Hi
Freedos floppy image was failing when I tried to boot it, because INSB
instruction is not emulated. So by looking at INSW logic in io.c, I have
added the following emulation for INSB instruction. This is my first
attempt at adding instructions to Plex86, so I maybe wrong.
If Kevin, or anyone else who knows about adding instructions to plex86 can
tell if what I have added is right or wrong, it will be very useful.
However the booting problem in Freedos is still not solved, as It is
failing in dma and I have forgotten about 8237 dma controller, to try and
identify as to what the exact problem is with the DMA error. Or is it that
I am not emulating INSB properly, which inturn is affecting the DMA logic
indirectly or so.
The PATCH follows
diff -Naur plex86/kernel/emulation/emulation.c plex86.han/kernel/emulation/emulation.c
--- plex86/kernel/emulation/emulation.c Tue Nov 21 14:31:09 2000
+++ plex86.han/kernel/emulation/emulation.c Wed Nov 22 14:32:43 2000
@@ -587,6 +587,10 @@
case 0x6a: /* PUSH_Ib (byte extended to word or dword) */
PUSH_Iv(vm);
goto advance;
+
+ case 0x6c:
+ INSB_YbDX(vm);
+ goto advance;
case 0x6d:
INSW_YvDX(vm);
diff -Naur plex86/kernel/emulation/io.c plex86.han/kernel/emulation/io.c
--- plex86/kernel/emulation/io.c Tue Nov 21 11:10:58 2000
+++ plex86.han/kernel/emulation/io.c Wed Nov 22 14:38:17 2000
@@ -24,6 +24,48 @@
#include "monitor.h"
+ void
+INSB_YbDX(vm_t *vm)
+ /* input byte from port to string */
+{
+ Bit32u edi;
+ unsigned int incr;
+ Bit8u value8=0;
+
+ if (vm->i.as_32)
+ edi = G_EDI(vm);
+ else
+ edi = G_DI(vm);
+
+ IOPermCheck(vm, G_DX(vm), 1);
+
+ /* Write a zero to memory, to trigger any segment or page */
+ /* faults before reading from IO port. */
+ write_virtual_byte(vm, SRegES, edi, &value8);
+
+ value8 = sysIOIn(vm, G_DX(vm), 1);
+ /* Not working ???
+ monprint("IOport: %d Value: %d\n",G_DX(vm),value8);
+ */
+
+ /* no seg override allowed */
+ write_virtual_byte(vm, SRegES, edi, &value8);
+ incr = 1;
+
+ if (vm->i.as_32) {
+ if (G_GetDF(vm))
+ G_EDI(vm) -= incr;
+ else
+ G_EDI(vm) += incr;
+ }
+ else {
+ if (G_GetDF(vm))
+ G_DI(vm) -= incr;
+ else
+ G_DI(vm) += incr;
+ }
+}
+
void
INSW_YvDX(vm_t *vm)
diff -Naur plex86/kernel/include/emulation.h plex86.han/kernel/include/emulation.h
--- plex86/kernel/include/emulation.h Tue Nov 21 14:31:09 2000
+++ plex86.han/kernel/include/emulation.h Wed Nov 22 13:38:56 2000
@@ -143,6 +143,7 @@
void LODSB_ALXb(vm_t *);
void TEST_EbIb(vm_t *);
void LOOP_Jb(vm_t *);
+void INSB_YbDX(vm_t *);
void INSW_YvDX(vm_t *);
void CALL16_Ep(vm_t *);
void CALL_Ew(vm_t *);
---------
Keep :-)
HanishKVC
http://www.hanishkvc.com/
