Better implementation of FDC 'not found' errors - can now distinguish missing

address mark (eg disc not present or track not formatted), sector not found,
wrong cylinder and bad cylinder.

src/disc.c

@@ -143,7 +143,7 @@ void disc_poll()
         {
                 disc_notfound--;
                 if (!disc_notfound)
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_AM_NOT_FOUND);
         }
 }
 

src/disc.h

@@ -37,7 +37,7 @@ void fdc_callback();
 int  fdc_data(uint8_t dat);
 void fdc_spindown();
 void fdc_finishread();
-void fdc_notfound();
+void fdc_notfound(int reason);
 void fdc_datacrcerror();
 void fdc_headercrcerror();
 void fdc_writeprotect();

src/disc_fdi.c

@@ -3,6 +3,7 @@
 #include "ibm.h"
 #include "disc.h"
 #include "disc_fdi.h"
+#include "fdc.h"
 #include "fdi2raw.h"
 
 static struct
@@ -314,7 +315,7 @@ void fdi_poll()
                 if (fdi_revs == 3)
                 {
 //                        pclog("Not found!\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_NOT_FOUND);
                         fdi_inread = fdi_inreadaddr = 0;
                         return;
                 }

src/disc_sector.c

@@ -47,6 +47,8 @@ static uint8_t disc_sector_fill;
 static int cur_sector, cur_byte;
 static int index_count;
 
+static int disc_sector_status;
+
 void disc_sector_reset(int drive, int side)
 {
         disc_sector_count[drive][side] = 0;
@@ -90,6 +92,8 @@ void disc_sector_readsector(int drive, int sector, int track, int side, int rate
         disc_sector_sector = sector;
 	disc_sector_n = sector_size;
         index_count = 0;
+        
+        disc_sector_status = FDC_STATUS_AM_NOT_FOUND;
 }
 
 void disc_sector_writesector(int drive, int sector, int track, int side, int rate, int sector_size)
@@ -103,6 +107,8 @@ void disc_sector_writesector(int drive, int sector, int track, int side, int rat
         disc_sector_sector = sector;
 	disc_sector_n = sector_size;
         index_count = 0;
+
+        disc_sector_status = FDC_STATUS_AM_NOT_FOUND;
 }
 
 void disc_sector_readaddress(int drive, int track, int side, int rate)
@@ -114,6 +120,8 @@ void disc_sector_readaddress(int drive, int track, int side, int rate)
         disc_sector_side  = side;
         disc_sector_drive = drive;
         index_count = 0;
+
+        disc_sector_status = FDC_STATUS_AM_NOT_FOUND;
 }
 
 void disc_sector_format(int drive, int track, int side, int rate, uint8_t fill)
@@ -179,7 +187,7 @@ void disc_sector_poll()
                 if (index_count > 1)
                 {
 //                        pclog("Find sector not found\n");
-                        fdc_notfound();
+                        fdc_notfound(disc_sector_status);
                         disc_sector_state = STATE_IDLE;
                         break;
                 }
@@ -187,10 +195,11 @@ void disc_sector_poll()
                     disc_sector_side != s->h,
                     disc_sector_sector != s->r,
                     fdc_get_bitcell_period() != get_bitcell_period());*/
-                if (cur_byte || disc_sector_track != s->c ||
+                if (!cur_byte && fdc_get_bitcell_period() == get_bitcell_period() &&
-                    disc_sector_side != s->h ||
+                    fdd_can_read_medium(disc_sector_drive ^ fdd_swap))
-                    disc_sector_sector != s->r ||
+                        disc_sector_status = FDC_STATUS_NOT_FOUND; /*Disc readable, assume address marker found*/
-		    disc_sector_n != s->n ||
+                    
+                if (cur_byte ||
                     fdc_get_bitcell_period() != get_bitcell_period() ||
 		    !fdd_can_read_medium(disc_sector_drive ^ fdd_swap) ||
                     disc_intersector_delay)
@@ -198,6 +207,16 @@ void disc_sector_poll()
                         advance_byte();
                         break;
                 }
+                if (disc_sector_track != s->c ||
+                    disc_sector_side != s->h ||
+                    disc_sector_sector != s->r ||
+		    disc_sector_n != s->n)
+                {
+                        if (disc_sector_track != s->c)
+                                disc_sector_status = (disc_sector_track == 0xff) ? FDC_STATUS_BAD_CYLINDER : FDC_STATUS_WRONG_CYLINDER;
+                        advance_byte();
+                        break;
+                }
                 disc_sector_state = STATE_READ_SECTOR;
                 case STATE_READ_SECTOR:
 //                pclog("STATE_READ_SECTOR: cur_byte=%i %i\n", cur_byte, disc_intersector_delay);
@@ -218,10 +237,14 @@ void disc_sector_poll()
 		if (!(fdd_can_read_medium(disc_sector_drive ^ fdd_swap)))
 		{
 //			pclog("Medium is of a density not supported by the drive\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_AM_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
 		}
+                if (!cur_byte && fdc_get_bitcell_period() == get_bitcell_period() &&
+                    fdd_can_read_medium(disc_sector_drive ^ fdd_swap))
+                        disc_sector_status = FDC_STATUS_NOT_FOUND; /*Disc readable, assume address marker found*/
+
                 if (cur_byte || !index_count || fdc_get_bitcell_period() != get_bitcell_period() ||
                     disc_intersector_delay)
                 {
@@ -244,14 +267,14 @@ void disc_sector_poll()
 		if (!(fdd_can_read_medium(disc_sector_drive ^ fdd_swap)))
 		{
 //			pclog("Medium is of a density not supported by the drive\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_AM_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
 		}
                 if (index_count)
                 {
 //                        pclog("Find next sector hit end of track\n");
-                        fdc_notfound();
+                        fdc_notfound(disc_sector_status);
                         disc_sector_state = STATE_IDLE;
                         break;
                 }
@@ -277,10 +300,15 @@ void disc_sector_poll()
 		if (!(fdd_can_read_medium(disc_sector_drive ^ fdd_swap)))
 		{
 //			pclog("Medium is of a density not supported by the drive\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_AM_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
 		}
+
+                if (!cur_byte && fdc_get_bitcell_period() == get_bitcell_period() &&
+                    fdd_can_read_medium(disc_sector_drive ^ fdd_swap))
+                        disc_sector_status = FDC_STATUS_NOT_FOUND; /*Disc readable, assume address marker found*/
+
                 if (writeprot[disc_sector_drive])
                 {
                         fdc_writeprotect();
@@ -290,20 +318,27 @@ void disc_sector_poll()
                 if (index_count > 1)
                 {
 //                        pclog("Write find sector not found\n");
-                        fdc_notfound();
+                        fdc_notfound(disc_sector_status);
                         disc_sector_state = STATE_IDLE;
                         break;
                 }
-                if (cur_byte || disc_sector_track != s->c ||
+                if (cur_byte ||
-                    disc_sector_side != s->h ||
-                    disc_sector_sector != s->r ||
-		    disc_sector_n != s->n ||
                     fdc_get_bitcell_period() != get_bitcell_period() ||
                     disc_intersector_delay)
                 {
                         advance_byte();
                         break;
                 }
+                if (disc_sector_track != s->c ||
+                    disc_sector_side != s->h ||
+                    disc_sector_sector != s->r ||
+		    disc_sector_n != s->n)
+                {
+                        if (disc_sector_track != s->c)
+                                disc_sector_status = (disc_sector_track == 0xff) ? FDC_STATUS_BAD_CYLINDER : FDC_STATUS_WRONG_CYLINDER;
+                        advance_byte();
+                        break;
+                }
                 disc_sector_state = STATE_WRITE_SECTOR;
                 case STATE_WRITE_SECTOR:
                 data = fdc_getdata(cur_byte == ((128 << s->n) - 1));
@@ -323,14 +358,19 @@ void disc_sector_poll()
 		if (!(fdd_can_read_medium(disc_sector_drive ^ fdd_swap)))
 		{
 //			pclog("Medium is of a density not supported by the drive\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_AM_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
 		}
+
+                if (!cur_byte && fdc_get_bitcell_period() == get_bitcell_period() &&
+                    fdd_can_read_medium(disc_sector_drive ^ fdd_swap))
+                        disc_sector_status = FDC_STATUS_NOT_FOUND; /*Disc readable, assume address marker found*/
+
                 if (index_count)
                 {
 //                        pclog("Find next sector hit end of track\n");
-                        fdc_notfound();
+                        fdc_notfound(disc_sector_status);
                         disc_sector_state = STATE_IDLE;
                         break;
                 }
@@ -343,6 +383,7 @@ void disc_sector_poll()
                 disc_sector_state = STATE_READ_ADDRESS;
                 case STATE_READ_ADDRESS:
                 fdc_sectorid(s->c, s->h, s->r, s->n, 0, 0);
+                advance_byte();
                 disc_sector_state = STATE_IDLE;
                 break;
                 
@@ -362,13 +403,13 @@ void disc_sector_poll()
 		if (!(fdd_can_read_medium(disc_sector_drive ^ fdd_swap)))
 		{
 //			pclog("Medium is of a density not supported by the drive\n");
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
 		}
                 if (fdc_get_bitcell_period() != get_bitcell_period())
                 {
-                        fdc_notfound();
+                        fdc_notfound(FDC_STATUS_NOT_FOUND);
                         disc_sector_state = STATE_IDLE;
                         break;
                 }

src/fdc.c

@@ -5,12 +5,23 @@
 #include "disc.h"
 #include "disc_sector.h"
 #include "dma.h"
+#include "fdc.h"
 #include "fdd.h"
 #include "io.h"
 #include "pic.h"
 #include "timer.h"
 #include "x86.h"
 
+#define ST1_DE (1 << 5)
+#define ST1_ND (1 << 2)
+#define ST1_NW (1 << 1)
+#define ST1_MA (1 << 0)
+
+#define ST2_DD (1 << 5)
+#define ST2_WC (1 << 4) /*Wrong cylinder*/
+#define ST2_BC (1 << 1) /*Bad cylinder*/
+#define ST2_MD (1 << 0)
+
 static int fdc_reset_stat = 0;
 /*FDC*/
 typedef struct FDC
@@ -790,7 +801,6 @@ uint8_t fdc_read(uint16_t addr, void *priv)
 void fdc_callback()
 {
         int temp;
-        int doseek = 0;
         int drive;
         
 //        pclog("fdc_callback %i\n", discint);
@@ -1187,15 +1197,33 @@ void fdc_finishread()
 //        rpclog("fdc_finishread\n");
 }
 
-void fdc_notfound()
+void fdc_notfound(int reason)
 {
+//        pclog("fdc_notfound: reason=%i\n", reason);
         timer_disable(&fdc.timer);
 
         fdc_int();
         fdc.stat=0xD0;
         fdc.res[4]=0x40|(fdc.head?4:0)|fdc.drive;
-        fdc.res[5]=5;
+        switch (reason)
-        fdc.res[6]=0;
+        {
+                case FDC_STATUS_AM_NOT_FOUND:
+                fdc.res[5] = ST1_ND | ST1_MA;
+                fdc.res[6] = 0;
+                break;
+                case FDC_STATUS_NOT_FOUND:
+                fdc.res[5] = ST1_ND;
+                fdc.res[6] = 0;
+                break;
+                case FDC_STATUS_WRONG_CYLINDER:
+                fdc.res[5] = ST1_ND;
+                fdc.res[6] = ST2_WC;
+                break;
+                case FDC_STATUS_BAD_CYLINDER:
+                fdc.res[5] = ST1_ND;
+                fdc.res[6] = ST2_WC | ST2_BC;
+                break;
+        }
         fdc.res[7] = fdc.rw_track;
         fdc.res[8] = fdc.head;
         fdc.res[9] = fdc.sector;

src/fdc.h

@@ -24,3 +24,13 @@ void fdc_update_boot_drive(int boot_drive);
 void fdc_update_densel_polarity(int densel_polarity);
 void fdc_update_densel_force(int densel_force);
 void fdc_update_drvrate(int drive, int drvrate);
+
+
+
+enum
+{
+        FDC_STATUS_AM_NOT_FOUND,
+        FDC_STATUS_NOT_FOUND,
+        FDC_STATUS_WRONG_CYLINDER,
+        FDC_STATUS_BAD_CYLINDER
+};