debug: move the debug_rom defines to a seperate file

debug_rom/Makefile

@@ -7,12 +7,9 @@ OBJCOPY = $(RISCV)/bin/riscv64-unknown-elf-objcopy
 COMPILE = $(CC) -nostdlib -nostartfiles -I.. -Tlink.ld
 
 ELFS = debug_rom
-DEPS = debug_rom.S link.ld
+DEPS = debug_rom.S link.ld debug_rom_defines.h
 
-all: $(patsubst %,%.h,$(ELFS)) $(patsubst %,%_defines.h,$(ELFS))
-
-%_defines.h: %.S
-	grep define $^ > $@
+all: $(patsubst %,%.h,$(ELFS))
 
 %.h:	%.raw
 	xxd -i $^ | sed "s/^unsigned/static const unsigned/" > $@

debug_rom/debug_rom_defines.h

@@ -1,9 +1,22 @@
+// See LICENSE file for license details.
+
+#ifndef DEBUG_ROM_DEFINES_H
+#define DEBUG_ROM_DEFINES_H
+
+// These are implementation-specific addresses in the Debug Module
 #define DEBUG_ROM_HALTED    0x100
 #define DEBUG_ROM_GOING     0x104
 #define DEBUG_ROM_RESUMING  0x108
 #define DEBUG_ROM_EXCEPTION 0x10C
+
+// Region of memory where each hart has 1
+// byte to read.
 #define DEBUG_ROM_FLAGS 0x400
 #define DEBUG_ROM_FLAG_GO     0
 #define DEBUG_ROM_FLAG_RESUME 1
+
+// These needs to match the link.ld         
 #define DEBUG_ROM_WHERETO 0x300
 #define DEBUG_ROM_ENTRY   0x800
+
+#endif