diff --git a/Makefile b/Makefile
index ee6613f..bb6d41b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,161 @@
-## Temporary things there
+#! /usr/bin/make -f
+#---
+#
+#	gint project Makefile.
+#
+#---
+
+
+
+#---
+#	Project variables.
+#---
+
+# Modules
+modules-gint	= bopti core display gray keyboard mpu screen tales timer
+modules-libc	= setjmp string
+
+# Targets
+target-g1a	= gintdemo.g1a
+target-lib	= libgint.a
+target-std	= libc.a
+
+# Tools
+cc	= sh3eb-elf-gcc
+as	= sh3eb-elf-as
+ar	= sh3eb-elf-ar
+ob	= sh3eb-elf-objcopy
+wr	= g1a-wrapper
+
+# Flags
+cflags		= -m3 -mb -nostdlib -I include -ffreestanding -std=c11
+
+# Demo application (could be done better)
+demo-src	= $(notdir $(wildcard demo/*.[cs]))
+demo-ld		= demo/gintdemo.ld
+demo-icon	= demo/icon.bmp
+demo-res	= $(notdir $(wildcard demo/resources/*))
+demo-obj	= $(patsubst %,build/demo_%.o,$(demo-src) $(demo-res))
+demo-elf	= build/gintdemo.elf
+demo-bin	= build/gintdemo.bin
+demo-libs	= -lgcc -L. -lgint -lc
+
+
+
+#---
+#	Automatic variables.
+#---
+
+# Modules are subfolders of src/.
+modules = $(modules-gint) $(modules-libc)
+
+define n
+# This is a newline character.
+
+endef
+
+# Module-scope variables.
+$(foreach mod, $(modules), $(eval \
+	mod-$(mod)-c	= $(notdir $(wildcard src/$(mod)/*.c))		$n\
+	mod-$(mod)-asm	= $(notdir $(wildcard src/$(mod)/*.s))		$n\
+	mod-$(mod)-dep	= $(wildcard include/*.h src/$(mod)/*.h)	$n\
+	mod-$(mod)-src	= $$(mod-$(mod)-c)$$(mod-$(mod)-asm)		$n\
+	mod-$(mod)-obj	= $$(patsubst %,build/$(mod)_%.o,$$(mod-$(mod)-src)) \
+))
+
+# Target-scope variables.
+obj-std = $(foreach mod,$(modules-libc),$(mod-$(mod)-obj))
+obj-lib	= $(foreach mod,$(modules-gint),$(mod-$(mod)-obj))
+
+
+
+#---
+#	Rule templates.
+#---
 
 # C source file template:
 #   $1  module name
-#   $2  file base name
+#   $2  filename
 define rule-c-source
-build/$1_$2.c.o: src/$1/$2.c
-	$(cc) $(cflags) -c $$< -o $$@
+build/$1_$2.o: src/$1/$2 $(mod-$1-dep)
+	$(cc) -c $$< -o $$@ $(cflags) -I src/$1 -O2
 endef
 
-$(eval $(call rule-c-source,display,area))
+# asm source file template:
+#   $1  module name
+#   $2  filename
+define rule-asm-source
+build/$1_$2.o: src/$1/$2
+	$(as)  -c $$< -o $$@
+endef
+
+
+
+#---
+#	Building.
+#---
+
+# Generic rules
+
+all: build $(target-std) $(target-lib) $(target-g1a)
+	@ echo 'All done!'
+
+build:
+	mkdir -p $@
+
+$(target-std): $(obj-std)
+	$(ar) rcs $@ $^
+
+$(target-lib): $(target-std) $(obj-lib)
+	$(ar) rcs $@ $(obj-lib)
+
+$(target-g1a): $(target-std) $(target-lib) $(demo-obj)
+	$(cc) -o $(demo-elf) $(cflags) -T $(demo-ld) $(demo-obj) $(demo-libs)
+	$(ob) -R .comment -R .bss -O binary $(demo-elf) $(demo-bin)
+	$(wr) $(demo-bin) -o $@ -i $(demo-icon)
+
+# Automated rules
+
+$(foreach mod,$(modules), \
+	$(foreach source,$(mod-$(mod)-c), $(eval \
+		$(call rule-c-source,$(mod),$(source)))) \
+	$(foreach source,$(mod-$(mod)-asm), $(eval \
+		$(call rule-asm-source,$(mod),$(source)))) \
+)
+
+# This one should not be optimized. It makes __attribute__((interrupt_handler))
+# buggy... maybe. Anyway there's a bug in this file.
+build/core_gint.c.o: src/core/gint.c $(mod-core-dep)
+	$(cc) -c $< -o $@ $(cflags) -I src/core
+
+# Demo application
+
+build/demo_%.c.o: demo/%.c
+	$(cc) -c $< -o $@ $(cflags)
+
+build/demo_%.bmp.o: demo/resources/%.bmp
+	fxconv $< -o $@ -n $(patsubst demo/resources/%.bmp,res_%,$<)
+
+build/demo_font.bmp.o: demo/resources/font.bmp
+	fxconv $< -o $@ --font -n res_font
+
+
+
+#---
+#	Cleaning and others.
+#---
+
+clean:
+	@ rm -rf build/*
+
+mrproper: clean
+	@ rm -f $(target-g1a) $(target-lib) $(target-std)
+	@ rm -rf build
+
+distclean: mrproper
+
+install:
+	usb-connector SEND $(target-g1a) $(target-g1a) fls0
+
+
+.PHONY: all clean mrproper distclean
diff --git a/TODO b/TODO
index 9f62af2..81094a0 100644
--- a/TODO
+++ b/TODO
@@ -12,6 +12,7 @@
 @  vram overflow
 @  keyboard test threading interface
 
++  gint vs. ML with 248x124 at (-60, -28)
 +  use alloca() for tales
 +  call exit handlers
 +  compute frequencies
@@ -26,6 +27,7 @@
 +  bitmap parts
 +  bitmap clipping
 
+-  install critical failure handler to prevent failing resets
 -  write and test gray engine
 -  full rtc driver (time)
 -  callbacks and complete user API
@@ -34,3 +36,15 @@
 ~  exhaustive save for setjmp()
 ~  registers that need to be saved when configuring gint
 ~  possible bug when -O2 __attribute__((interrupt_handler))
+
+
+
+Some notes
+----------
+
+Test cases for bitmap drawing:
+- aligned 32 / non-aligned 32
+- monochrome / gray
+- small / large
+- does not overflow / overflows
+# blending modes
diff --git a/demo/gintdemo.c b/demo/gintdemo.c
index c357690..f41d596 100644
--- a/demo/gintdemo.c
+++ b/demo/gintdemo.c
@@ -10,15 +10,14 @@
 #include <stdint.h>
 #include <7305.h>
 
-extern unsigned int bgint, egint;
-
 //---
-//	A few procedures for displaying text in the system's vram.
+//	A few ugly procedures for displaying text. Will have to enhance this
+//	soon -- which means printf().
 //---
 
 void print(const char *str, int x, int y)
 {
-	print_raw(str, x, y);
+	dtext(str, x, y);
 }
 void print_hex(unsigned int n, int x, int y)
 {
@@ -60,6 +59,24 @@ void print_hexa(unsigned int n, int digits, int x, int y)
 	ch[digits] = 0;
 	print(ch, x, y);
 }
+void print_int(int n, int x, int y)
+{
+	char str[20] = { 0 };
+	int i, o = 0;
+	int digits = 0, copy = n;
+
+	if(!n) { str[o++] = '0'; print(str, x, y); return; }
+	if(n < 0) str[o++] = '-', n = -n;
+	while(copy) digits++, copy /= 10;
+
+	for(i = 0; i < digits; i++)
+	{
+		str[o + digits - i - 1] = n % 10 + '0';
+		n /= 10;
+	}
+
+	gtext(str, x, y);
+}
 
 
 
@@ -109,14 +126,16 @@ void keyboard_test(void)
 
 	timer_start(TIMER_USER, 1700, TIMER_Po_256, keyboard_test_timer, 0);
 
+	dclear();
+	print("Keyboard state:", 0, 0);
+	print("multi-getkey ^^", 50, 55);
+	dupdate();
+
 	while(1)
 	{
 		multigetkey(keys, 4, 0);
 		if(keys[0] == KEY_EXIT && keys[1] == KEY_NONE) break;
 
-		dclear();
-		print("Keyboard state:", 0, 0);
-		print("multi-getkey ^^", 50, 55);
 
 		#define	hexa(h) ('0' + (h) + 39 * ((h) > 9))
 
@@ -141,109 +160,73 @@ void keyboard_test(void)
 	timer_stop(TIMER_USER);
 }
 
-
-
-/*
-const unsigned char data[1024] = {
-0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-0, 0, 0, 0, 0, 0, 0, 7, 159, 0, 0, 1, 192, 0, 0, 0, 0, 0, 121, 240, 0, 0, 0,
-31, 191, 192, 0, 3, 224, 27, 216, 0, 0, 1, 251, 252, 0, 0, 0, 57, 247, 222,
-30, 7, 240, 36, 36, 62, 25, 131, 159, 24, 255, 129, 224, 0, 227, 142, 126, 1,
-192, 45, 172, 127, 127, 192, 14, 1, 255, 199, 224, 0, 227, 140, 240, 1, 192,
-26, 88, 115, 127, 224, 14, 57, 221, 207, 0, 0, 227, 13, 192, 1, 192, 34, 68,
-120, 30, 0, 14, 25, 156, 220, 0, 0, 227, 253, 252, 1, 192, 36, 36, 126, 28,
-0, 14, 219, 156, 223, 192, 0, 227, 253, 252, 1, 192, 36, 36, 31, 12, 0, 46,
-27, 140, 223, 192, 0, 227, 141, 193, 193, 192, 40, 20, 7, 140, 0, 206, 25, 140,
-220, 28, 0, 227, 140, 225, 129, 199, 24, 24, 99, 156, 1, 14, 25, 204, 206, 24,
-0, 227, 142, 127, 1, 195, 39, 228, 255, 156, 2, 14, 24, 237, 199, 240, 1, 247,
-222, 62, 1, 198, 44, 44, 223, 30, 2, 31, 28, 237, 131, 224, 1, 224, 0, 0, 3,
-254, 27, 216, 0, 0, 4, 30, 0, 0, 0, 0, 3, 192, 0, 0, 7, 252, 0, 0, 0, 0, 4,
-60, 1, 249, 240, 0, 0, 0, 0, 0, 0, 56, 0, 0, 0, 0, 4, 0, 97, 240, 56, 0, 0,
-0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 1, 224, 28, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-4, 0, 47, 192, 30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 32, 255, 128, 63, 128,
-0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 32, 255, 0, 48, 78, 0, 0, 0, 0, 0, 0, 0, 0,
-0, 0, 15, 176, 255, 0, 112, 49, 0, 0, 0, 0, 0, 0, 0, 0, 0, 28, 8, 56, 255, 0,
-96, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 98, 8, 60, 255, 0, 224, 0, 0, 0, 0, 0, 0,
-0, 0, 0, 0, 130, 56, 126, 255, 3, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 192,
-62, 255, 15, 224, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 14, 191, 255, 192, 0,
-0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 6, 129, 255, 192, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-1, 0, 0, 6, 0, 255, 192, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 7, 128, 63, 192,
-1, 0, 96, 1, 224, 1, 0, 0, 0, 2, 0, 0, 7, 0, 31, 192, 0, 0, 95, 1, 11, 68, 88,
-0, 0, 4, 0, 0, 7, 128, 31, 192, 0, 1, 192, 129, 204, 85, 100, 0, 0, 8, 0, 0,
-15, 128, 63, 224, 0, 0, 95, 1, 8, 85, 68, 0, 1, 144, 0, 0, 31, 128, 143, 224,
-64, 0, 96, 1, 232, 41, 68, 0, 2, 96, 0, 31, 255, 129, 7, 248, 96, 0, 0, 0, 0,
-0, 0, 0, 4, 0, 0, 96, 254, 129, 7, 254, 96, 0, 0, 0, 0, 0, 0, 0, 4, 0, 1, 128,
-254, 131, 135, 255, 224, 0, 0, 1, 192, 64, 16, 0, 8, 0, 7, 0, 254, 131, 255,
-63, 224, 0, 0, 1, 38, 113, 208, 0, 8, 0, 13, 0, 222, 147, 254, 31, 224, 0, 0,
-1, 41, 74, 80, 0, 8, 0, 25, 0, 222, 67, 254, 31, 160, 0, 0, 1, 41, 74, 80, 0,
-12, 0, 49, 0, 222, 19, 254, 62, 48, 0, 0, 1, 198, 113, 208, 0, 2, 0, 32, 128,
-222, 195, 255, 252, 56, 0, 0, 0, 0, 0, 0, 0, 2, 0, 124, 64, 220, 151, 135, 248,
-127, 0, 0, 0, 0, 0, 0, 0, 2, 0, 66, 32, 221, 223, 7, 240, 255, 0, 0, 0, 0, 0,
-0, 0, 2, 0, 129, 23, 93, 159, 15, 241, 131, 0, 0, 0, 0, 0, 0, 0, 4, 0, 128,
-136, 217, 95, 3, 226, 9, 0, 0, 1, 240, 0, 0, 0, 4, 0, 128, 72, 89, 95, 129,
-228, 18, 0, 0, 0, 0, 0, 0, 0, 4, 1, 0, 72, 73, 127, 128, 224, 36, 0, 0, 0, 0,
-0, 0, 0, 28, 1, 0, 76, 129, 127, 192, 96, 8, 0, 0, 0, 0, 0, 0, 0, 16, 1, 0,
-231, 203, 124, 96, 64, 0, 0, 0, 0, 0, 0, 0, 0, 16, 1, 1, 28, 123, 240, 12, 64,
-1, 0, 0, 0, 0, 0, 0, 0, 16, 1, 2, 28, 143, 128, 15, 192, 7, 0, 0, 0, 0, 0, 0,
-0, 16, 1, 4, 17, 143, 24, 15, 192, 14, 0, 0, 0, 0, 0, 0, 0, 28, 1, 4, 1, 135,
-24, 31, 192, 24, 0, 0, 0, 0, 0, 0, 0, 18, 1, 62, 1, 135, 248, 63, 224, 192,
-0, 0, 0, 0, 0, 0, 0, 35, 1, 195, 1, 135, 128, 254, 126, 1, 0, 0, 0, 0, 0, 0,
-0, 35, 193, 131, 195, 135, 255, 248, 112, 1, 0, 0, 0, 0, 0, 0, 0, 67, 241, 131,
-14, 207, 255, 192, 224, 3, 0, 0, 0, 0, 0, 0, 3, 67, 15, 143, 56, 255, 7, 1,
-224, 7, 0, 0, 0, 0, 0, 0, 28, 130, 7, 255, 112, 204, 7, 131, 224, 31, 0, 0,
-0, 0, 0, 0, 32, 134, 30, 29, 120, 156, 7, 255, 224, 127, 0, 0, 0, 0, 0, 63,
-197, 206, 60, 56, 192, 248, 15, 255, 248, 255, 0, 0, 0, 0, 0, 120, 5, 227, 248,
-56, 195, 248, 127, 191, 254, 63, 0, 0, 0, 0, 7, 254, 255, 193, 255, 15, 193,
-255, 15, 31, 252, 31 };
-*/
-
 /*
 	bitmap_test()
 	Displays various bitmaps to ensure bopti is working correctly.
 */
 void bitmap_test(void)
 {
-	extern Image binary_resources_bitmap_opt_start;
-	extern Image binary_resources_symbol_start;
-	extern Image binary_resources_symbol2_start;
-	extern Image binary_resources_sprites_start;
+	extern Image res_bitmap_opt_start;
+	extern Image res_symbol_start;
+	extern Image res_symbol2_start;
+	extern Image res_sprites_start;
+	extern Image res_swords_start;
 
-	Image *opt	= &binary_resources_bitmap_opt_start;
-	Image *sprites	= &binary_resources_sprites_start;
-	Image *sybl	= &binary_resources_symbol_start;
-	Image *sybl2	= &binary_resources_symbol2_start;
+	Image *opt	= &res_bitmap_opt_start;
+	Image *sybl	= &res_symbol_start;
+	Image *sybl2	= &res_symbol2_start;
+	Image *sprites	= &res_sprites_start;
+	Image *swords	= &res_swords_start;
 
-//	enum BlendingMode blend = Blend_Or;
 	uint32_t a32 = 0xffffffff;
-	int black_bg = 0;
+	int black_bg = 0, gray = 0;
 	int key;
+	int x = 20, y = 10;
 
 	while(1)
 	{
-		dclear();
+		if(gray)
+		{
+			gray_start();
+			gclear();
 
-		if(black_bg) dreverse_area(0, 0, 127, 63);
-		dimage(opt, 0, 57);
+			if(black_bg) greverse_area(0, 0, 127, 63);
+			gimage(opt, 0, 57);
 
-		dimage(sprites, 2 & a32, 2);
-		dimage(sybl, 30 & a32, 40);
-		dimage(sybl2, 62 & a32, 40);
+			gimage(sprites, x, y);
+			gimage(swords, x, y + 35);
 
-		dupdate();
+			gupdate();
+		}
+		else
+		{
+			gray_stop();
+			dclear();
+
+			if(black_bg) dreverse_area(0, 0, 127, 63);
+			dimage(opt, 0, 57);
+
+			dimage(sybl, 30 & a32, 40);
+			dimage(sybl2, 62 & a32, 40);
+
+			dupdate();
+
+		}
 
 		key = getkey();
 		if(key == KEY_EXIT) break;
 
-/*
-		if(key == KEY_F1) blend = Blend_Or;
-		if(key == KEY_F2) blend = Blend_And;
-		if(key == KEY_F3) blend = Blend_Invert;
-*/
+		if(key == KEY_F1) gray = !gray;
+		if(key == KEY_F2) a32 ^= 31;
+		if(key == KEY_F3) black_bg = !black_bg;
 
-		if(key == KEY_F4) black_bg = !black_bg;
-		if(key == KEY_F5) a32 ^= 31;
+		if(key == KEY_UP) y--;
+		if(key == KEY_DOWN) y++;
+		if(key == KEY_LEFT) x--;
+		if(key == KEY_RIGHT) x++;
 	}
 
+	gray_stop();
 	return;
 }
 
@@ -256,10 +239,10 @@ void bitmap_test(void)
 
 void text_test(void)
 {
-	extern Font binary_resources_font_start;
-	Font *font = &binary_resources_font_start;
+	extern Font res_font_start;
+	Font *font = &res_font_start;
 
-	print_configure(font);
+	text_configure(font);
 
 	dclear();
 
@@ -284,31 +267,89 @@ void text_test(void)
 
 void gray_test(void)
 {
-	extern Image binary_resources_illustration_start;
-	Image *illustration = &binary_resources_illustration_start;
+	extern Image res_illustration_start;
+	Image *illustration = &res_illustration_start;
 
-	int light, dark;
-	int key;
+	int *v1, *v2;
 
-	gray_getDelays(&light, &dark);
+	int delays[2]; // { light, dark }
+	int key, changed = 1, i;
+	int selected = 0;
+
+	gray_getDelays(delays, delays + 1);
 	gray_start();
 
 	while(1)
 	{
-		gclear();
-		dimage(illustration, 0, 0);
-		gclear_area(64, 0, 127, 63);
-//		gupdate();
+		if(changed)
+		{
+			gray_setDelays(delays[0], delays[1]);
+			gclear();
 
-		key = getkey();
+			v1 = gray_lightVRAM();
+			v2 = gray_darkVRAM();
+
+			for(i = 0; i < 63; i++)
+			{
+				v1[(i << 2)] = v1[(i << 2) + 1] =
+					-((i & 31) < 16);
+				v2[(i << 2)] = v2[(i << 2) + 1] =
+					-(i < 32);
+			}
+
+//			gimage(illustration, 0, 0);
+//			gclear_area(64, 0, 127, 63);
+
+			gtext("light", 78, 6);
+			print_int(delays[0], 103, 6);
+
+			gtext("dark", 78, 15);
+			print_int(delays[1], 103, 15);
+
+			gtext(">", 70, selected ? 15 : 6);
+			gupdate();
+		}
+
+		changed = 0;
+
+		key = getkey_opt(Getkey_RepeatArrowKeys, 1);
 		if(key == KEY_EXIT) break;
-/*
-		if(key == KEY_F1) gray_setDelays(--light, dark);
-		if(key == KEY_F2) gray_setDelays(++light, dark);
 
-		if(key == KEY_F5) gray_setDelays(light, --dark);
-		if(key == KEY_F6) gray_setDelays(light, ++dark);
-*/
+		changed = 1;
+
+		switch(key)
+		{
+		case KEY_F1:
+			delays[0] = 860;
+			delays[1] = 1298;
+			break;
+		case KEY_F2:
+			delays[0] = 912;
+			delays[1] = 1343;
+			break;
+		case KEY_F3:
+			delays[0] = 993;
+			delays[1] = 1609;
+			break;
+		case KEY_F6:
+			selected = !selected;
+			break;
+		case KEY_UP:
+			delays[selected] += 10;
+			break;
+		case KEY_DOWN:
+			if(delays[selected] >= 110) delays[selected] -= 10;
+			break;
+		case KEY_RIGHT:
+			delays[selected]++;
+			break;
+		case KEY_LEFT:
+			if(delays[selected] >= 101) delays[selected]--;
+			break;
+		default:
+			changed = 0;
+			break;
+		}
 	}
 
 	gray_stop();
@@ -322,6 +363,7 @@ void gray_test(void)
 */
 int main_menu(void)
 {
+	extern unsigned int bgint, egint;
 	const char *mpu_names[] = {
 		"MPU_Unkown",
 		"MPU_SH7337",
@@ -358,11 +400,158 @@ int main_menu(void)
 		if(key == KEY_2) return 2;
 		if(key == KEY_3) return 3;
 		if(key == KEY_4) return 4;
+		if(key == KEY_5) return 5;
 	}
 
 	return 0;
 }
 
+static const unsigned char screen[1024] = {
+0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+0, 0, 0, 0, 0, 0, 0, 7, 159, 0, 0, 1, 192, 0, 0, 0, 0, 0, 121, 240, 0, 0, 0,
+31, 191, 192, 0, 3, 224, 27, 216, 0, 0, 1, 251, 252, 0, 0, 0, 57, 247, 222,
+30, 7, 240, 36, 36, 62, 25, 131, 159, 24, 255, 129, 224, 0, 227, 142, 126, 1,
+192, 45, 172, 127, 127, 192, 14, 1, 255, 199, 224, 0, 227, 140, 240, 1, 192,
+26, 88, 115, 127, 224, 14, 57, 221, 207, 0, 0, 227, 13, 192, 1, 192, 34, 68,
+120, 30, 0, 14, 25, 156, 220, 0, 0, 227, 253, 252, 1, 192, 36, 36, 126, 28,
+0, 14, 219, 156, 223, 192, 0, 227, 253, 252, 1, 192, 36, 36, 31, 12, 0, 46,
+27, 140, 223, 192, 0, 227, 141, 193, 193, 192, 40, 20, 7, 140, 0, 206, 25, 140,
+220, 28, 0, 227, 140, 225, 129, 199, 24, 24, 99, 156, 1, 14, 25, 204, 206, 24,
+0, 227, 142, 127, 1, 195, 39, 228, 255, 156, 2, 14, 24, 237, 199, 240, 1, 247,
+222, 62, 1, 198, 44, 44, 223, 30, 2, 31, 28, 237, 131, 224, 1, 224, 0, 0, 3,
+254, 27, 216, 0, 0, 4, 30, 0, 0, 0, 0, 3, 192, 0, 0, 7, 252, 0, 0, 0, 0, 4,
+60, 1, 249, 240, 0, 0, 0, 0, 0, 0, 56, 0, 0, 0, 0, 4, 0, 97, 240, 56, 0, 0,
+0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 1, 224, 28, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+4, 0, 47, 192, 30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 32, 255, 128, 63, 128,
+0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 32, 255, 0, 48, 78, 0, 0, 0, 0, 0, 0, 0, 0,
+0, 0, 15, 176, 255, 0, 112, 49, 0, 0, 0, 0, 0, 0, 0, 0, 0, 28, 8, 56, 255, 0,
+96, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 98, 8, 60, 255, 0, 224, 0, 0, 0, 0, 0, 0,
+0, 0, 0, 0, 130, 56, 126, 255, 3, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 192,
+62, 255, 15, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 14, 191, 255, 192, 0,
+0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 6, 129, 255, 192, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+1, 0, 0, 6, 0, 255, 192, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 7, 128, 63, 192,
+0, 0, 96, 1, 224, 1, 0, 0, 0, 2, 0, 0, 7, 0, 31, 192, 0, 0, 95, 1, 11, 68, 88,
+0, 0, 4, 0, 0, 7, 128, 31, 192, 0, 1, 192, 129, 204, 85, 100, 0, 0, 8, 0, 0,
+15, 128, 63, 224, 0, 0, 95, 1, 8, 85, 68, 0, 1, 144, 0, 0, 31, 128, 143, 224,
+64, 0, 96, 1, 232, 41, 68, 0, 2, 96, 0, 31, 255, 129, 7, 248, 96, 0, 0, 0, 0,
+0, 0, 0, 4, 0, 0, 96, 254, 129, 7, 254, 96, 0, 0, 0, 0, 0, 0, 0, 4, 0, 1, 128,
+254, 131, 135, 255, 224, 0, 0, 1, 192, 64, 16, 0, 8, 0, 7, 0, 254, 131, 255,
+63, 224, 0, 0, 1, 38, 113, 208, 0, 8, 0, 13, 0, 222, 147, 254, 31, 224, 0, 0,
+1, 41, 74, 80, 0, 8, 0, 25, 0, 222, 67, 254, 31, 160, 0, 0, 1, 41, 74, 80, 0,
+12, 0, 49, 0, 222, 19, 254, 62, 48, 0, 0, 1, 198, 113, 208, 0, 2, 0, 32, 128,
+222, 195, 255, 252, 56, 0, 0, 0, 0, 0, 0, 0, 2, 0, 124, 64, 220, 151, 135, 248,
+127, 0, 0, 0, 0, 0, 0, 0, 2, 0, 66, 32, 221, 223, 7, 240, 255, 0, 0, 0, 0, 0,
+0, 0, 2, 0, 129, 23, 93, 159, 15, 241, 131, 0, 0, 0, 0, 0, 0, 0, 4, 0, 128,
+136, 217, 95, 3, 226, 9, 0, 0, 1, 240, 0, 0, 0, 4, 0, 128, 72, 89, 95, 129,
+228, 18, 0, 0, 0, 0, 0, 0, 0, 4, 1, 0, 72, 73, 127, 128, 224, 36, 0, 0, 0, 0,
+0, 0, 0, 28, 1, 0, 76, 129, 127, 192, 96, 8, 0, 0, 0, 0, 0, 0, 0, 16, 1, 0,
+231, 203, 124, 96, 64, 0, 0, 0, 0, 0, 0, 0, 0, 16, 1, 1, 28, 123, 240, 12, 64,
+1, 0, 0, 0, 0, 0, 0, 0, 16, 1, 2, 28, 143, 128, 15, 192, 7, 0, 0, 0, 0, 0, 0,
+0, 16, 1, 4, 17, 143, 24, 15, 192, 14, 0, 0, 0, 0, 0, 0, 0, 28, 1, 4, 1, 135,
+24, 31, 192, 24, 0, 0, 0, 0, 0, 0, 0, 18, 1, 62, 1, 135, 248, 63, 224, 192,
+0, 0, 0, 0, 0, 0, 0, 35, 1, 195, 1, 135, 128, 254, 126, 1, 0, 0, 0, 0, 0, 0,
+0, 35, 193, 131, 195, 135, 255, 248, 112, 1, 0, 0, 0, 0, 0, 0, 0, 67, 241, 131,
+14, 207, 255, 192, 224, 3, 0, 0, 0, 0, 0, 0, 3, 67, 15, 143, 56, 255, 7, 1,
+224, 7, 0, 0, 0, 0, 0, 0, 28, 130, 7, 255, 112, 204, 7, 131, 224, 31, 0, 0,
+0, 0, 0, 0, 32, 134, 30, 29, 120, 156, 7, 255, 224, 127, 0, 0, 0, 0, 0, 63,
+197, 206, 60, 56, 192, 248, 15, 255, 248, 255, 0, 0, 0, 0, 0, 120, 5, 227, 248,
+56, 195, 248, 127, 191, 254, 63, 0, 0, 0, 0, 7, 254, 255, 193, 255, 15, 193,
+255, 15, 31, 252, 31 };
+
+void ML_bmp_or_cl(const unsigned char *bmp, int x, int y, int width, int height)
+{
+	unsigned short line;
+	char shift, *screen, *p;
+	int i, j, real_width, begin_x, end_x, begin_y, end_y;
+	char bool1=1, bool2=1, bool3;
+	if(!bmp || x<1-width || x>127 || y<1-height || y>63 || height<1 || width<1) return;
+	p = (char*)&line;
+	real_width = (width-1>>3<<3)+8;
+	if(y < 0) begin_y = -y;
+	else begin_y = 0;
+	if(y+height > 64) end_y = 64-y;
+	else end_y = height;
+	shift = 8-(x&7);
+	if(x<0)
+	{
+		begin_x = -x>>3;
+		if(shift != 8) bool1 = 0;
+	} else begin_x = 0;
+	if(x+real_width > 128) end_x = 15-(x>>3), bool2 = 0;
+	else end_x = real_width-1>>3;
+	bool3 = (end_x == real_width-1>>3);
+	screen = display_getCurrentVRAM()+(y+begin_y<<4)+(x>>3);
+
+	for(i=begin_y ; i<end_y ; i++)
+	{
+		if(begin_x < end_x)
+		{
+			line = bmp[i*(real_width>>3)+begin_x] << shift;
+			if(bool1) screen[begin_x] |= *p;
+			if(shift!=8) screen[begin_x+1] |= *(p+1);
+			for(j=begin_x+1 ; j<end_x ; j++)
+			{
+				line = bmp[i*(real_width>>3)+j] << shift;
+				screen[j] |= *p;
+				if(shift!=8) screen[j+1] |= *(p+1);
+			}
+		}
+		line = bmp[i*(real_width>>3)+end_x];
+		if(bool3) line &= -1<<real_width-width;
+		line <<= shift;
+		if(begin_x < end_x || bool1) screen[end_x] |= *p;
+		if(bool2) screen[end_x+1] |= *(p+1);
+		screen += 16;
+	}
+}
+
+#include <../src/timer/timer_internals.h>
+void debug(void)
+{
+	extern Image res_screen_start;
+	struct mod_tmu *timer;
+	int time1, time2;
+	int i;
+
+	timer_get(TIMER_USER, &timer, NULL);
+
+	dclear();
+	ML_bmp_or_cl(screen, 1, 1, 128, 64);
+	dupdate();
+	getkey();
+
+	dclear();
+	dimage(&res_screen_start, 1, 1);
+	dupdate();
+	getkey();
+
+	dclear();
+	dtext("ML...", 2, 2);
+	dupdate();
+
+	timer_start(TIMER_USER, 0x0fffffff, TIMER_Po_4, NULL, 0);
+	for(i = 0; i < 1000; i++) ML_bmp_or_cl(screen, 1, 1, 128, 64);
+	time1 = timer->TCNT;
+	timer_stop(TIMER_USER);
+	time1 = 0x0fffffff - time1;
+
+	dclear();
+	dtext("gint...", 2, 2);
+	dupdate();
+
+	timer_start(TIMER_USER, 0x0fffffff, TIMER_Po_4, NULL, 0);
+	for(i = 0; i < 1000; i++) dimage(&res_screen_start, 1, 1);
+	time2 = timer->TCNT;
+	timer_stop(TIMER_USER);
+	time2 = 0x0fffffff - time2;
+
+	dclear();
+	print_hex(time1, 2, 2);
+	print_hex(time2, 2, 9);
+	dupdate();
+	while(getkey() != KEY_EXIT);
+}
+
 /*
 	main()
 	Handles application calls.
@@ -371,10 +560,10 @@ int main_menu(void)
 */
 int main(void)
 {
-	extern Font binary_resources_font_start;
-	Font *font = &binary_resources_font_start;
+	extern Font res_font_start;
+	Font *font = &res_font_start;
 
-	print_configure(font);
+	text_configure(font);
 
 	int app;
 
@@ -387,6 +576,7 @@ int main(void)
 		if(app == 2) bitmap_test();
 		if(app == 3) text_test();
 		if(app == 4) gray_test();
+		if(app == 5) debug();
 	}
 
 	return 0;
diff --git a/demo/resources/bitmap_opt.bmp b/demo/resources/bitmap_opt.bmp
index 66fe722..dd8d123 100644
Binary files a/demo/resources/bitmap_opt.bmp and b/demo/resources/bitmap_opt.bmp differ
diff --git a/demo/resources/screen.bmp b/demo/resources/screen.bmp
new file mode 100644
index 0000000..050825a
Binary files /dev/null and b/demo/resources/screen.bmp differ
diff --git a/gintdemo.g1a b/gintdemo.g1a
new file mode 100644
index 0000000..ec073c9
Binary files /dev/null and b/gintdemo.g1a differ
diff --git a/include/7305.h b/include/7305.h
index f6ff1a3..1eb7e71 100644
--- a/include/7305.h
+++ b/include/7305.h
@@ -62,7 +62,7 @@ struct _st_rtc
 	gap(1);
 
 	union {
-		unsigned char;
+		unsigned char BYTE;
 		struct {
 			unsigned		:2;
 			unsigned TENS		:2;
@@ -208,7 +208,7 @@ struct _st_rtc
 		struct {
 			unsigned ENB		:1;
 			unsigned		:7;
-		}
+		};
 	} RCR3;
 
 } __attribute__((packed));
diff --git a/include/display.h b/include/display.h
index afca785..4cca184 100644
--- a/include/display.h
+++ b/include/display.h
@@ -14,6 +14,7 @@
 //	Heading declarations.
 //---
 
+#include <stdint.h>
 #include <tales.h>
 
 enum Color
@@ -150,4 +151,45 @@ void dimage(struct Image *image, int x, int y);
 
 
 
+//---
+//	Rectangle masks.
+//
+//	The concept of 'rectangle masks' is used several times in this module.
+//	It is based on the fact that an operation that affects a rectangle acts
+//	the same on all its lines. Therefore the behavior of the operation is
+//	determined by its behavior on a single line, which is represented using
+//	'masks' whose bits indicate whether a pixel is affected (1) or not (0).
+//
+//	For example when clearing the screen rectangle (16, 16, 112, 48), the
+//	masks will represent information '16 to 112 on x-axis', and will hold
+//	the following values : 0000ffff, ffffffff, ffffffff and ffff0000. These
+//	masks can then be used by setting vram[offset] &= ~masks[i]. This
+//	appears to be very flexible : for instance, vram[offset] ^= masks[i]
+//	will reverse the pixels in the same rectangle.
+//
+//	This technique can also be used in more subtle cases with more complex
+//	patterns, but within this module it is unlikely to happen.
+//
+//---
+
+/*
+	adjustRectangle()
+	Adjusts the given rectangle coordinates to ensure that :
+	- the rectangle is entirely contained in the screen
+	- x1 < x2
+	- y1 < y2
+	which is needed when working with screen rectangles.
+*/
+void adjustRectangle(int *x1, int *y1, int *x2, int *y2);
+
+/*
+	getMasks()
+	Computes the rectangle masks needed to affect pixels located between x1
+	and x2 (both included). The four masks are stored in the third argument
+	(seen as an array).
+*/
+void getMasks(int x1, int x2, uint32_t *masks);
+
+
+
 #endif	// _DISPLAY_H
diff --git a/include/gray.h b/include/gray.h
index 94653ac..de14fba 100644
--- a/include/gray.h
+++ b/include/gray.h
@@ -60,6 +60,16 @@ void gray_getDelays(int *light, int *dark);
 	Finding values that give proper grays is quite the hard part of the
 	gray engine. Usual values are about 1000, with light being between 75
 	and 90% of dark.
+
+	Typical values:
+
+	values		stability	stripes		colors
+	---------------------------------------------------------
+	860, 1298	excellent	worst static	good
+	912, 1343	bad		none		very good
+	993, 1609	medium		light fast	good       (default)
+	---------------------------------------------------------
+
 */
 void gray_setDelays(int light, int dark);
 
diff --git a/include/setjmp.h b/include/setjmp.h
index 2037b5e..0addccf 100644
--- a/include/setjmp.h
+++ b/include/setjmp.h
@@ -14,17 +14,12 @@ typedef	unsigned int jmp_buf[16];
 /*
 	setjmp()
 	Configures a jump by saving data to the given jump buffer.
-
-	@arg	env	Empty jump buffer.
 */
 int setjmp(jmp_buf env);
 
 /*
 	longjmp()
 	Performs a long jump.
-
-	@arg	env	Jump buffer configure with setjmp().
-	@arg	value	setjmp() will return this integer after the jump.
 */
 void longjmp(jmp_buf env, int value);
 
diff --git a/include/stdlib.h b/include/stdlib.h
index de053e8..0a0ff01 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -34,15 +34,15 @@ void exit(int status);
 
 /*
 	malloc()
-	Allocs 'size' bytes and returns a pointer to a free memory area.
+	Allocates 'size' bytes and returns a pointer to a free memory area.
 	Returns NULL on error.
 */
 void *malloc(size_t size);
 
 /*
 	calloc()
-	Allocs 'n' elements of size 'size' and wipes the memory area. Returns
-	NULL on error.
+	Allocates 'n' elements of size 'size' and wipes the memory area.
+	Returns NULL on error.
 */
 void *calloc(size_t n, size_t size);
 
diff --git a/include/string.h b/include/string.h
index d74977a..d5c96dc 100644
--- a/include/string.h
+++ b/include/string.h
@@ -12,20 +12,12 @@
 	Copies a memory area. The two areas must not overlap (if they do, use
 	memmove()). A smart copy is performed when possible. To enhance
 	performance, make sure than destination and source are both 4-aligned.
-
-	@arg	destination
-	@arg	source
-	@arg	byte_number
 */
 void *memcpy(void *destination, const void *source, size_t byte_number);
 
 /*
 	memset()
 	Sets the contents of a memory area. A smart copy is performed.
-
-	@arg	area
-	@arg	byte		Byte to write in the area.
-	@arg	byte_number
 */
 void *memset(void *destination, int byte, size_t byte_number);
 
diff --git a/info b/info
deleted file mode 100644
index 8a2dc33..0000000
--- a/info
+++ /dev/null
@@ -1,16 +0,0 @@
-
-Experimental power reduction as function of the keyboard analysis frequency. 
-
-SH3
-      None	   0 %
-      4 Hz	 2.8 %
-     16 Hz	 2.8 %
-     64 Hz	 2.8 %
-    256 Hz	20.0 %
-
-SH4
-      None	   0 %
-      4 Hz	 1.8 %
-     16 Hz	 1.8 %
-     64 Hz	 1.8 %
-    256 Hz	 3.6 %
diff --git a/libc.a b/libc.a
index 29ad94c..587b56e 100644
Binary files a/libc.a and b/libc.a differ
diff --git a/libgint.a b/libgint.a
index 3c26fd7..30b9985 100644
Binary files a/libgint.a and b/libgint.a differ
diff --git a/src/bopti/bopti_internals.c b/src/bopti/bopti_internals.c
index b258e23..90f3601 100644
--- a/src/bopti/bopti_internals.c
+++ b/src/bopti/bopti_internals.c
@@ -1,18 +1,22 @@
 #include <bopti_internals.h>
 
+// Monochrome video ram, light and dark buffers (in this order).
+int *vram, *v1, *v2;
+
 /*
 	bopti_op()
 	Operates on a vram long. The operator will often not contain 32 bits of
 	image information. Since neutral bits are not the same for all
-	operations, the op_mask argument indicates which bits should be used
-	for the operation. Which operation has to be done is determined by the
-	channel setting.
+	operations, a mask is used to indicate which bits should be used for
+	the operation. This mask is taken for the image's rectangle masks (see
+	module display for more information on rectangle masks).
+	Which operation is performed is determined by the channel setting.
 */
-static void bopti_op_mono(int offset, uint32_t operator, uint32_t op_mask)
+void bopti_op_mono(int offset, uint32_t operator, struct Command *c)
 {
-	operator &= op_mask;
+	operator &= c->masks[offset & 3];
 
-	switch(channel)
+	switch(c->channel)
 	{
 	case Channel_Mono:
 		vram[offset] |= operator;
@@ -26,11 +30,11 @@ static void bopti_op_mono(int offset, uint32_t operator, uint32_t op_mask)
 		break;
 	}
 }
-static void bopti_op_gray(int offset, uint32_t operator, uint32_t op_mask)
+void bopti_op_gray(int offset, uint32_t operator, struct Command *c)
 {
-	operator &= op_mask;
+	operator &= c->masks[offset & 3];
 
-	switch(channel)
+	switch(c->channel)
 	{
 	case Channel_Mono:
 		v1[offset] |= operator;
@@ -66,74 +70,75 @@ static void bopti_op_gray(int offset, uint32_t operator, uint32_t op_mask)
 	because bopti_grid() will perform a 32-bit shift when x is a multiple
 	of 32, which is undefined behavior.
 */
-static void bopti_grid_a32(const uint32_t *layer, int x, int y,
-	int column_count)
+void bopti_grid_a32(const uint32_t *layer, int column_count, int height,
+	struct Command *c)
 {
-	int vram_column_offset = (y << 2) + (x >> 5);
+	int vram_column_offset = (c->y << 2) + (c->x >> 5);
 	int vram_offset = vram_column_offset;
 	int column, row;
 
 	for(column = 0; column < column_count; column++)
 	{
-		for(row = 0; row < height; row++)
+		for(row = c->top; row < c->bottom; row++)
 		{
-			(*op)(vram_offset, *layer, 0xffffffff);
-			layer++;
+			(*c->op)(vram_offset, layer[row], c);
 			vram_offset += 4;
 		}
 
 		vram_column_offset++;
 		vram_offset = vram_column_offset;
+		layer += height;
 	}
 }
-static void bopti_grid(const uint32_t *layer, int x, int y, int column_count)
+void bopti_grid(const uint32_t *layer, int column_count, int height,
+	struct Command *c)
 {
 	if(!column_count) return;
-	if(!(x & 31))
+	if(!(c->x & 31))
 	{
-		bopti_grid_a32(layer, x, y, column_count);
+		bopti_grid_a32(layer, column_count, height, c);
 		return;
 	}
 
 	const uint32_t *p1, *p2;
-	uint32_t l1, l2;
+	uint32_t l1, l2, operator;
 	int right_column, line;
 
-	int vram_column_offset = (y << 2) + (x >> 5);
+	int vram_column_offset = (c->y << 2) + (c->x >> 5) + (c->x < 0);
 	int vram_offset = vram_column_offset;
 
-	int shift1 = 32 - (x & 31);
-	int shift2 = (x & 31);
+	int shift1 = 32 - (c->x & 31);
+	int shift2 = (c->x & 31);
 
-	uint32_t operator, and_mask;
-	uint32_t and_mask_0 = 0xffffffff >> shift2;
-	uint32_t and_mask_1 = 0xffffffff << shift1;
-
-	// Initializing two pointers. Since the columns are written one after
-	// another, they will be updated directly to parse the whole grid.
+	// Initializing two pointers. They will read two adjacent columns at
+	// the same time (p2 is column ahead of p1). Since the columns are
+	// written one after another, incrementing them will suffice when
+	// reaching the end of two columns, to move them to the next ones.
 	p1 = layer - height;
 	p2 = layer;
 
-	// Drawing vram longwords, using pairs of columns.
-	for(right_column = 0; right_column <= column_count; right_column++)
-	{
-		and_mask = 0xffffffff;
-		if(right_column == 0)			and_mask &= and_mask_0;
-		if(right_column == column_count)	and_mask &= and_mask_1;
+	// We don't want to write the first vram column when x is negative.
+	if(c->x < 0) p1 += height, p2 += height;
+	right_column = (c->x < 0);
 
-		for(line = 0; line < height; line++)
+	// Drawing vram longwords, using pairs of columns.
+	while(right_column <= column_count)
+	{
+		for(line = c->top; line < c->bottom; line++)
 		{
-			l1 = (right_column > 0) ? (*p1) : (0);
-			l2 = (right_column < column_count) ? (*p2) : (0);
-			p1++, p2++;
+			l1 = (right_column > 0) ? p1[line] : (0);
+			l2 = (right_column < column_count) ? p2[line] : (0);
 
 			operator = (l1 << shift1) | (l2 >> shift2);
-			(*op)(vram_offset, operator, and_mask);
+			(*c->op)(vram_offset, operator, c);
 			vram_offset += 4;
 		}
 
+		p1 += height;
+		p2 += height;
 		vram_column_offset++;
 		vram_offset = vram_column_offset;
+		right_column++;
 	}
 }
 
@@ -144,13 +149,13 @@ static void bopti_grid(const uint32_t *layer, int x, int y, int column_count)
 	is read and updated so that it points to the next line at the end of
 	the operation.
 */
-static uint32_t bopti_end_get1(const unsigned char **data)
+uint32_t bopti_end_get1(const unsigned char **data)
 {
 	uint32_t operator = **data;
 	*data += 1;
 	return operator;
 }
-static uint32_t bopti_end_get2(const unsigned char **data)
+uint32_t bopti_end_get2(const unsigned char **data)
 {
 	uint32_t operator = *((uint16_t *)*data);
 	*data += 2;
@@ -165,63 +170,57 @@ static uint32_t bopti_end_get2(const unsigned char **data)
 	whose with is lower than 32. (Actually is it lower or equal to 16;
 	otherwise it would have been a column and the end would be empty).
 */
-static void bopti_end_nover(const unsigned char *end, int x, int y, int width)
+void bopti_end_nover(const unsigned char *end, int size, struct Command *c)
 {
 	uint32_t (*get)(const unsigned char **data) =
-		(width > 8) ? bopti_end_get2 : bopti_end_get1;
-
-	int vram_offset = (y << 2) + (x >> 5);
-	int row;
+		(size == 2) ? bopti_end_get2 : bopti_end_get1;
 
 	// We *have* shift >= 0 because of this function's 'no overlap'
 	// requirement.
-	int shift_base = (width > 8) ? 16 : 24;
-	int shift = shift_base - (x & 31);
-
-	uint32_t and_mask = (0xffffffff << (32 - width)) >> (x & 31);
+	int shift = (32 - (size << 3)) - (c->x & 31);
+	int vram_offset = (c->y << 2) + (c->x >> 5);
 	uint32_t operator;
+	int row;
 
-	for(row = 0; row < height; row++)
+	// Skipping c->top lines (because get() function only allows sequential
+	// access).
+	end += c->top * size;
+
+	for(row = c->top; row < c->bottom; row++)
 	{
 		operator = (*get)(&end);
 		operator <<= shift;
 
-		(*op)(vram_offset, operator, and_mask);
+		(*c->op)(vram_offset, operator, c);
 		vram_offset += 4;
 	}
 }
-static void bopti_end(const unsigned char *end, int x, int y, int width)
+void bopti_end(const unsigned char *end, int size, struct Command *c)
 {
-	if((x & 31) + width <= 32)
-	{
-		bopti_end_nover(end, x, y, width);
-		return;
-	}
-
 	uint32_t (*get)(const unsigned char **data) =
-		(width > 8) ? (bopti_end_get2) : (bopti_end_get1);
+		(size == 2) ? (bopti_end_get2) : (bopti_end_get1);
 
-	int vram_offset = (y << 2) + (x >> 5);
+	int vram_offset = (c->y << 2) + (c->x >> 5);
+	uint32_t row_data, operator;
 	int row;
 
-	int shift_base = (width > 8) ? 16 : 24;
-	int shift1 = (x & 31) - shift_base;
-	int shift2 = shift_base + 32 - (x & 31);
+	int shift_base = (32 - (size << 3));
+	int shift1 = (c->x & 31) - shift_base;
+	int shift2 = shift_base + 32 - (c-> x & 31);
 
-	uint32_t and_mask_0 = 0xffffffff >> (x & 31);
-	uint32_t and_mask_1 = 0xffffffff << (64 - width - (x & 31));
+	// Skipping c->top lines (because get() function only allows sequential
+	// access).
+	end += c->top * size;
 
-	uint32_t row_data, operator;
-
-	for(row = 0; row < height; row++)
+	for(row = c->top; row < c->bottom; row++)
 	{
 		row_data = (*get)(&end);
 
 		operator = row_data >> shift1;
-		(*op)(vram_offset, operator, and_mask_0);
+		(*c->op)(vram_offset, operator, c);
 
 		operator = row_data << shift2;
-		(*op)(vram_offset + 1, operator, and_mask_1);
+		(*c->op)(vram_offset + 1, operator, c);
 
 		vram_offset += 4;
 	}
@@ -237,41 +236,63 @@ static void bopti_end(const unsigned char *end, int x, int y, int width)
 	bopti()
 	Draws a layer in the video ram.
 */
-static void bopti(const unsigned char *layer, int x, int y, int columns,
-	int end_size)
+void bopti(const unsigned char *layer, struct Structure *s, struct Command *c)
 {
-	const unsigned char *end = layer + ((columns * height) << 2);
-	int end_x = x + (columns << 5);
+	const unsigned char *grid, *end;
+	int grid_columns, has_end;
 
-	bopti_grid((const uint32_t *)layer, x, y, columns);
-	if(end_size) bopti_end(end, end_x, y, end_size);
+	// Skipping columns at the beginning.
+	grid = layer + ((c->left * s->height) << 2);
+
+	// Updating the command arguments to eliminate some information about
+	// parts that are not being drawn.
+	c->x += (c->left << 5);
+	c->y += c->top;
+
+	// Columns are identified by ids 0 to s->columns - 1, and the end has
+	// id s->columns. So the end is drawn if this last column is included.
+	has_end = (c->right == s->columns);
+	// Computing number of grid columns to draw.
+	grid_columns = c->right - c->left + 1 - has_end;
+
+	bopti_grid((const uint32_t *)grid, grid_columns, s->height, c);
+
+	if(has_end)
+	{
+		end = layer + ((s->columns * s->height) << 2);
+		c->x += (grid_columns << 5);
+
+		if((c->x & 31) + s->end_size <= 32)
+			bopti_end_nover(end, s->end_bytes, c);
+		else
+			bopti_end(end, s->end_bytes, c);
+	}
 }
 
 /*
 	getStructure()
 	Determines the image size and data pointer.
 */
-static void getStructure(struct Image *img, int *width, int *height,
-	int *layer_size, const unsigned char **data, int *columns,
-	int *end_size)
+void getStructure(struct Image *img, struct Structure *s)
 {
 	int column_count, end, end_bytes, layer;
 
 	// Large images.
 	if(!img->width && !img->height)
 	{
-		if(width)	*width  = (img->data[0] << 8) | img->data[1];
-		if(height)	*height = (img->data[2] << 8) | img->data[3];
-		if(data)	*data   = img->data + 4;
+		s->width	= (img->data[0] << 8) | img->data[1];
+		s->height	= (img->data[2] << 8) | img->data[3];
+		s->data		= img->data + 4;
 
-		column_count = (*width + 31) >> 5;
-		end = end_bytes = 0;
+		column_count = (s->width + 31) >> 5;
+		end = 0;
+		end_bytes = 0;
 	}
 	else
 	{
-		if(width)	*width  = img->width;
-		if(height)	*height = img->height;
-		if(data)	*data   = img->data;
+		s->width	= img->width;
+		s->height	= img->height;
+		s->data		= img->data;
 
 		column_count = img->width >> 5;
 		end = img->width & 31;
@@ -280,13 +301,21 @@ static void getStructure(struct Image *img, int *width, int *height,
 			end <= 8	? 1 :
 			end <= 16	? 2 :
 			4;
+
+		if(end_bytes == 4)
+		{
+			column_count++;
+			end = 0;
+			end_bytes = 0;
+		}
 	}
 
 	// The layer size must be rounded to a multiple of 4.
 	layer = img->height * ((column_count << 2) + end_bytes);
 	if(layer & 3) layer += 4 - (layer & 3);
 
-	if(columns)	*columns    = column_count;
-	if(end_size)	*end_size   = end;
-	if(layer_size)	*layer_size = layer;
+	s->columns	= column_count;
+	s->end_bytes	= end_bytes;
+	s->end_size	= end;
+	s->layer_size	= layer;
 }
diff --git a/src/bopti/bopti_internals.h b/src/bopti/bopti_internals.h
index 99a40a2..1883613 100644
--- a/src/bopti/bopti_internals.h
+++ b/src/bopti/bopti_internals.h
@@ -18,6 +18,7 @@
 #define	_BOPTI_INTERNALS_H	1
 
 #include <stdint.h>
+#include <display.h>
 
 /*
 	enum Channel
@@ -49,15 +50,43 @@ enum Format
 				  Channel_DarkAlpha
 };
 
-// The following variables refer to parameters that do not change during the
-// drawing operation (at least for the time of a layer). They could be passed
-// on by every function from the module, but this would be heavy and useless.
-// Using global variables is not really a proper solution but it does simplify
-// code much.
+/*
+	struct Structure
+	Describes an image's structure.
+*/
+struct Structure
+{
+	int width, height;
+	int layer_size;
+
+	const unsigned char *data;
+	int columns;
+	int end_size, end_bytes;
+};
+
+/*
+	struct Command
+	Contains a drawing operation's parameters.
+*/
+struct Command
+{
+	// Channel being drawn.
+	enum Channel channel;
+	// Operation used (whether bopti_op_mono() or bopti_op_gray()).
+	void (*op)(int offset, uint32_t operator, struct Command *command);
+	// Portion of the bitmap which is drawn. 'top' and 'bottom' refer to
+	// lines where 'left' and 'right' refer to column ids.
+	int left, right, top, bottom;
+	// Position of the bitmap on the screen.
+	int x, y;
+	// Rectangle masks.
+	uint32_t masks[4];
+};
+
+// The video ram addresses are set by the public functions and used internally
+// by the module.
+// Monochrome video ram, light and dark buffers (in this order).
 extern int *vram, *v1, *v2;
-extern enum Channel channel;
-extern int height;
-extern void (*op)(int offset, uint32_t operator, uint32_t op_mask);
 
 
 
@@ -69,12 +98,13 @@ extern void (*op)(int offset, uint32_t operator, uint32_t op_mask);
 	bopti_op()
 	Operates on a vram long. The operator will often not contain 32 bits of
 	image information. Since neutral bits are not the same for all
-	operations, the op_mask argument indicates which bits should be used
-	for the operation. Which operation has to be done is determined by the
-	channel setting.
+	operations, a mask is used to indicate which bits should be used for
+	the operation. This mask is taken for the image's rectangle masks (see
+	module display for more information on rectangle masks).
+	Which operation is performed is determined by the channel setting.
 */
-void bopti_op_mono(int offset, uint32_t operator, uint32_t op_mask);
-void bopti_op_gray(int offset, uint32_t operator, uint32_t op_mask);
+void bopti_op_mono(int offset, uint32_t operator, struct Command *c);
+void bopti_op_gray(int offset, uint32_t operator, struct Command *c);
 
 /*
 	bopti_grid()		-- general form
@@ -85,10 +115,12 @@ void bopti_op_gray(int offset, uint32_t operator, uint32_t op_mask);
 	The need for bopti_grid_a32() is not only linked to optimization,
 	because bopti_grid() will perform a 32-bit shift when x is a multiple
 	of 32, which is undefined behavior.
+	bopti_grid() calls bopti_grid_32() by default.
 */
-void bopti_grid_a32(const uint32_t *layer, int x, int y, int column_count);
-void bopti_grid(const uint32_t *layer, int x, int y, int column_count);
-
+void bopti_grid_a32(const uint32_t *layer, int columns, int height,
+	struct Command *c);
+void bopti_grid(const uint32_t *layer, int columns, int height,
+	struct Command *c);
 /*
 	bopti_end_get()
 	Returns an operator for the end of a line, whose width is lower than 32
@@ -105,23 +137,24 @@ uint32_t bopti_end_get2(const unsigned char **data);
 
 	Draws the end of a layer, which can be considered as a whole layer
 	whose with is lower than 32. (Actually is it lower or equal to 16;
-	otherwise it would have been a column and the end would be empty).
+	otherwise it would have been a column and the end would be empty). The
+	'size' arguments is in bytes.
+	Unlike bopti_grid_a32(), bopti_end_nover() is not called automatically
+	by bopti_end().
 */
-void bopti_end_nover(const unsigned char *end, int x, int y, int width);
-void bopti_end(const unsigned char *end, int x, int y, int width);
+void bopti_end_nover(const unsigned char *end, int size, struct Command *c);
+void bopti_end(const unsigned char *end, int size, struct Command *c);
 
 /*
 	bopti()
 	Draws a layer in the video ram.
 */
-void bopti(const unsigned char *layer, int x, int y, int columns,
-	int end_size);
+void bopti(const unsigned char *layer, struct Structure *s, struct Command *c);
 
 /*
 	getStructure()
 	Determines the image size and data pointer.
 */
-void getStructure(struct Image *img, int *width, int *height, int *layer_size,
-	const unsigned char **data, int *columns, int *end_size);
+void getStructure(struct Image *img, struct Structure *structure);
 
 #endif	// _BOPTI_INTERNALS_H
diff --git a/src/bopti/dimage.c b/src/bopti/dimage.c
index f0df4b5..3da393f 100644
--- a/src/bopti/dimage.c
+++ b/src/bopti/dimage.c
@@ -7,17 +7,33 @@
 */
 void dimage(struct Image *img, int x, int y)
 {
-	int width, layer_size, columns, end;
-	int format = img->format, i = 0;
-	const unsigned char *data;
-
 	if(img->magic != 0xb7) return;
-	if(img->format != Format_Mono && img->format != Format_MonoAlpha)
-		return;
-	op = bopti_op_mono;
 
-	// 'height' refers to a static variable for this file.
-	getStructure(img, &width, &height, &layer_size, &data, &columns, &end);
+	struct Structure s;
+	struct Command command;
+	int actual_width;
+	int format = img->format, i = 0;
+
+	if(format != Format_Mono && format != Format_MonoAlpha) return;
+	getStructure(img, &s);
+
+	//---
+	//	Adjusting image parameters.
+	//---
+
+	if(x + s.width < 0 || x > 127 || y + s.height < 0 || y > 63) return;
+
+	command.top	= (y < 0) ? (-y) : (0);
+	command.bottom	= (y + s.height > 64) ? (64 - y) : (s.height);
+	command.left	= ((x < 0) ? (-x) : (0)) >> 5;
+	actual_width	= (x + s.width > 128) ? (128 - x) : (s.width);
+	command.right	= ((actual_width + 31) >> 5) - 1;
+
+	command.x	= x;
+	command.y	= y;
+	command.op	= bopti_op_mono;
+
+	getMasks(x, x + actual_width - 1, command.masks);
 
 	vram = display_getCurrentVRAM();
 
@@ -26,9 +42,9 @@ void dimage(struct Image *img, int x, int y)
 		// Drawing every layer, in order of formats.
 		if(format & 1)
 		{
-			channel = (1 << i);
-			bopti(data, x, y, columns, end);
-			data += layer_size;
+			command.channel = (1 << i);
+			bopti(s.data, &s, &command);
+			s.data += s.layer_size;
 		}
 
 		format >>= 1;
diff --git a/src/bopti/gimage.c b/src/bopti/gimage.c
index d9904af..dd31143 100644
--- a/src/bopti/gimage.c
+++ b/src/bopti/gimage.c
@@ -1,4 +1,5 @@
 #include <bopti_internals.h>
+#include <display.h>
 #include <gray.h>
 
 /*
@@ -7,15 +8,31 @@
 */
 void gimage(struct Image *img, int x, int y)
 {
-	int width, layer_size, columns, end;
-	int format = img->format, i = 0;
-	const unsigned char *data;
-
 	if(img->magic != 0xb7) return;
-	op = bopti_op_gray;
 
-	// 'height' refers to a static variable for this file.
-	getStructure(img, &width, &height, &layer_size, &data, &columns, &end);
+	struct Structure s;
+	struct Command command;
+	int actual_width;
+	int format = img->format, i = 0;
+
+	getStructure(img, &s);
+
+	//---
+	//	Adjusting image parameters.
+	//---
+//-65:-68
+	if(x + s.width < 0 || x > 127 || y + s.height < 0 || y > 63) return;
+
+	command.top	= (y < 0) ? (-y) : (0);
+	command.bottom	= (y + s.height > 64) ? (64 - y) : (s.height);
+	command.left	= ((x < 0) ? (-x) : (0)) >> 5;
+	actual_width	= (x + s.width > 128) ? (128 - x) : (s.width);
+	command.right	= ((actual_width + 31) >> 5) - 1;
+
+	command.op	= bopti_op_gray;
+
+	if(x >= 0) getMasks(x, x + actual_width - 1, command.masks);
+	else getMasks(0, actual_width + x - 1, command.masks);
 
 	v1 = gray_lightVRAM();
 	v2 = gray_darkVRAM();
@@ -25,9 +42,13 @@ void gimage(struct Image *img, int x, int y)
 		// Drawing every layer, in order of formats.
 		if(format & 1)
 		{
-			channel = (1 << i);
-			bopti(data, x, y, columns, end);
-			data += layer_size;
+			// These members are modified by bopti()!
+			command.x = x;
+			command.y = y;
+			command.channel = (1 << i);
+
+			bopti(s.data, &s, &command);
+			s.data += s.layer_size;
 		}
 
 		format >>= 1;
diff --git a/src/core/crt0.c b/src/core/crt0.c
index a323234..3bb31da 100644
--- a/src/core/crt0.c
+++ b/src/core/crt0.c
@@ -53,8 +53,8 @@ int start(void)
 	__GLibAddinAplExecutionCheck(0, 1, 1);
 
 	// Initializing everything.
-	init();
 	gint_init();
+	init();
 
 
 
@@ -69,8 +69,8 @@ int start(void)
 	// Remember to flush and close opened streams.
 
 	// Un-initializing everything.
-	gint_quit();
 	fini();
+	gint_quit();
 
 	return exit_code;
 }
diff --git a/src/core/gint.c b/src/core/gint.c
index b7c9c45..d6098e0 100644
--- a/src/core/gint.c
+++ b/src/core/gint.c
@@ -91,6 +91,11 @@ void gint_init(void)
 	unsigned int *ptr = &bgint;
 	unsigned int *src = &gint_data;
 
+	// This initialization routine is usually called before any
+	// constructor. We want to ensure that the MPU type is detected, but
+	// mpu_init() hasn't been called yet.
+	mpu_init();
+
 	// Loading the interrupt handler into the memory.
 	while(ptr < &egint) *ptr++ = *src++;
 
diff --git a/src/core/gint_callback.c b/src/core/gint_callback.c
index e90e4c2..d9d1ee7 100644
--- a/src/core/gint_callback.c
+++ b/src/core/gint_callback.c
@@ -1,6 +1,8 @@
 #include <gint.h>
 #include <mpu.h>
 
+#include <stddef.h>
+
 static void (*rtc_callback)(void) = NULL;
 
 /*
diff --git a/src/display/dclear_area.c b/src/display/dclear_area.c
index 0b9aadb..2648178 100644
--- a/src/display/dclear_area.c
+++ b/src/display/dclear_area.c
@@ -8,7 +8,7 @@
 */
 void dclear_area(int x1, int y1, int x2, int y2)
 {
-	unsigned int masks[4];
+	uint32_t masks[4];
 	adjustRectangle(&x1, &y1, &x2, &y2);
 	getMasks(x1, x2, masks);
 
diff --git a/src/display/display_internals.h b/src/display/display_internals.h
index 7c3471a..560a0c8 100644
--- a/src/display/display_internals.h
+++ b/src/display/display_internals.h
@@ -4,25 +4,6 @@
 //
 //	Handles vram manipulation and drawing.
 //
-//
-//	:: Rectangle masks
-//
-//	The concept of 'rectangle masks' is used several times in this module.
-//	It is based on the fact that an operation that affects a rectangle acts
-//	the same on all its lines. Therefore the behavior of the operation is
-//	determined by its behavior on a single line, which is represented using
-//	'masks' whose bits indicate whether a pixel is affected (1) or not (0).
-//
-//	For example when clearing the screen rectangle (16, 16, 112, 48), the
-//	masks will represent information '16 to 112 on x-axis', and will hold
-//	the following values : 0000ffff, ffffffff, ffffffff and ffff0000. These
-//	masks can then be used by setting vram[offset] &= ~masks[i]. This
-//	appears to be very flexible : for instance, vram[offset] ^= masks[i]
-//	will reverse the pixels in the same rectangle.
-//
-//	This technique can also be used in more subtle cases with more complex
-//	patterns, but within this module it is unlikely to happen.
-//
 //---
 
 #ifndef	_DISPLAY_INTERNALS_H
@@ -30,23 +11,4 @@
 
 extern int *vram;
 
-/*
-	adjustRectangle()
-	Adjusts the given rectangle coordinates to ensure that :
-	- the rectangle is entirely contained in the screen
-	- x1 < x2
-	- y1 < y2
-	which is needed when working with screen rectangles.
-*/
-static void adjustRectangle(int *x1, int *y1, int *x2, int *y2);
-
-/*
-	getMasks()
-	Computes the rectangle masks needed to affect pixels located between x1
-	and x2 (both included). The four masks are stored in the third argument
-	(seen as an array).
-	See this module's internals header file for more information.
-*/
-static void getMasks(int x1, int x2, unsigned int *masks);
-
 #endif	// _DISPLAY_INTERNALS_H
diff --git a/src/display/dline.c b/src/display/dline.c
index 3f90483..69e331d 100644
--- a/src/display/dline.c
+++ b/src/display/dline.c
@@ -13,7 +13,7 @@
 
 static void dhline(int x1, int x2, int y, enum Color color)
 {
-	unsigned int masks[4];
+	uint32_t masks[4];
 	int offset = y << 2;
 	int i;
 
diff --git a/src/display/dreverse_area.c b/src/display/dreverse_area.c
index f3c48fe..c9eeaee 100644
--- a/src/display/dreverse_area.c
+++ b/src/display/dreverse_area.c
@@ -9,7 +9,7 @@
 */
 void dreverse_area(int x1, int y1, int x2, int y2)
 {
-	unsigned int masks[4];
+	uint32_t masks[4];
 	adjustRectangle(&x1, &y1, &x2, &y2);
 	getMasks(x1, x2, masks);
 
diff --git a/src/display/getMasks.c b/src/display/getMasks.c
index bb2b32f..6f3091c 100644
--- a/src/display/getMasks.c
+++ b/src/display/getMasks.c
@@ -1,13 +1,12 @@
-#include <display_internals.h>
+#include <display.h>
 
 /*
 	getMasks()
 	Computes the rectangle masks needed to affect pixels located between x1
 	and x2 (both included). The four masks are stored in the third argument
 	(seen as an array).
-	See this module's internals header file for more information.
 */
-void getMasks(int x1, int x2, unsigned int *masks)
+void getMasks(int x1, int x2, uint32_t *masks)
 {
 	// Indexes of the first and last longs that are non-blank.
 	int l1 = x1 >> 5;
diff --git a/src/gray/gray_engine.c b/src/gray/gray_engine.c
index 12015df..de4f0e4 100644
--- a/src/gray/gray_engine.c
+++ b/src/gray/gray_engine.c
@@ -11,7 +11,7 @@
 #include <timer.h>
 
 static int internal_vrams[3][256];
-const void *vrams[4];
+static const void *vrams[4];
 
 static int current = 0;
 static int delays[2];
@@ -33,7 +33,10 @@ static int runs = 0;
 */
 void gray_start(void)
 {
+	if(runs) return;
+
 	timer_start(TIMER_GRAY, delays[0], GRAY_PRESCALER, gray_interrupt, 0);
+	current &= 1;
 	runs = 1;
 }
 
@@ -44,6 +47,8 @@ void gray_start(void)
 */
 void gray_stop(void)
 {
+	if(!runs) return;
+
 	timer_stop(TIMER_GRAY);
 	runs = 0;
 
@@ -79,18 +84,18 @@ inline int gray_runs(void)
 	gray_lightVRAM()
 	Returns the module's gray vram address.
 */
-inline void *gray_lightVRAM(void)
+void *gray_lightVRAM(void)
 {
-	return (void *)vrams[current & 2];
+	return (void *)vrams[~current & 2];
 }
 
 /*
 	gray_lightVRAM()
 	Returns the module's dark vram address.
 */
-inline void *gray_darkVRAM(void)
+void *gray_darkVRAM(void)
 {
-	return (void *)vrams[(current & 2) | 1];
+	return (void *)vrams[(~current & 2) | 1];
 }
 
 /*
@@ -130,7 +135,7 @@ inline void gupdate(void)
 */
 void gray_interrupt(void)
 {
-	timer_reload(TIMER_GRAY, delays[current & 1]);
+	timer_reload(TIMER_GRAY, delays[(~current) & 1]);
 	screen_display(vrams[current]);
 	current ^= 1;
 }
@@ -146,6 +151,6 @@ void gray_init(void)
 	vrams[2] = (const void *)internal_vrams[1];
 	vrams[3] = (const void *)internal_vrams[2];
 
-	delays[0] = 900;
-	delays[1] = 1000;
+	delays[0] = 993;
+	delays[1] = 1609;
 }
diff --git a/src/keyboard/keyboard_internals.h b/src/keyboard/keyboard_internals.h
index b4a5b2c..b08678b 100644
--- a/src/keyboard/keyboard_internals.h
+++ b/src/keyboard/keyboard_internals.h
@@ -5,7 +5,7 @@
 
 // Keyboard variables.
 extern volatile unsigned char keyboard_state[10];
-extern volatile int interrupt_flag = 0;
+extern volatile int interrupt_flag;
 
 // Key statistics.
 extern int repeat_first, repeat_next;
diff --git a/src/keyboard/keyboard_interrupt.c b/src/keyboard/keyboard_interrupt.c
index 4bf12ae..e76aca1 100644
--- a/src/keyboard/keyboard_interrupt.c
+++ b/src/keyboard/keyboard_interrupt.c
@@ -42,8 +42,7 @@ void keyboard_interrupt(void)
 */
 void keyboard_init(void)
 {
-	timer_start(TIMER_KEYBOARD, 1700, TIMER_Po_256, keyboard_interrupt,
-		0);
+	timer_start(TIMER_KEYBOARD, 1700, TIMER_Po_256, keyboard_interrupt, 0);
 }
 
 /*
diff --git a/src/tales/gtext.c b/src/tales/gtext.c
new file mode 100644
index 0000000..b12d483
--- /dev/null
+++ b/src/tales/gtext.c
@@ -0,0 +1,14 @@
+#include <tales.h>
+#include <gray.h>
+
+/*
+	gtext()
+	Prints the given raw string.
+*/
+void gtext(const char *str, int x, int y)
+{
+	display_useVRAM(gray_lightVRAM());
+	dtext(str, x, y);
+	display_useVRAM(gray_darkVRAM());
+	dtext(str, x, y);
+}
diff --git a/src/tales/tales_configuration.c b/src/tales/tales_configuration.c
index be38c33..eb2aefa 100644
--- a/src/tales/tales_configuration.c
+++ b/src/tales/tales_configuration.c
@@ -5,7 +5,7 @@
 	text_configure()
 	Sets the font and mode to use for the following print operations.
 */
-void text_configure(struct Font *font)
+void text_configure(struct Font *next_font)
 {
 	font = next_font;
 }
diff --git a/src/timer/timer_interrupt.c b/src/timer/timer_interrupt.c
index 182ea9c..5af1d6c 100644
--- a/src/timer/timer_interrupt.c
+++ b/src/timer/timer_interrupt.c
@@ -1,6 +1,8 @@
 #include <timer.h>
 #include <timer_internals.h>
 
+#include <stddef.h>
+
 struct Timer timers[3] = { { NULL, 0 }, { NULL, 0 }, { NULL, 0 } };
 
 /*
@@ -9,7 +11,6 @@ struct Timer timers[3] = { { NULL, 0 }, { NULL, 0 }, { NULL, 0 } };
 */
 void timer_interrupt(int timer)
 {
-	// Getting the timer address.
 	struct mod_tmu *tmu;
 	timer_get(timer, &tmu, NULL);
 
diff --git a/src/timer/timer_stop.c b/src/timer/timer_stop.c
index ab58f1e..1c77d5a 100644
--- a/src/timer/timer_stop.c
+++ b/src/timer/timer_stop.c
@@ -1,6 +1,8 @@
 #include <timer.h>
 #include <timer_internals.h>
 
+#include <stddef.h>
+
 /*
 	timer_stop()
 	Stops the given timer. This function may be called even if the timer is