Added debugging statements

diff --git a/src/arch/i386/interface/pcbios/biosint.c b/src/arch/i386/interface/pcbios/biosint.c
index 6028998a14ec189ce376feb6c868b894badf55ab..5a48f0479fdf958da03c938ac056b8ed56ee78ec 100644 (file)
--- a/src/arch/i386/interface/pcbios/biosint.c
+++ b/src/arch/i386/interface/pcbios/biosint.c
@@ -37,13 +37,21 @@ void hook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
                .offset = handler,
        };
 
+       DBG ( "Hooking INT %#02x to %04x:%04x\n",
+             interrupt, rm_cs, handler );
+
        if ( ( chain_vector->segment != 0 ) ||
             ( chain_vector->offset != 0 ) ) {
                /* Already hooked; do nothing */
+               DBG ( "...already hooked\n" );
                return;
        }
+
        copy_from_real ( chain_vector, 0, ( interrupt * 4 ),
                         sizeof ( *chain_vector ) );
+       DBG ( "...chaining to %04x:%04x\n",
+             chain_vector->segment, chain_vector->offset );
+
        copy_to_real ( 0, ( interrupt * 4 ), &vector, sizeof ( vector ) );
        hooked_bios_interrupts++;
 }
@@ -65,11 +73,21 @@ int unhook_bios_interrupt ( unsigned int interrupt, unsigned int handler,
                            struct segoff *chain_vector ) {
        struct segoff vector;
 
+       DBG ( "Unhooking INT %#02x from %04x:%04x\n",
+             interrupt, rm_cs, handler );
+
        copy_from_real ( &vector, 0, ( interrupt * 4 ), sizeof ( vector ) );
-       if ( ( vector.segment != rm_cs ) || ( vector.offset != handler ) )
+       if ( ( vector.segment != rm_cs ) || ( vector.offset != handler ) ) {
+               DBG ( "...cannot unhook; vector points to %04x:%04x\n",
+                     vector.segment, vector.offset );
                return -EBUSY;
+       }
+
+       DBG ( "...restoring to %04x:%04x\n",
+             chain_vector->segment, chain_vector->offset );
        copy_to_real ( 0, ( interrupt * 4 ), chain_vector,
                       sizeof ( *chain_vector ) );
+
        chain_vector->segment = 0;
        chain_vector->offset = 0;
        hooked_bios_interrupts--;