[Qemu-devel] Re: [PATCH] floppy support for guest-OS OS9/x86 (aka OS9000)

["W. Tasin" <tasin@fhm.edu>]

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Hi,

after re-reading some of your cvs-logs and checking again the data 
sheet, here my second version of fdc1.diff.
This version is IMHO cleaner/saver, because it wouldn't break the hack 
(fdc.c; rev. 1.14) in the SENSE INTERRUPT STATUS and it is more data 
sheet conforming.

Sorry about the first fdc1.diff-"noise".
Ciao

Walter

W. Tasin schrieb:
> Hello *,
>
> I tried to make OS9/x86 runnable on qemu; with an existing hd image it 
> already worked, but w/o floppy support. To make this also available 
> I'd a look at the sources and (after some time ...) I was able to 
> solve 3 little problems.
> - boot from floppy didn't work
> - floppy support inside os9/x86 didn't work
> - a second ide reset sequence didn't work correctly
>
> So here my patches (against snapshot 
> http://qemu-forum.ipi.fi/qemu-snapshots/qemu-snapshot-2007-05-18_05.tar.bz2) 
>
>
> You can find a more detailed explanation on 
> http://pc01-lsw.ee.fhm.edu/wiki/QEmu/OS9Patch
>
> HTH
> Ciao
>
> Walter
>
> PS: Please CC me on questions, 'cause I'm not subscribed to the list.
>

-- 
Walter Tasin, M.Sc.
Fakultät für Elektrotechnik und Informationstechnik
Fachhochschule München, Munich University of Applied Sciences



[-- Attachment #2: fdc1.diff --]
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--- hw/fdc.c	Mon May 21 10:38:54 2007
+++ hw/fdc.c	Mon May 21 10:39:20 2007
@@ -377,6 +377,7 @@
     uint8_t dma_en;
     uint8_t cur_drv;
     uint8_t bootsel;
+    uint8_t first_sense;
     /* Command FIFO */
     uint8_t fifo[FD_SECTOR_LEN];
     uint32_t data_pos;
@@ -597,6 +598,7 @@
     fdctrl->irq = irq;
     fdctrl->dma_chann = dma_chann;
     fdctrl->io_base = io_base;
+    fdctrl->first_sense=0;
     fdctrl->config = 0x60; /* Implicit seek, polling & FIFO enabled */
     if (fdctrl->dma_chann != -1) {
         fdctrl->dma_en = 1;
@@ -655,7 +657,7 @@
 	return;
     }
 #endif
-    if (~(fdctrl->state & FD_CTRL_INTR)) {
+    if (!(fdctrl->state & FD_CTRL_INTR)) {
         qemu_set_irq(fdctrl->irq, 1);
         fdctrl->state |= FD_CTRL_INTR;
     }
@@ -672,6 +674,7 @@
     fdctrl_reset_irq(fdctrl);
     /* Initialise controller */
     fdctrl->cur_drv = 0;
+    fdctrl->first_sense = 4;
     /* FIFO state */
     fdctrl->data_pos = 0;
     fdctrl->data_len = 0;
@@ -1384,6 +1387,7 @@
             FLOPPY_DPRINTF("SPECIFY command\n");
             /* 1 parameter cmd */
             fdctrl->data_len = 3;
+            fdctrl->first_sense=0;
             goto enqueue;
         case 0x04:
             /* SENSE_DRIVE_STATUS */
@@ -1401,21 +1405,29 @@
             /* SENSE_INTERRUPT_STATUS */
             FLOPPY_DPRINTF("SENSE_INTERRUPT_STATUS command (%02x)\n",
                            fdctrl->int_status);
+            uint8_t act_drv = fdctrl->cur_drv;
             /* No parameters cmd: returns status if no interrupt */
+            if (fdctrl->first_sense > 0)
+                act_drv=4-fdctrl->first_sense--;
+
 #if 0
             fdctrl->fifo[0] =
-                fdctrl->int_status | (cur_drv->head << 2) | fdctrl->cur_drv;
+                (fdctrl->state & FD_CTRL_INTR) ? 
+            (fdctrl->int_status | (cur_drv->head << 2) | act_drv) : 0x80;
 #else
             /* XXX: int_status handling is broken for read/write
                commands, so we do this hack. It should be suppressed
                ASAP */
             fdctrl->fifo[0] =
-                0x20 | (cur_drv->head << 2) | fdctrl->cur_drv;
+                (fdctrl->state & FD_CTRL_INTR) ? 
+                (0x20 | (cur_drv->head << 2) | act_drv) : 0x80 ;
 #endif
+
             fdctrl->fifo[1] = cur_drv->track;
-            fdctrl_set_fifo(fdctrl, 2, 0);
-	    fdctrl_reset_irq(fdctrl);
-	    fdctrl->int_status = 0xC0;
+            fdctrl_set_fifo(fdctrl, (fdctrl->fifo[0] != 0x80) ? 2 : 1, 0);
+                
+            fdctrl_reset_irq(fdctrl);
+            fdctrl->int_status = 0xC0;
             return;
         case 0x0E:
             /* DUMPREG */