[fuse-emulator-cvs] [fuse] 01/02: Fix SCAN bug in uPD765 FDC

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sbaldovi pushed a commit to branch master
in repository fuse.

View the commit online:
https://sourceforge.net/p/fuse-emulator/fuse/ci/ce0a650efb17b01ca2e1a780afdb44fa2607f7c6/

commit ce0a650efb17b01ca2e1a780afdb44fa2607f7c6
Author: Gergely Szasz <sz...@hu...>
AuthorDate: Sat Oct 21 06:23:01 2023 +0200

    Fix SCAN bug in uPD765 FDC
    
    Allows to format a disk on CP/M Plus and Fuzix (fixes bug #453)
    (thanks, Phil Reynolds and Vic Chwe).
---
 peripherals/disk/upd_fdc.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/peripherals/disk/upd_fdc.c b/peripherals/disk/upd_fdc.c
index b1263e4d..9e10e87c 100644
--- a/peripherals/disk/upd_fdc.c
+++ b/peripherals/disk/upd_fdc.c
@@ -688,6 +688,8 @@ abort_read_data:
   f->main_status |= UPD_FDC_MAIN_DATAREQ;
   if( f->cmd->id != UPD_CMD_SCAN )
     f->main_status |= UPD_FDC_MAIN_DATA_READ;
+  else
+    f->main_status |= UPD_FDC_MAIN_DATA_WRITE;
   f->data_offset = 0;
   event_remove_type( timeout_event );
   event_add_with_data( tstates + 4 *			/* 2 revolution: 2 * 200 / 1000  */
@@ -871,7 +873,7 @@ upd_fdc_event( libspectrum_dword last_tstates GCC_UNUSED, int event,
   }
   
   if( f->read_id ) {
-    if( f->cmd->id == UPD_CMD_READ_DATA ) {
+    if( f->cmd->id == UPD_CMD_READ_DATA || f->cmd->id == UPD_CMD_SCAN ) {
       start_read_data( f );
     } else if( f->cmd->id == UPD_CMD_READ_ID ) {
       start_read_id( f );
@@ -1013,7 +1015,7 @@ upd_fdc_write_data( upd_fdc *f, libspectrum_byte data )
     return;
 
   if( f->main_status & UPD_FDC_MAIN_BUSY && 
-      f->state == UPD_FDC_STATE_EXE ) {	/* execution phase WRITE/FORMAT */
+      f->state == UPD_FDC_STATE_EXE ) {        /* execution phase WRITE/FORMAT/SCAN */
     d = f->current_drive;
     if( f->cmd->id == UPD_CMD_WRITE_ID ) {	/* FORMAT */
 		/* at the index hole... */
@@ -1120,7 +1122,7 @@ upd_fdc_write_data( upd_fdc *f, libspectrum_byte data )
     } else {						/* SCAN */
       f->data_offset++;
       fdd_read_data( d ); crc_add( f, d );
-      if( f->data_offset == 0 && d->data == data )	/* `scan hit' */
+      if( f->data_offset == 1 && d->data == data )     /* `scan hit' */
         f->status_register[2] |= UPD_FDC_ST2_SCAN_HIT;
 
       if( d->data != data )				/* `scan _not_ hit' */
@@ -1366,6 +1368,9 @@ upd_fdc_write_data( upd_fdc *f, libspectrum_byte data )
 							     UPD_SCAN_LO;
 
       f->rlen = 0x80 << ( f->data_register[4] > MAX_SIZE_CODE ? MAX_SIZE_CODE : f->data_register[4] );
+      f->first_rw = 1;         /* always read at least one sector */
+      if( f->data_register[4] == 0 && f->data_register[7] < 128 )
+        f->rlen = f->data_register[7];
       head_load( f );
       return;
     }