(Game Boy Advance) Program begins at 0x00000000 instead of 0x08000000. How to tell gcc to compile to a specific address?

Question

I've got DevKitPro working on Game Boy Advance, but I've run into a few problems. The biggest one I see is that my code is assembled at 0x00000000 instead of the normal 0x08000000 for ROM cartridges. My understanding is that C compilers don't use an .org directive to create the code at a specified memory location; rather the linker is supposed to take care of all that for me. But it seems to be placing the code at the "wrong" address. The game will run correctly, but I imagine this is because it's running on an emulator and the emulator doesn't care that it's located somewhere it shouldn't be. How do I get the code to be "assembled" at 0x08000000?

I'm new to the concept of makefiles, compilers, linkers, etc. so I probably have everything set up very poorly. I'll show my makefile, batch script that runs the makefile, and the C code that's being compiled. I've also included the objdump in case that's relevant.

C code:

// LIBGBA HEADERS
#include 
#include 
#include 
#include 
#include 
#include 
#include 
// GAME-SPECIFIC INCLUDES
#include "M:\SrcGBA\PaintBoyAdvance\include\bitmap.h"   
#include "M:\SrcGBA\PaintBoyAdvance\include\bitmap.c"   //BITMAP SCREEN FUNCTIONS

//---------------------------------------------------------------------------------
// Program entry point
//---------------------------------------------------------------------------------
int main(void) {
//---------------------------------------------------------------------------------


    // the vblank interrupt must be enabled for VBlankIntrWait() to work 
    // since the default dispatcher handles the bios flags no vblank handler
    // is required
    irqInit();
    irqEnable(IRQ_VBLANK);
    

    // consoleDemoInit();
    REG_DISPCNT = 0x1403;


    while (1) {
        VBlankIntrWait();
    }
}

Batch script:

@echo off
set path=C:\devkitPro\;%path%
cd M:\SrcGBA\PaintBoyAdvance
make
if not "%errorlevel%"=="0" goto Abandon

C:\devkitPro\devkitARM\bin\arm-none-eabi-objdump -h M:\SrcGBA\PaintBoyAdvance\build\paintboyadvance.o

C:\Users\puppy\Documents\VisualBoyAdvance\visualboyadvance-m.exe M:\SrcGBA\PaintBoyAdvance\PaintBoyAdvance.gba
:Abandon

exit

Makefile:

#---------------------------------------------------------------------------------
.SUFFIXES:
#---------------------------------------------------------------------------------

ifeq ($(strip $(DEVKITARM)),)
$(error "Please set DEVKITARM in your environment. export DEVKITARM=devkitARM")
endif

include $(DEVKITARM)/gba_rules

#---------------------------------------------------------------------------------
# TARGET is the name of the output
# BUILD is the directory where object files & intermediate files will be placed
# SOURCES is a list of directories containing source code
# INCLUDES is a list of directories containing extra header files
# DATA is a list of directories containing binary data
# GRAPHICS is a list of directories containing files to be processed by grit
#
# All directories are specified relative to the project directory where
# the makefile is found
#
#---------------------------------------------------------------------------------
TARGET      := $(notdir $(CURDIR))
BUILD       := build
SOURCES     := source
INCLUDES    := include
DATA        := data
MUSIC       :=

#---------------------------------------------------------------------------------
# options for code generation
#---------------------------------------------------------------------------------
ARCH    :=  -mthumb -mthumb-interwork
SPECS   :=  -specs=gba.specs

CFLAGS  :=  -g -Wall -O2\
        -mcpu=arm7tdmi -mtune=arm7tdmi\
        -ffreestanding \
        $(ARCH)

CFLAGS  :=  $(INCLUDE)

CXXFLAGS    :=  $(CFLAGS) -fno-rtti -fno-exceptions 

ASFLAGS :=  -g $(ARCH)
LDFLAGS =   -g $(ARCH) $(INCLUDE) -Wl,-Map,$(notdir $@.map)

#---------------------------------------------------------------------------------
# any extra libraries we wish to link with the project
#---------------------------------------------------------------------------------
LIBS    := -lmm -lgba


#---------------------------------------------------------------------------------
# list of directories containing libraries, this must be the top level containing
# include and lib
#---------------------------------------------------------------------------------
LIBDIRS :=  $(LIBGBA)

#---------------------------------------------------------------------------------
# no real need to edit anything past this point unless you need to add additional
# rules for different file extensions
#---------------------------------------------------------------------------------


ifneq ($(BUILD),$(notdir $(CURDIR)))
#---------------------------------------------------------------------------------

export OUTPUT   :=  $(CURDIR)/$(TARGET)

export VPATH    :=  $(foreach dir,$(SOURCES),$(CURDIR)/$(dir)) \
            $(foreach dir,$(DATA),$(CURDIR)/$(dir)) \
            $(foreach dir,$(GRAPHICS),$(CURDIR)/$(dir))

export DEPSDIR  :=  $(CURDIR)/$(BUILD)

CFILES      :=  $(foreach dir,$(SOURCES),$(notdir $(wildcard $(dir)/*.c)))
CPPFILES    :=  $(foreach dir,$(SOURCES),$(notdir $(wildcard $(dir)/*.cpp)))
SFILES      :=  $(foreach dir,$(SOURCES),$(notdir $(wildcard $(dir)/*.s)))
BINFILES    :=  $(foreach dir,$(DATA),$(notdir $(wildcard $(dir)/*.*)))

ifneq ($(strip $(MUSIC)),)
    export AUDIOFILES   :=  $(foreach dir,$(notdir $(wildcard $(MUSIC)/*.*)),$(CURDIR)/$(MUSIC)/$(dir))
    BINFILES += soundbank.bin
endif

#---------------------------------------------------------------------------------
# use CXX for linking C++ projects, CC for standard C
#---------------------------------------------------------------------------------
ifeq ($(strip $(CPPFILES)),)
#---------------------------------------------------------------------------------
    export LD   :=  $(CC)
#---------------------------------------------------------------------------------
else
#---------------------------------------------------------------------------------
    export LD   :=  $(CXX)
#---------------------------------------------------------------------------------
endif
#---------------------------------------------------------------------------------

export OFILES_BIN := $(addsuffix .o,$(BINFILES))

export OFILES_SOURCES := $(CPPFILES:.cpp=.o) $(CFILES:.c=.o) $(SFILES:.s=.o)

export OFILES := $(OFILES_BIN) $(OFILES_SOURCES)

export HFILES := $(addsuffix .h,$(subst .,_,$(BINFILES)))

export INCLUDE  :=  $(foreach dir,$(INCLUDES),-iquote $(CURDIR)/$(dir)) \
                    $(foreach dir,$(LIBDIRS),-I$(dir)/include) \
                    -I$(CURDIR)/$(BUILD)

export LIBPATHS :=  $(foreach dir,$(LIBDIRS),-L$(dir)/lib)

.PHONY: $(BUILD) clean

#---------------------------------------------------------------------------------
$(BUILD):
    @[ -d $@ ] || mkdir -p $@
    @$(MAKE) --no-print-directory -C $(BUILD) -f $(CURDIR)/Makefile

#---------------------------------------------------------------------------------
clean:
    @echo clean ...
    @rm -fr $(BUILD) $(TARGET).elf $(TARGET).gba


#---------------------------------------------------------------------------------
else

#---------------------------------------------------------------------------------
# main targets
#---------------------------------------------------------------------------------

$(OUTPUT).gba   :   $(OUTPUT).elf

$(OUTPUT).elf   :   $(OFILES)

$(OFILES_SOURCES) : $(HFILES)

#---------------------------------------------------------------------------------
# The bin2o rule should be copied and modified
# for each extension used in the data directories
#---------------------------------------------------------------------------------

#---------------------------------------------------------------------------------
# rule to build soundbank from music files
#---------------------------------------------------------------------------------
soundbank.bin soundbank.h : $(AUDIOFILES)
#---------------------------------------------------------------------------------
    @mmutil $^ -osoundbank.bin -hsoundbank.h

#---------------------------------------------------------------------------------
# This rule links in binary data with the .bin extension
#---------------------------------------------------------------------------------
%.bin.o %_bin.h :   %.bin
#---------------------------------------------------------------------------------
    @echo $(notdir $<)
    @$(bin2o)


-include $(DEPSDIR)/*.d
#---------------------------------------------------------------------------------------
endif
#---------------------------------------------------------------------------------------

Output of object dump:

M:\SrcGBA\PaintBoyAdvance\build\paintboyadvance.o:     file format elf32-littlearm

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000268  00000000  00000000  00000034  2**2
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
  1 .data         00000000  00000000  00000000  0000029c  2**0
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          00000000  00000000  00000000  0000029c  2**0
                  ALLOC
  3 .comment      00000024  00000000  00000000  0000029c  2**0
                  CONTENTS, READONLY
  4 .ARM.attributes 0000002a  00000000  00000000  000002c0  2**0
                  CONTENTS, READONLY

EDIT: As requested here is the output of the batch file:

\SrcGBA\PaintBoyAdvance\compile.bat paintboyadvance.c M:\SrcGBA\PaintBoyAdvance\source nopause
Process started >>>
paintboyadvance.c
linking cartridge
built ... PaintBoyAdvance.gba
ROM fixed!

M:\SrcGBA\PaintBoyAdvance\build\paintboyadvance.o:     file format elf32-littlearm

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000280  00000000  00000000  00000034  2**2
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
  1 .data         00000000  00000000  00000000  000002b4  2**0
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          00000000  00000000  00000000  000002b4  2**0
                  ALLOC
  3 .comment      00000024  00000000  00000000  000002b4  2**0
                  CONTENTS, READONLY
  4 .ARM.attributes 0000002a  00000000  00000000  000002d8  2**0
                  CONTENTS, READONLY

(Game Boy Advance) Program begins at 0x00000000 instead of 0x08000000. How to tell gcc to compile to a specific address?

Answers (1)

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