In case of read or write errors, the floppy system is usually reset and the operation is retried. In that case, the floppy motor state must be preserved in order to avoid creating jitter and keep the floppy motor spinning smoothly at a constant speed. Additionally, the drive select bits should probably also be preserved, because some systems might need a small delay after selecting a new drive. In that case, the operation would be retried, without changing the currently selected drive.
In floppy_enable_controller(), the IRQ bit is now enabled first, before the reset bit is set. I'm not completely sure whether this is necessary. It is done just in case some hardware introduces a delay between setting this bit and actually enabling the IRQ, which would cause us to miss the IRQ, sent by the controller immediately after reset.
Signed-off-by: Nikolay Nikolov nickysn@users.sourceforge.net --- src/hw/floppy.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/src/hw/floppy.c b/src/hw/floppy.c index 992983d..573c45f 100644 --- a/src/hw/floppy.c +++ b/src/hw/floppy.c @@ -212,7 +212,8 @@ static void floppy_disable_controller(void) { dprintf(2, "Floppy_disable_controller\n"); - floppy_dor_write(0x00); + // Clear the reset bit (enter reset state) and clear 'enable IRQ and DMA' + floppy_dor_mask(FLOPPY_DOR_IRQ | FLOPPY_DOR_RESET, 0); }
static int @@ -324,8 +325,10 @@ floppy_enable_controller(void) { dprintf(2, "Floppy_enable_controller\n"); SET_BDA(floppy_motor_counter, FLOPPY_MOTOR_TICKS); - floppy_dor_write(0x00); - floppy_dor_write(FLOPPY_DOR_IRQ | FLOPPY_DOR_RESET); + // Clear the reset bit (enter reset state), but set 'enable IRQ and DMA' + floppy_dor_mask(FLOPPY_DOR_RESET, FLOPPY_DOR_IRQ); + // Set the reset bit (normal operation) and keep 'enable IRQ and DMA' on + floppy_dor_mask(0, FLOPPY_DOR_IRQ | FLOPPY_DOR_RESET); int ret = floppy_wait_irq(); if (ret) return ret;