Enable disassembly of wrap-around tables.

We assume that table offsets can wrap around, in order to access the second
half of the 128KB BIOS. No verification yet, and the offsets look strange.
Moved from mmap()ed I/O to read(), in order to not segfault w/o additional
checks even on small BIOS dumps.
Abstracted table offset fetch into separate function.

1 files changed, 70 insertions, 39 deletions

diff --git a/main.c b/main.c
index cfc7e81..049aa74 100644
--- a/main.c
+++ b/main.c
@@ -30,6 +30,7 @@
 
 
 #define MMAP_SIZE (1024*1024)
+#undef  USE_MMAP   /* too difficult to get big mapping (1MB) of small files) */
 
 
 typedef struct {
@@ -196,6 +197,27 @@ bios_tables_t *get_pointers (uint8_t *data)
     return &tabs;
 }
 
+int get_table_offset(uint16_t *table, int idx) {
+    int i, last = 0, offset = 0;
+    static int wrapwarning = 0;
+
+    if (! table || ! table[idx])
+	return 0;
+
+    for (i = 0; i <= idx; i++) {
+	int off = table[i];
+	if (off) {
+	    if (off < last)
+		offset += 0x10000;
+	    last = off - 0x8000;
+	}
+    }
+
+    if (offset && ! wrapwarning++)
+	printf ("*** Wrap around of table offset - assuming offset\n");
+    return table[idx] + offset;
+}
+
 
 int sub_dest (uint8_t *d, char *out, int type, int align, int size, int index) {
     uint32_t    val;
@@ -435,10 +457,10 @@ void do_list (bios_tables_t *tabs)
 
     fputs ("Command Tables:\n", stdout);
     for (i = 0; i < sizeof (ATOM_MASTER_LIST_OF_COMMAND_TABLES) / sizeof (uint16_t); i++) {
-	if (tabs->MasterCommandTables[i])
+	int off = get_table_offset(tabs->MasterCommandTables, i);
+	if (off)
 	    fprintf (stdout, "  %04x:   %04x  Len %04x",
-		     i, tabs->MasterCommandTables[i],
-		     * (uint16_t *) (tabs->base + tabs->MasterCommandTables[i]));
+		     i, off, * (uint16_t *) (tabs->base+off));
 	else
 	    fprintf (stdout, "  %04x:   -             ", i);
 	if ( (ind = get_index (INDEX_COMMAND_TABLE, i)) )
@@ -449,13 +471,13 @@ void do_list (bios_tables_t *tabs)
     for (i = 0; i < sizeof (ATOM_MASTER_LIST_OF_DATA_TABLES) / sizeof (uint16_t); i++) {
 	data_dumper_t *dt   = NULL;
 	const char *comment = NULL;
-	if (tabs->MasterDataTables[i]) {
-	    uint8_t *data = tabs->base + tabs->MasterDataTables[i];
+	int off = get_table_offset(tabs->MasterDataTables, i);
+	if (off) {
+	    uint8_t *data= tabs->base + off;
 	    int     frev = data[2];
 	    int     crev = data[3];
 	    fprintf (stdout, "  %04x:   %04x  Len %04x  Rev %02x:%02x",
-		     i, tabs->MasterDataTables[i], * (uint16_t *) data,
-		     frev, crev);
+		     i, off, * (uint16_t *) data, frev, crev);
 	    dt = get_data_dumper (i, &frev, &crev, &comment);
 	} else
 	    fprintf (stdout, "  %04x:   -                        ", i);
@@ -470,25 +492,33 @@ void do_list (bios_tables_t *tabs)
 
 int do_tableinfo (uint8_t *data, int off, int type, int nr)
 {
-    int size = * (uint16_t *) (data+off);
-    int frev = *              (data+off+2);
-    int crev = *              (data+off+3);
-    const char *ind = get_index (type, nr);
+    int size, frev, crev;
+    const char *ind;
+
+    if (! data)
+	return 0;
+
+    size = * (uint16_t *) (data+off);
+    frev = *              (data+off+2);
+    crev = *              (data+off+3);
+    ind  = get_index (type, nr);
 
     fprintf (stdout, "%s  %08x", index_tables[type].name, off);
     if (nr >= 0)
 	fprintf (stdout, "  #%02x  (%s)", nr, ind ? ind:"<unknown>");
     fputs (":\n\n", stdout);
-    
+
     if (off)
+	fprintf (stdout, "  Size         %04x\n", size);
+    
+    if (off && size)
 	fprintf (stdout,
-		 "  Size         %04x\n"
 		 "  Format Rev.  %02x\n"
 		 "  Param Rev.   %02x\n"
 		 "  Content Rev. %02x\n",
-		 size, frev & 0x0f, frev >> 4, crev);
+		 frev & 0x0f, frev >> 4, crev);
 
-    if (type == INDEX_COMMAND_TABLE) {
+    if (type == INDEX_COMMAND_TABLE && size) {
 	int attr = * (uint16_t *) (data+off+4);
 	fprintf (stdout,
 		 "  Attributes:  Work space size        %02x longs\n"
@@ -662,13 +692,24 @@ int main (int argc, char *argv[])
 	return 1;
     }
     
+#if USE_MMAP 
     if ( (data = mmap (NULL, MMAP_SIZE, PROT_READ, MAP_PRIVATE, fdmem, opt_off))
 	 == (void *) -1) {
 	perror ("mmap()");
 	return 1;
     }
-
+#else
+    if (! (data = calloc (1, MMAP_SIZE)) ) {
+	perror ("calloc()");
+	return 1;
+    }
+    if ( (len = read (fdmem, data, MMAP_SIZE)) <= 0) {
+	perror ("read()");
+	return 1;
+    }
+    printf ("Read %x bytes of data from %s\n\n", len, argv[optind]);
     init_data_dumpers ();
+#endif
 
     for (arg = &argv[optind+1]; *arg && **arg; arg++) {
 	last_reg_index  = INDEX_NONE;
@@ -699,9 +740,9 @@ int main (int argc, char *argv[])
 	    start = strtol (arg[1], NULL, 16);
 	    arg++;
 	    tabs  = get_pointers (data);
-	    off   = tabs->MasterDataTables [start];
+	    off   = get_table_offset(tabs->MasterDataTables, start);
 	    len   = do_tableinfo (data, off, INDEX_DATA_TABLE, start);
-	    if (off) {
+	    if (off && len) {
 		do_dump (data + off, 4, len);
 		do_data (data + off, 0, start);
 	    }
@@ -712,9 +753,9 @@ int main (int argc, char *argv[])
 	    start = strtol (arg[1], NULL, 16);
 	    arg++;
 	    tabs  = get_pointers (data);
-	    off   = tabs->MasterCommandTables [start];
+	    off   = get_table_offset(tabs->MasterCommandTables, start);
 	    len   = do_tableinfo (data, off, INDEX_COMMAND_TABLE, start);
-	    if (off)
+	    if (off && len)
 		do_diss (data + off, 6, len, opt_addrformat);
 	    break;
 	case 'C':
@@ -738,16 +779,10 @@ int main (int argc, char *argv[])
 		 / sizeof (uint16_t); start++) {
 		last_reg_index  = INDEX_NONE;
 		last_reg_offset = 0;
-		off   = tabs->MasterCommandTables [start];
+		off   = get_table_offset(tabs->MasterCommandTables, start);
 		len   = do_tableinfo (data, off, INDEX_COMMAND_TABLE, start);
-		if (off) {
-		    if (off > last) {
-			do_diss (data + off, 6, len, opt_addrformat);
-			last = off - 0x8000;
-		    } else {
-			fputs ("  *** Wrap around of table offset - multi-segment output not supported yet\n\n", stdout);
-			last = 0x1ffff;
-		    }
+		if (off && len) {
+		    do_diss (data + off, 6, len, opt_addrformat);
 		    fputs ("\n", stdout);
 		}
 	    }
@@ -756,17 +791,11 @@ int main (int argc, char *argv[])
 	    /* Data table #0 is reseverd (SET_DATA_BLOCK 0 == BIOS start */
 	    for (start = 1; start < sizeof (ATOM_MASTER_LIST_OF_DATA_TABLES)
 		 / sizeof (uint16_t); start++) {
-		off   = tabs->MasterDataTables [start];
+		off   = get_table_offset(tabs->MasterDataTables, start);
 		len   = do_tableinfo (data, off, INDEX_DATA_TABLE, start);
-		if (off) {
-		    if (off > last) {
-			do_dump (data + off, 4, len);
-			do_data (data + off, 0, start);
-			last = off - 0x8000;
-		    } else {
-			fputs ("  *** Wrap around of table offset - multi-segment output not supported yet\n\n", stdout);
-			last = 0x1ffff;
-		    }
+		if (off && len) {
+		    do_dump (data + off, 4, len);
+		    do_data (data + off, 0, start);
 		    fputs ("\n", stdout);
 		}
 	    }
@@ -776,7 +805,9 @@ int main (int argc, char *argv[])
 	}
     }
 
+#if USE_MMAP
     munmap (data, MMAP_SIZE);
+#endif
     close  (fdmem);
     return 0;
 }