 79:
self.regs[0x09] = 79
self.step_dir = 1
self.tc = 1
self.flags = self.T1_INDEX
if self.regs[0x09] == 0:
self.flags |= self.T1_TRACK0;
elif command == 6 or command == 7: # step-out
self.regs[0x09] -= 1
if self.regs[0x09] < 0:
self.regs[0x09] = 0
self.step_dir = -1
self.tc = 1
self.flags = self.T1_INDEX
if self.regs[0x09] == 0:
self.flags |= self.T1_TRACK0;
elif command == 8 or command == 9: # read sector
self.bufp = 0
self.need_flush = False
side = 1 if (self.regs[0x0c] & 10) == 10 else 0
o = self.file_offset(side, self.regs[0x09], self.regs[0x0a])
self.debug('Read sector %d:%d:%d (offset %d)' % (side, self.regs[0x09], self.regs[0x0a], o))
self.fh.seek(o)
for i in range(0, 512):
b = self.fh.read(1)
if len(b) == 0:
b = 0
else:
self.buffer[i] = struct.unpack('<B', b)[0]
self.tc = 2
self.flags |= self.T2_BUSY | self.T2_DRQ
elif command == 10 or command == 11: # write sector
self.bufp = 0
self.need_flush = True
self.tc = 2
self.flags |= self.T2_BUSY | self.T2_DRQ
elif command == 12:
self.tc = 3
self.flags |= self.T2_BUSY | self.T2_DRQ
elif command == 13:
self.bufp = 0
self.tc = 4
elif command == 14:
self.tc = 3
self.debug('Read track %d' % self.regs[0x09])
self.flags |= self.T2_BUSY | self.T2_DRQ
elif command == 15:
self.tc = 3
self.debug('Write track %d' % self.regs[0x09])
self.flags |= self.T2_BUSY | self.T2_DRQ
else:
print('%d' % command, file=sys.stderr)
assert False
elif reg == 0x0b: # data register
if self.bufp < 512:
self.buffer[self.bufp] = v
self.bufp += 1
if self.bufp == 512 and self.need_flush:
side = 1 if (self.regs[0x0c] & 0x10) == 0x10 else 0
o = self.file_offset(side, self.regs[0x09], self.regs[0x0a])
self.debug('Write sector %d:%d:%d (offset %o)' % (side, self.regs[0x09], self.regs[0x0a], o))
self.fh.seek(o)
self.fh.write(bytes(self.buffer))
self.fh.flush()
self.flags &= ~(self.T2_DRQ | self.T2_BUSY)
else:
self.flags |= self.T2_DRQ
elif reg == 0x0c: # side
if (v & 0x04) == 0x04: # reset
self.regs[0x09] = 0
else:
self.regs[reg] = v
def read_mem(self, a):
offset = a - 0x4000
if offset >= 0x3ff0: # HW registers
reg = offset - 0x3ff0
# self.debug('Read DISK register %02x' % reg)
if reg == 0x08:
if self.tc == 1 or self.tc == 4:
v = self.flags
self.flags &= self.T1_NOTREADY
self.flags &= self.T1_BUSY
return v
elif self.tc == 2 or self.tc == 3:
return self.flags
elif reg == 0x0b:
if self.bufp < 512:
v = self.buffer[self.bufp]
self.bufp += 1
self.flags |= self.T2_DRQ
return v
else:
self.flags &= ~(self.T2_DRQ | self.T2_BUSY | 32)
elif reg == 0x0f:
v = 0
if self.flags & self.T2_DRQ:
v |= 128
self.flags &= ~self.T2_DRQ
if self.flags & self.T2_BUSY:
v |= 64
return v
return self.regs[reg]
return self.disk_rom[offset]