Skip to content

Fix AliM1543C sector calculation and read race #117

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
RaymiiOrg merged 2 commits into from
Apr 15, 2026
Merged

Fix AliM1543C sector calculation and read race #117

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
fb4b907
Fix AliM1543C sector calculation
hvolkmer Apr 9, 2026
e98f586
AliM1543C: Use fresh value for reads
hvolkmer Apr 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 17 additions & 6 deletions src/AliM1543C_ide.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -736,10 +736,20 @@ void CAliM1543C_ide::ide_command_write(int index, u32 address, int dsize,
u32 CAliM1543C_ide::ide_control_read(int index, u32 address) {
u32 data = 0;
switch (address) {
case 0: {
SCOPED_READ_LOCK(mtRegisters[index]);
data = SEL_STATUS(index).alt_status;
}
case 0:
// Compute status live from current state rather than using cached
// alt_status, to avoid stale values when the controller thread has
// updated status fields but not yet called UPDATE_ALT_STATUS.
// Unlike get_status(), this does not affect index_pulse or clear interrupts.
if (SEL_DISK(index)) {
data = (SEL_STATUS(index).busy ? 0x80 : 0x00) |
(SEL_STATUS(index).drive_ready ? 0x40 : 0x00) |
(SEL_STATUS(index).fault ? 0x20 : 0x00) |
(SEL_STATUS(index).seek_complete ? 0x10 : 0x00) |
(SEL_STATUS(index).drq ? 0x08 : 0x00) |
(SEL_STATUS(index).index_pulse ? 0x02 : 0x00) |
(SEL_STATUS(index).err ? 0x01 : 0x00);
}
#ifdef DEBUG_IDE_REG_CONTROL
static u32 last_data = 0;
if (last_data != data) {
Expand Down Expand Up @@ -1368,7 +1378,8 @@ void CAliM1543C_ide::execute(int index) {
}
}
}


UPDATE_ALT_STATUS(index);
raise_interrupt(index);
}
break;
Expand Down Expand Up @@ -1828,7 +1839,7 @@ void CAliM1543C_ide::execute(int index) {
// set the next block to read.
// increment the lba.
SEL_REGISTERS(index).sector_no +=
CONTROLLER(index).data_size * 256; // # sectors read.
CONTROLLER(index).data_size / 256; // # sectors read.
if (SEL_REGISTERS(index).sector_no > 255) {
SEL_REGISTERS(index).sector_no = 0;
SEL_REGISTERS(index).cylinder_no++;
Expand Down
Loading