Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-04-16 21:44:32 +03:00
Code Issues Actions Packages Projects Releases Wiki Activity

hdc92x4: Fixed wrong fill byte after data CRC (had no functional impact) (nw)

Browse Source
This commit is contained in:
Michael Zapf 2020-12-14 18:08:34 +01:00
parent 7905b3b308
commit eb61e292c4
1 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/devices/machine/hdc92x4.cpp
View File

@ -2825,10 +2825,14 @@ void hdc92x4_device::live_run_until(attotime limit)
write_on_track(encode((m_live_state.crc >> 8) & 0xff), 1, WRITE_DATA_CRC);
}
else
{
// Write a filler byte so that the last CRC bit is saved correctly
// Without, the last bit of the CRC value may be flipped
write_on_track(encode(0xff), 1, WRITE_DONE);
// This is an effect of the PLL, not of MFM
// Compare with the header CRC, where during formatting, the
// CRC bytes are followed by the gap bytes.
write_on_track(encode(fm_mode()? 0xff : 0x4e), 1, WRITE_DONE);
}
break;
case WRITE_DONE:
@ -3572,9 +3576,11 @@ void hdc92x4_device::live_run_hd_until(attotime limit)
write_on_track(encode_hd((m_live_state.crc >> 8) & 0xff), 1, WRITE_DATA_CRC);
}
else
{
// Write a filler byte so that the last CRC bit is saved correctly
write_on_track(encode_hd(0xff), 1, WRITE_DONE);
// See above for an explanation
write_on_track(encode_hd(0x4e), 1, WRITE_DONE);
}
break;
case WRITE_DONE: