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Fix FAT chain termination and harden SD driver error handling

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alex
2026-10-07 22:53:51 +03:00
parent 0e300bf5fd
commit b5856a7787
8 changed files with 1002 additions and 443 deletions
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_sd/tests/test_fat_offsets.py
+32 -4
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@@ -20,9 +20,16 @@ class Driver:
self.m = z80.Z80Machine()
self.m.set_memory_block(0, BODY)
self.disk = {}
self.fail_reads = set()
self.fail_writes = set()
self.io = []
self.ram = bytearray(256 * 16384)
self.hooks = {SYMS[n]: n for n in
('sdread_lba', 'sdread_lba_to', 'sdwrite_lba', 'write_fsinfo_hint')}
('sdread_lba', 'sdread_lba_to', 'sdwrite_lba',
'sdwrite_lba_from', 'write_fsinfo_hint')}
self.hooks.update({SYMS[n]: n for n in
('sdwrite_multi_start', 'sdwrite_multi_block', 'sdwrite_multi_stop')})
self.multi_lba = None
for address in [0xff00, *self.hooks]:
self.m.set_breakpoint(address)
self.put('reserved_sectors', 32)
@@ -59,9 +66,28 @@ class Driver:
hook = self.hooks.get(self.m.pc)
if not hook:
continue
if hook != 'write_fsinfo_hint':
failed = False
if hook == 'sdwrite_multi_start':
p = SYMS['lba_arg']
self.multi_lba = int.from_bytes(self.m.memory[p:p+4], 'big')
elif hook == 'sdwrite_multi_stop':
self.multi_lba = None
elif hook == 'sdwrite_multi_block':
assert self.multi_lba is not None
p = SYMS['sdbuf']
self.disk[self.multi_lba] = bytearray(self.m.memory[p:p+512])
self.io.append((hook, self.multi_lba))
self.multi_lba += 1
elif hook != 'write_fsinfo_hint':
lba = int.from_bytes(self.m.memory[SYMS['lba_arg']:SYMS['lba_arg']+4], 'big')
if hook == 'sdwrite_lba':
self.io.append((hook, lba))
failed = lba in (self.fail_reads if hook.startswith('sdread') else self.fail_writes)
if failed:
pass
elif hook == 'sdwrite_lba_from':
source = self.get('dma_xfer_page', 1)*16384 + (self.get('dma_xfer_off') & 16383)
self.disk[lba] = self.ram[source:source+512]
elif hook == 'sdwrite_lba':
p = SYMS['sdbuf']
self.disk[lba] = bytearray(self.m.memory[p:p+512])
elif hook == 'sdread_lba':
@@ -72,9 +98,11 @@ class Driver:
else:
dest = self.get('dma_xfer_page', 1)*16384 + (self.get('dma_xfer_off') & 16383)
self.ram[dest:dest+512] = self.disk[lba]
self.m.af = 0x0040 # A=0, Z=1 (successful sector I/O)
self.m.af = 0x0100 if failed else 0x0040
self.m.pc = int.from_bytes(self.m.memory[self.m.sp:self.m.sp+2], 'little')
self.m.sp += 2
if self.m.pc == 0xff00:
return self.m.a
raise AssertionError(f'{name}: execution did not return')