diff --git a/.gitignore b/.gitignore
index e1600820c6..9f10eb5b13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,5 +23,6 @@ tools/*
 *.dump
 *.sa*
 Thumbs.db
+build/
 .DS_Store
 *.ddump
diff --git a/Makefile b/Makefile
index e176b12582..dd1a96ebbc 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ CPP      := $(DEVKITARM)/bin/arm-none-eabi-cpp
 CPPFLAGS := -I tools/agbcc/include -iquote include -nostdinc -undef
 
 LD      := $(DEVKITARM)/bin/arm-none-eabi-ld
-LDFLAGS := -T ld_script.ld -Map pokeemerald.map
+LDFLAGS := -T ld_script.ld -Map ../../pokeemerald.map
 
 OBJCOPY := $(DEVKITARM)/bin/arm-none-eabi-objcopy
 
@@ -35,17 +35,22 @@ RAMSCRGEN := tools/ramscrgen/ramscrgen
 
 .PHONY: rom clean compare tidy
 
+
+$(shell mkdir -p build/ build/emerald/{,asm,data,src})
+
 C_SRCS := $(wildcard src/*.c)
-C_OBJS := $(C_SRCS:%.c=%.o)
+C_OBJS := $(C_SRCS:%.c=build/emerald/%.o)
 
 ASM_SRCS := $(wildcard asm/*.s)
-ASM_OBJS := $(ASM_SRCS:%.s=%.o)
+ASM_OBJS := $(ASM_SRCS:%.s=build/emerald/%.o)
 
 DATA_ASM_SRCS := $(wildcard data/*.s)
-DATA_ASM_OBJS := $(DATA_ASM_SRCS:%.s=%.o)
+DATA_ASM_OBJS := $(DATA_ASM_SRCS:%.s=build/emerald/%.o)
 
 OBJS := $(C_OBJS) $(ASM_OBJS) $(DATA_ASM_OBJS)
 
+$OBJS_REL := $(OBJS:build/emerald/%=%)
+
 ROM := pokeemerald.gba
 ELF := $(ROM:.gba=.elf)
 
@@ -59,8 +64,10 @@ clean: tidy
 	find . \( -iname '*.1bpp' -o -iname '*.4bpp' -o -iname '*.8bpp' -o -iname '*.gbapal' -o -iname '*.lz' -o -iname '*.latfont' -o -iname '*.hwjpnfont' -o -iname '*.fwjpnfont' \) -exec rm {} +
 
 tidy:
-	rm -f ld_script.ld sym_bss.ld sym_common.ld sym_ewram.ld
-	rm -f $(ROM) $(ELF) $(OBJS) $(C_SRCS:%.c=%.i) pokeemerald.map
+	rm -f pokeemerald.gba
+	rm -f pokeemerald.map
+	rm -f pokeemerald.elf
+	rm -r build/*
 
 include graphics_file_rules.mk
 
@@ -75,56 +82,58 @@ include graphics_file_rules.mk
 %.lz: % ; $(GFX) $< $@
 %.rl: % ; $(GFX) $< $@
 
-src/libc.o: CC1 := tools/agbcc/bin/old_agbcc
-src/libc.o: CFLAGS := -O2
+%src/libc.o: CC1 := tools/agbcc/bin/old_agbcc
+%src/libc.o: CFLAGS := -O2
 
-src/siirtc.o: CFLAGS := -mthumb-interwork
+%src/siirtc.o: CFLAGS := -mthumb-interwork
 
-src/agb_flash.o: CFLAGS := -O -mthumb-interwork
-src/agb_flash_1m.o: CFLAGS := -O -mthumb-interwork
-src/agb_flash_mx.o: CFLAGS := -O -mthumb-interwork
+%src/agb_flash.o: CFLAGS := -O -mthumb-interwork
+%src/agb_flash_1m.o: CFLAGS := -O -mthumb-interwork
+%src/agb_flash_mx.o: CFLAGS := -O -mthumb-interwork
 
-src/m4a_2.o: CC1 := tools/agbcc/bin/old_agbcc
-src/m4a_4.o: CC1 := tools/agbcc/bin/old_agbcc
+%src/m4a_2.o: CC1 := tools/agbcc/bin/old_agbcc
+%src/m4a_4.o: CC1 := tools/agbcc/bin/old_agbcc
 
 ifeq ($(NODEP),)
-%.o: c_dep = $(shell $(SCANINC) $*.c)
+build/emerald/src/%.o: c_dep = $(shell $(SCANINC) src/$(*F).c)
 else
-%.o: c_dep :=
+build/emerald/src/%.o: c_dep :=
 endif
 
-$(C_OBJS): %.o : %.c $$(c_dep)
-	@$(CPP) $(CPPFLAGS) $< -o $*.i
-	@$(PREPROC) $*.i charmap.txt | $(CC1) $(CFLAGS) -o $*.s
-	@echo -e ".text\n\t.align\t2, 0\n" >> $*.s
-	$(AS) $(ASFLAGS) -o $@ $*.s
+build/emerald/%.o : %.c $$(c_dep)
+	@$(CPP) $(CPPFLAGS) $< -o build/emerald/$*.i
+	@$(PREPROC) build/emerald/$*.i charmap.txt | $(CC1) $(CFLAGS) -o build/emerald/$*.s
+	@echo -e ".text\n\t.align\t2, 0\n" >> build/emerald/$*.s
+	$(AS) $(ASFLAGS) -o $@ build/emerald/$*.s
 
 ifeq ($(NODEP),)
-%.o: asm_dep = $(shell $(SCANINC) $*.s)
+build/emerald/asm/%.o: asm_dep = $(shell $(SCANINC) asm/$(*F).s)
+build/emerald/data/%.o: asm_dep = $(shell $(SCANINC) data/$(*F).s)
 else
-%.o: asm_dep :=
+build/emerald/asm/%.o: asm_dep :=
+build/emerald/data/%.o: asm_dep :=
 endif
 
-$(ASM_OBJS): %.o: %.s $$(asm_dep)
+build/emerald/asm/%.o: asm/%.s $$(asm_dep)
 	$(AS) $(ASFLAGS) -o $@ $<
 
-$(DATA_ASM_OBJS): %.o: %.s $$(asm_dep)
+build/emerald/data/%.o: data/%.s $$(asm_dep)
 	$(PREPROC) $< charmap.txt | $(AS) $(ASFLAGS) -o $@
 
-sym_bss.ld: sym_bss.txt
-	$(RAMSCRGEN) .bss sym_bss.txt ENGLISH >$@
+build/emerald/sym_bss.ld: sym_bss.txt
+	cd build/emerald && ../../$(RAMSCRGEN) .bss ../../sym_bss.txt ENGLISH >sym_bss.ld
 
-sym_common.ld: sym_common.txt $(C_OBJS) $(wildcard common_syms/*.txt)
-	$(RAMSCRGEN) COMMON sym_common.txt ENGLISH -c src,common_syms >$@
+build/emerald/sym_common.ld: sym_common.txt $(C_OBJS) $(wildcard common_syms/*.txt)
+	cd build/emerald && ../../$(RAMSCRGEN) COMMON ../../sym_common.txt ENGLISH -c src,../../common_syms >sym_common.ld
 
-sym_ewram.ld: sym_ewram.txt
-	$(RAMSCRGEN) ewram_data sym_ewram.txt ENGLISH >$@
+build/emerald/sym_ewram.ld: sym_ewram.txt
+	cd build/emerald && ../../$(RAMSCRGEN) ewram_data ../../sym_ewram.txt ENGLISH >sym_ewram.ld
 
-ld_script.ld: ld_script.txt sym_bss.ld sym_common.ld sym_ewram.ld
-	sed -f ld_script.sed ld_script.txt >ld_script.ld
+build/emerald/ld_script.ld: ld_script.txt build/emerald/sym_bss.ld build/emerald/sym_common.ld build/emerald/sym_ewram.ld
+	cd build/emerald && sed -f ../../ld_script.sed ../../ld_script.txt | sed "s#tools/#../../tools/#g" | sed "s#sound/#../../sound/#g" >ld_script.ld
 
-$(ELF): ld_script.ld $(OBJS)
-	$(LD) $(LDFLAGS) -o $@ $(OBJS) $(LIBGCC)
+pokeemerald.elf: build/emerald/ld_script.ld $(OBJS)
+	cd build/emerald && $(LD) $(LDFLAGS) -o ../../$@ $(OBJS_REL) ../../$(LIBGCC)
 
-$(ROM): $(ELF)
+pokeemerald.gba: %.gba: %.elf
 	$(OBJCOPY) -O binary --gap-fill 0xFF --pad-to 0x9000000 $< $@