modified project to support Qt Creator inferior debugging through BDM.

.gdbinit

@@ -1,5 +1,6 @@
 #set disassemble-next-line on
 define tr
+	!killall m68k-bdm-gdbserver
 	target remote | m68k-bdm-gdbserver pipe /dev/bdmcf3
 	#target remote | m68k-bdm-gdbserver pipe /dev/tblcf3
 	#target dbug /dev/ttyS0

BaS_gcc.files

@@ -228,3 +228,4 @@ COPYING
 COPYING.LESSER
 dump.bdm
 mcf5474.gdb
+Makefile

Makefile

@@ -39,6 +39,7 @@ CFLAGS=-mcpu=5474 \
 		-Wa,--register-prefix-optional
 CFLAGS_OPTIMIZED = -mcpu=5474 \
 		-Wall \
+		-g3 \
 		-O2 \
 		-fomit-frame-pointer \
 		-ffreestanding \

mcf5474.gdb

@@ -61,6 +61,10 @@ define ib
 	setup-dram
 end
 
+define run
+	continue
+end
+
 tr
 ib
-load
+load firebee/ram.elf

sys/exceptions.S

@@ -509,7 +509,7 @@ irq6:	// MFP interrupt from FPGA
 		movem.l	(sp),d0-d1/a0-a1	// restore registers saved above
 		lea		4 * 4(sp),sp		// adjust stack
 
-		bra		irq6_os				// call OS handler
+		beq		irq6_os				// call OS handler
 		rte
 
 irq6_os:	// call native OS irq6 handler

sys/mmu.c

@@ -204,20 +204,20 @@ static int num_locked_mmu_maps = sizeof(locked_map) / sizeof(struct mmu_mapping)
 
 static struct mmu_mapping memory_map[] =
 {
-    /* map system vectors supervisor-protected */
+	/* map OS system vectors supervisor-protected */
 	{
 		0,
 		0,
 		0x800,
 		MMU_PAGE_SIZE_1K,
-        { CACHE_WRITETHROUGH, SV_USER, 0, ACCESS_READ | ACCESS_WRITE | ACCESS_EXECUTE },
+		{ CACHE_WRITETHROUGH, SV_PROTECT, 0, ACCESS_READ | ACCESS_WRITE | ACCESS_EXECUTE },
 	},
 	{
 		0x800,
 		0x800,
 		0x800,
 		MMU_PAGE_SIZE_1K,
-        { CACHE_WRITETHROUGH, SV_USER, 0, ACCESS_READ | ACCESS_WRITE | ACCESS_EXECUTE },
+		{ CACHE_WRITETHROUGH, SV_PROTECT, 0, ACCESS_READ | ACCESS_WRITE | ACCESS_EXECUTE },
 	},
 	{
 		/* when the first 4k are filled with 1k pages, we can switch to 8k pages */
@@ -434,7 +434,11 @@ bool access_exception(uint32_t pc, uint32_t format_status)
 		case 0x8020000:	/* TLB miss on data write */
 		case 0xc020000:	/* TLB miss on data read or read-modify-write */
 			fault_address = MCF_MMU_MMUAR;
-            dbg("access fault - TLB miss at %p. Fault status = 0x0%x\r\n", pc, fault_status);
+			/*
+			 * the following line must stay commented or we risk a double fault (debugging
+			 * output requiring itself a page mapping):
+			 */
+			// dbg("access fault - TLB miss at %p. Fault status = 0x0%x\r\n", pc, fault_status);
 			break;
 
 		default:

sys/sysinit.c

@@ -1093,6 +1093,7 @@ void initialize_hardware(void)
 
 	/* the following only makes sense _after_ DDRAM has been initialized */
 	clear_bss_segment();
+	xprintf(".bss segment cleared\r\n");
 
 	if (BAS_LMA != BAS_IN_RAM)
 	{