diff --git a/board/fxcg50/board.ini b/board/fxcg50/board.ini
index b04f743..005b434 100644
--- a/board/fxcg50/board.ini
+++ b/board/fxcg50/board.ini
@@ -7,5 +7,5 @@ mpu=sh7305
 
 [toolchain]
 prefix=sh-elf-vhex-
-cflags=-DFXCG50,-m4-nofpu,-mb
+cflags=-DFXCG50,-m4-nofpu,-mb,-DWIDTH=396,-DHEIGHT=224
 libs=-lgcc
diff --git a/board/fxcg50/fxcg50-dynamic.ld b/board/fxcg50/fxcg50-dynamic.ld
new file mode 100644
index 0000000..d714a9c
--- /dev/null
+++ b/board/fxcg50/fxcg50-dynamic.ld
@@ -0,0 +1,98 @@
+/*
+	Linker script for the dynamic version of Vhex (fxcg50)
+*/
+
+OUTPUT_FORMAT("elf32-sh", "elf32-sh", "elf32-sh")
+OUTPUT_ARCH(sh4)
+ENTRY(_main)
+
+
+/*
+** Linker script for user executables.
+*/
+MEMORY
+{
+	/* virtual memory, read-write segment */
+	userram (WX) : o = 0x00000000, l = 1M
+}
+
+SECTIONS
+{	/* Code */
+	.text : {
+		*(.text);
+		*(.text.*);
+
+		_bctors = . ;
+		*(.ctors .ctors.*)
+		_ectors = . ;
+
+		_bdtors = . ;
+		*(.dtors .dtors.*)
+		_edtors = . ;
+
+	} > userram
+
+	/* Read-only sections */
+	.rodata : {
+		/* Read-Only data */
+		*(.rodata);
+		*(.rodata.*);
+	} > userram
+
+
+	/* The GOT section is a bit exotic.
+	   When I generate the PIE executable, all global variables are stored
+	   is the *(.got) section and the __GLOBAL_OFFSET_TABLE__ object is
+	   generated and inserted in the *(.got.plt) section.
+
+	   But, neither of *(.plt*) or *(rela*) section are generated to help
+	   me out for the "relocation" of each address stored in the GOT. The
+	   result is that the content of the GOT is always absolute addresses,
+	   which makes the machine crash.
+
+	   So, the idea to bypass this limitation (probably due to the custom
+	   GCC which not provide critical information for the relocation) is to
+	   isolate the GOT in a standalone section and, after the loading of
+	   the image, walk thought the relocalised table and manually patch
+	   each address.
+
+	   Moreover, the __GLOBAL_OFFSET_TABLE__ is used like a table, so, the
+	   section ".got.plt" SHOULD be before the .got section. */
+	.got.plt : { *(.got.plt) *(.igot.plt) *(.igot) }
+	.got     : { *(.got) }
+
+	/* readable / writable data */
+	.data ALIGN(4) : {
+		*(.data);
+		*(.data.*);
+		*(COMMON);
+	}
+
+	/* bss section included to avoid missaligned segment */
+	.bss ALIGN(4) : {
+		*(.bss);
+		*(.bss.*);
+
+		/* dynamic BSS information (move me ?) */
+		*(.dynbss)
+	} > userram
+
+	/* unwanted section */
+	/DISCARD/ : {
+		*(.rela.debug*)
+		*(.gnu.*)
+		*(.debug_info)
+		*(.debug_abbrev)
+		*(.debug_loc)
+		*(.debug_aranges)
+		*(.debug_ranges)
+		*(.debug_line)
+		*(.debug_str)
+		*(.debug_*)
+		*(.jcr)
+		*(.eh_frame_hdr)
+		*(.eh_frame)
+		*(.comment)
+		*(.interp)
+	}
+}
diff --git a/board/fxcg50/hardware.c b/board/fxcg50/hardware.c
index 1ef8ea6..95e343a 100644
--- a/board/fxcg50/hardware.c
+++ b/board/fxcg50/hardware.c
@@ -1,8 +1,8 @@
 //---
 //	vhex:core:hardware - Platform information and hardware detection
 //---
-#include "vhex/drivers/mpu/sh/sh7305/pfc.h"
-#include "vhex/drivers/mmu.h"
+#include "vhex/driver/mpu/sh/sh7305/pfc.h"
+#include "vhex/driver/mmu.h"
 #include "board/fxcg50/hardware.h"
 #include "vhex/hardware.h"
 
diff --git a/board/fxcg50/hypervisor.c b/board/fxcg50/hypervisor.c
index eb71f86..d33eb4d 100644
--- a/board/fxcg50/hypervisor.c
+++ b/board/fxcg50/hypervisor.c
@@ -3,15 +3,11 @@
 /* hypervisor_init() : initialize the hypervisor module */
 void hypervisor_init(void)
 {
-	hyp_world_t casio = hypervisor_world_new(
-		"casio",
-		HYP_WORLD_STATUS_FLAG_UNDELETABLE
-	);
-	hyp_world_t vhex = hypervisor_world_new(
-		"vhex",
-		HYP_WORLD_STATUS_FLAG_UNDELETABLE
-	);
+	hyp_world_t casio = hypervisor_world_new("casio");
+	hyp_world_t vhex = hypervisor_world_new("vhex");
+
 	hypervisor_world_switch(casio, vhex);
+
 }
 
 /* hypervisor_quit() : quit the hypervisor module */
diff --git a/config b/config
deleted file mode 100755
index d3713ff..0000000
--- a/config
+++ /dev/null
@@ -1,225 +0,0 @@
-#! /bin/python3
-import sys
-import configparser
-import os.path
-import os
-import shutil
-
-
-help_string = f"""
-usage: config [options...]
-
-Configuration script for the Vhex unikernel. You should build out-of-tree by
-creating a build directory and configuring from there.
-
-Options:
-    -h,--help
-        display this message
-
-    --verbose
-        display more information during the compilation step
-
-    --format=FORMAT[,format[,...]]
-        select the format of the library generation. You can use two format:
-            <> static  - generate a static library
-            <> dynamic - generate a dynamic library
-            <> all     - same behaviour as "--format=static,dynamic"
-        By default, only "dynamic" is used.
-
-    --board[=BOARD,board[,...]]
-        select boards. If no board name is given, a list of all available board
-        will be printed.
-
-    --prefix=PATH
-        installation path for all generated libraries
-""".strip()
-
-#
-# create and apply the arguments parser
-#
-
-def parse_arguments():
-    """
-    The objectif of this function is to generate the "arguments object" with
-    all arguments passed throuth this script correctly isolated.
-    """
-    args = {
-        'board' : [],
-        'format' : [],
-        'verbose': False,
-        'prefix': ''
-    }
-    arg_name = [
-            "-h",
-            "--help",
-            "--format",
-            "--verbose",
-            "--board",
-            "--prefix"
-    ]
-    for arg in sys.argv[1:]:
-        info = arg.split("=")
-        if (info[0] in arg_name) == False:
-            print("%s: unreconized option '%s'" % (sys.argv[0],info[0]))
-            print("Try '%s --help' for more information" % sys.argv[0])
-            exit(84)
-        if (info[0] in ["-h", "--help"]) == True:
-            print(help_string)
-            exit(0)
-        if info[0] == "--verbose":
-            args["verbose"] = True
-            continue
-        if info[0] == "--prefix":
-            args["prefix"] = info[1]
-            continue
-        if len(info) > 1:
-            args[info[0][2:]] = info[1].split(",")
-    return args
-
-
-#
-# part handlers
-#
-
-def board_check(file, board_list):
-    boards = list(os.walk('../board'))[0][1]
-    archs  = list(os.walk('../src/drivers/mpu'))[0][1]
-
-    if not board_list:
-        print('board available:')
-        for board in boards:
-            path = '../board/%s/board.ini' % board
-            if not os.path.exists(path):
-                print('board \'%s\' does not exists' % board)
-                continue
-            conf = configparser.ConfigParser()
-            conf.read(path)
-            if not ('meta' in conf) or not ('description' in conf['meta']):
-                print('<> %s\t\tNo description available' % board)
-                continue
-            print('<> %s\t\t%s' % (board, conf['meta']['description']))
-        exit(0)
-
-
-    valid_board_list = []
-    for board in board_list:
-        if not (board in boards):
-            print("board '%s' does not exist" % board)
-            continue
-        path = '../board/%s/board.ini' % board
-        if not os.path.exists(path):
-            print("board '%s' does not have INI descriptor file" % board)
-            continue
-        conf = configparser.ConfigParser()
-        conf.read(path)
-        if not ('drivers' in conf) or not ('mpu' in conf['drivers']):
-            print("board '%s' does not have MPU information" % board)
-            continue
-        arch = ''
-        mpu = conf['drivers']['mpu']
-        for _arch in archs:
-            if not os.path.exists('../src/drivers/mpu/%s/%s' % (_arch,mpu)):
-                continue
-            arch = _arch
-            break
-        if not arch:
-            print("board '%s': unreconized MPU '%s'" % (board,mpu))
-            continue
-
-        pathlist = [
-            '../board/%s' % board,
-            '../src/drivers/mpu/%s/%s' % (_arch,mpu)
-        ]
-        for driver in conf['drivers']:
-            if driver == 'mpu':
-                continue
-            dpath = '../src/drivers/%s' % driver
-            if not os.path.exists(dpath):
-                print("board '%s': unreconized driver \'%s\'" % (board, dpath))
-                continue
-            for t in conf['drivers'][driver].split(','):
-                tpath = dpath + '/' + t
-                if not os.path.exists(tpath):
-                    print("board '%s': unreconized driver \'%s\'" % (board, t))
-                    continue
-                pathlist.append(tpath)
-                tpath = tpath + '/target/' + arch
-                if os.path.exists(tpath):
-                    pathlist.append(tpath)
-        for dirent in os.listdir('../src'):
-            if not (dirent in ['drivers', 'arch']):
-                pathlist.append('../src/' + dirent)
-
-        ldflags,cflags,prefix,libs = [],[],[],[]
-        if 'toolchain' in conf:
-            if 'prefix' in conf['toolchain']:
-                prefix = conf['toolchain']['prefix']
-            if 'cflags' in conf['toolchain']:
-                cflags = conf['toolchain']['cflags'].split(',')
-            if 'libs' in conf['toolchain']:
-                libs = conf['toolchain']['libs'].split(',')
-
-        confstr = 'CONFIG.' + board;
-        file.write(
-                confstr + '.SRC-MODULE-PATH  :=' + ' '.join(pathlist) + '\n'
-              + confstr + '.TOOLCHAIN.LDFLAGS :=' + ' '.join(ldflags) + '\n'
-              + confstr + '.TOOLCHAIN.CFLAGS  :=' + ' '.join(cflags) + '\n'
-              + confstr + '.TOOLCHAIN.PREFIX  :=' + prefix + '\n'
-              + confstr + '.LIBS :=' + ' '.join(libs) + '\n'
-        )
-
-        if not os.path.exists(board):
-            os.mkdir(board)
-            os.symlink(
-                '../../board/%s/%s.ld' % (board,board),
-                '%s/%s.ld' % (board,board)
-            )
-
-        valid_board_list.append(board)
-
-    file.write('CONFIG.BOARD-LIST := ' + ' '.join(valid_board_list) + '\n')
-
-def format_check(file, format_list):
-    file.write('CONFIG.FORMAT-LIST :=')
-    for _format in format_list:
-        if not (_format in ["static", "dynamic", "all"]):
-            print("%s: unreconized format '%s'" % (sys.argv[0], _format))
-            exit(84)
-        if _format == 'all':
-            file.write(' dynamic static\n')
-            return
-        file.write(' ' + _format)
-    if not format_list:
-        file.write(' dynamic')
-    file.write('\n')
-
-def prefix_check(file, prefix):
-    file.write('CONFIG.INSTALL-PREFIX :=' + prefix + '\n')
-
-def verbose_check(file, verbose):
-    file.write(f"CONFIG.VERBOSE := {'true' if verbose else 'false'}\n")
-
-#
-# "real" entry of the script
-#
-
-def main():
-    args = parse_arguments()
-
-    if os.path.exists('../src') == False:
-        print('error: you should configure from a build directory, like this:')
-        print('  mkdir build && cd build && ../configure [options..]')
-        exit(84)
-
-    file = open('kernel.cfg', 'w')
-
-    board_check(file, args['board'])
-    format_check(file, args['format'])
-    prefix_check(file, args['prefix'])
-    verbose_check(file, args['verbose'])
-
-    if os.path.exists('Makefile'):
-        os.remove('Makefile')
-    os.symlink('../make/Makefile', 'Makefile')
-
-main()
diff --git a/include/vhex/display.h b/include/vhex/display.h
index 59aefbd..9f03900 100644
--- a/include/vhex/display.h
+++ b/include/vhex/display.h
@@ -1,24 +1,38 @@
 #ifndef __VHEX_DISPLAY__
 # define __VHEX_DISPLAY__
 
-//TODO: plate-form specific
-enum {
-	/* Compatibility with fx9860g color names */
-	C_WHITE = 0xffff,
-	C_LIGHT = 0xad55,
-	C_DARK  = 0x528a,
-	C_BLACK = 0x0000,
+#include <vhex/defs/types.h>
+#include <vhex/display/types.h>
+#include <vhex/display/draw.h>
+#include <vhex/display/color.h>
+//#include <vhex/display/image.h>
+//#include <vhex/display/text.h>
 
-	/* Other colors */
-	C_RED   = 0xf800,
-	C_GREEN = 0x07e0,
-	C_BLUE  = 0x001f,
+//TODO: doc
 
-	C_NONE = -1,
-	C_INVERT = -2,
-};
+/* dclear(): Fill the screen with a single color */
+extern did_t dclear(int color);
+
+/* dupdate(): Generate the display frame on the screen */
+extern void dupdate(void);
+
+/* dwidth(): get the screen width */
+extern size_t dwidth(void);
+
+/* dheight(): get the heigth of the screen */
+extern size_t dheight(void);
 
 
+
+
+
+
+
+
+//---
+// Text render API
+//---
+#if 0
 /* Alignment settings for dtext_opt() and dprint_opt(). Combining a vertical
    and a horizontal alignment option specifies where a given point (x,y) should
    be relative to the rendered string. */
@@ -42,14 +56,13 @@ extern void dtext_opt(
 	char const *str, int size
 );
 
+
+
+
 /* dpixel(): Change a pixel's color */
 extern void dpixel(int x, int y, int color);
 
-/* dupdate(): Push the video RAM to the display driver */
-extern void dupdate(void);
 
-/* dclear(): Fill the screen with a single color */
-extern void dclear(int color);
 
 /* dascii() : display one ASCII character */
 extern void dascii(int x, int y, int fg, int bg, int n);
@@ -78,4 +91,6 @@ extern void dhline(int x1, int x2, int y, int color);
 /* dvline(): Draw vertical line */
 extern void dvline(int y1, int y2, int x, int color);
 
+#endif /* IF 0 */
+
 #endif /*__VHEX_DISPLAY__*/
diff --git a/include/vhex/display/color.h b/include/vhex/display/color.h
new file mode 100644
index 0000000..9fcc2fc
--- /dev/null
+++ b/include/vhex/display/color.h
@@ -0,0 +1,20 @@
+#ifndef __VHEX_DISPLAY_COLOR__
+# define __VHEX_DISPLAY_COLOR__
+
+
+//FIXME: this is plateform-specific :/
+enum {
+	C_WHITE = 0xffff,
+	C_LIGHT = 0xad55,
+	C_DARK  = 0x528a,
+	C_BLACK = 0x0000,
+
+	C_RED   = 0xf800,
+	C_GREEN = 0x07e0,
+	C_BLUE  = 0x001f,
+
+	C_NONE = -1,
+	C_INVERT = -2,
+};
+
+#endif /* __VHEX_DISPLAY_COLOR__ */
diff --git a/include/vhex/display/draw.h b/include/vhex/display/draw.h
new file mode 100644
index 0000000..df1520d
--- /dev/null
+++ b/include/vhex/display/draw.h
@@ -0,0 +1 @@
+#include <vhex/display/draw/circle.h>
diff --git a/include/vhex/display/draw/circle.h b/include/vhex/display/draw/circle.h
new file mode 100644
index 0000000..2b8e62b
--- /dev/null
+++ b/include/vhex/display/draw/circle.h
@@ -0,0 +1,29 @@
+#ifndef __VHEX_DISPLAY_DRAW_CIRCLE__
+# define __VHEX_DISPLAY_DRAW_CIRCLE__
+
+#include <vhex/display/shader.h>
+#include <vhex/display/types.h>
+
+/* dcircle_filled() : draw a filled circle
+
+   This function will add a filled circle drawing in the internal "draw queue"
+   handled by vhex display core. The "draw ID" will be returned and shader can
+   be added to the circle afterward.
+
+  Args:
+  ( in) x     : X position (horizontal middle of the circle)
+  ( in) y     : Y position (vertical   middle of the circle)
+  ( in) size  : diameter of the circle
+  ( in) color : filled color for the circle
+
+  Return:
+  > the "draw ID", which can be used to apply shader afterward */
+extern did_t dcircle(int x, int y, size_t size, int mode, dshader_t *list);
+
+//TODO: shader
+//TODO: doc
+//TODO: mode
+
+
+
+#endif /* __VHEX_DISPLAY_DRAW_CIRCLE__ */
diff --git a/include/vhex/display/shader.h b/include/vhex/display/shader.h
new file mode 100644
index 0000000..72a1229
--- /dev/null
+++ b/include/vhex/display/shader.h
@@ -0,0 +1,90 @@
+#ifndef __VHEX_DISPLAY_SHADER__
+# define __VHEX_DISPLAY_SHADER__
+
+#include <vhex/defs/attributes.h>
+#include <vhex/defs/types.h>
+
+/* dshader_call_arg_t: All types of arguments allowed in an indirect shader call
+
+   Because a function call cannot be easily pieced together, there are
+   restrictions on what arguments can be passed. The following union lists all
+   of the available types. Other types can be used if casted, mainly pointers;
+   see the description of DSHADER*() for details. */
+typedef union dshader_call_arg {
+	int8_t i8;
+	uint8_t u8;
+
+	int16_t i16;
+	uint16_t u16;
+
+	/* 32-bit integers */
+	int i;
+	unsigned int u;
+	int32_t i32;
+	uint32_t u32;
+	/* 32-bit floating-point */
+	float f;
+
+	/* Pointers to most common types, in all possible const/volatile
+	   qualifications */
+	#define POINTER(type, name) \
+	type *name; \
+	type const *name ## _c; \
+	type volatile *name ## _v; \
+	type volatile const *name ## _cv;
+
+	POINTER(void, pv)
+	POINTER(char, pc)
+	POINTER(unsigned char, puc)
+	POINTER(short, ps)
+	POINTER(unsigned short, pus)
+	POINTER(int, pi)
+	POINTER(unsigned int, pui)
+	POINTER(int8_t, pi8)
+	POINTER(uint8_t, pu8)
+	POINTER(int16_t, pi16)
+	POINTER(uint16_t, pu16)
+	POINTER(int32_t, pi32)
+	POINTER(uint32_t, pu32)
+	POINTER(int64_t, pi64)
+	POINTER(uint64_t, pu64)
+	POINTER(long long int, pll)
+	POINTER(unsigned long long int, pull)
+	POINTER(float, pf)
+	POINTER(double, pd)
+
+	#undef POINTER
+} dshader_call_arg_t;
+
+/* dshader_surface - Describe the surface */
+struct dshader_surface {
+	void *draw;
+	void *frag;
+	size_t width;
+	size_t height;
+	unsigned int x;
+	unsigned int y;
+};
+
+/* dshader - display shader definition */
+struct dshader_call {
+	int (*routine)(
+		struct dshader_surface *surface,
+		dshader_call_arg_t *draw_args,
+		dshader_call_arg_t *shader_args
+	);
+	dshader_call_arg_t args[8];
+};
+typedef struct dshader_call dshader_call_t;
+typedef struct dshader_call dshader_t;
+
+/* DSHADER_LIST - helper to create a list of shader "on-the-fly" */
+#define DSHADER_LIST(shader_list) (dshader_call_t*)&{ shader_list }
+
+/* DSHADER - helper to create a shader object */
+#define DSHADER(fct, ...) (dshader_call_t){	\
+	.routine = fct,				\
+	.args = { __VA_ARGS__ }			\
+}
+
+#endif /* __VHEX_DISPLAY_SHADER__ */
diff --git a/include/vhex/display/stack.h b/include/vhex/display/stack.h
new file mode 100644
index 0000000..1cebb1d
--- /dev/null
+++ b/include/vhex/display/stack.h
@@ -0,0 +1,87 @@
+#ifndef __VHEX_DISPLAY_STACK__
+# define __VHEX_DISPLAY_STACK__
+
+#include <vhex/display/shader.h>
+#include <vhex/display/types.h>
+
+/* dstack_call - dstack indirect call (same as dshader) */
+struct dstack_call {
+	int (*routine)(
+		struct dshader_surface *surface,
+		dshader_call_arg_t *draw_args
+	);
+	dshader_call_arg_t args[12];
+};
+typedef struct dstack_call dstack_call_t;
+
+/* dstack_action - dstack drawing action information */
+struct dstack_action {
+	struct dstack_call call;
+	struct {
+		dshader_call_t *table;
+		int number;
+		int idx;
+	} shader;
+};
+
+/* DSTACK_CALL - display indirect call */
+#pragma GCC diagnostic ignored "-Wmissing-braces"
+
+#define DSTACK_CALL(fct, ...) (dstack_call_t){	\
+	.routine = (void*)fct,			\
+	.args = { __VA_ARGS__ }			\
+}
+
+
+/* dstack_config - dstack configuration structure */
+struct dstack_config {
+	int default_icall_pool_slot;
+	int default_icall_args_nb;
+	int default_shader_per_action;
+};
+
+#ifndef DSTACK_DEFAULT_ICALL_SLOT
+# define DSTACK_DEFAULT_ICALL_SLOT		32
+#endif
+
+#ifndef DSTACK_DEFAULT_ICALL_ARGS
+# define DSTACK_DEFAULT_ICALL_ARGS		12
+#endif
+
+#ifndef DSTACK_DEFAULT_SHADER_PER_ACTION
+# define DSTACK_DEFAULT_SHADER_PER_ACTION	4
+#endif
+
+/* dstack_drv_interface - driver interface */
+struct dstack_drv_interface {
+	int (*frame_start)(struct dshader_surface *);
+	int (*frame_frag_next)(struct dshader_surface *);
+	int (*frame_frag_send)(struct dshader_surface *);
+	int (*frame_end)(struct dshader_surface *);
+};
+
+//---
+// Display stack API
+//---
+
+/* dstack_init() : Initialise the draw stack (should not be involved) */
+extern int dstack_init(struct dstack_config *config);
+
+/* dstack_add_action() : add a new action in the draw stack */
+extern did_t dstack_add_action(dstack_call_t *call, dshader_call_t *shaders);
+
+/* dstack_get_action() : get display stack action using its ID */
+extern struct dstack_action *dstack_get_action(did_t did);
+
+/* dstack_render(): render a frame */
+extern void dstack_render(void);
+
+/* dstack_invalidate() : Invalidate the draw stack (reset) */
+extern int dstack_invalidate(void);
+
+/* dstack_quit() : Uninit the draw stack */
+extern int dstack_quit(void);
+
+
+
+#endif /* __VHEX_DISPLAY_STACK__ */
diff --git a/include/vhex/display/types.h b/include/vhex/display/types.h
new file mode 100644
index 0000000..ef15607
--- /dev/null
+++ b/include/vhex/display/types.h
@@ -0,0 +1,7 @@
+#ifndef __VHEX_DISPLAY_TYPES__
+# define __VHEX_DISPLAY_TYPES__
+
+/* draw ID */
+typedef int did_t;
+
+#endif /* __VHEX_DISPLAY_TYPES__ */
diff --git a/include/vhex/driver.h b/include/vhex/driver.h
index 0d0c983..a6a318a 100644
--- a/include/vhex/driver.h
+++ b/include/vhex/driver.h
@@ -1,6 +1,7 @@
 #ifndef __VHEX_DRIVER__
 # define __VHEX_DRIVER__
 
+#include <vhex/defs/attributes.h>
 #include <vhex/defs/types.h>
 
 /* Device drivers */
@@ -31,7 +32,8 @@ struct vhex_driver
 	// Standard calls
 
 	/* Initialize the hardware for the driver to work in vhex. Usually
-	   installs interrupt handlers and configures registers. May be NULL. */
+	   installs interrupt handlers and configures registers. Cannot be
+	   NULL */
 	void (*configure)(void *state);
 
 	// Internal information
@@ -40,18 +42,20 @@ struct vhex_driver
 	uint16_t state_size;
 
 	/* default flags for the driver */
-	int default_flag;
-};
+	byte_union(flags,
+		uint8_t		:1;
+		uint8_t		:1;
+		uint8_t		:1;
+		uint8_t	DISPLAY	:1;
 
-enum {
-	/* Driver is used by default (will be configured) */
-	VHEX_DRV_USED	= 0x00,
+		uint8_t		:1;
+		uint8_t		:1;
+		uint8_t	SHARED	:1;
+		uint8_t	UNUSED	:1;
+	);
 
-	/* Driver is not used by the world */
-	VHEX_DRV_UNUSED	= 0x01,
-
-	/* Driver does not require hardware state saves during world switches */
-	VHEX_DRV_SHARED	= 0x02,
+	/* module related-internal data */
+	void *module_data;
 };
 
 
diff --git a/include/vhex/drivers/cpu.h b/include/vhex/driver/cpu.h
similarity index 100%
rename from include/vhex/drivers/cpu.h
rename to include/vhex/driver/cpu.h
diff --git a/include/vhex/drivers/mmu.h b/include/vhex/driver/mmu.h
similarity index 100%
rename from include/vhex/drivers/mmu.h
rename to include/vhex/driver/mmu.h
diff --git a/include/vhex/drivers/mpu/sh/sh7305/cpu.h b/include/vhex/driver/mpu/sh/sh7305/cpu.h
similarity index 100%
rename from include/vhex/drivers/mpu/sh/sh7305/cpu.h
rename to include/vhex/driver/mpu/sh/sh7305/cpu.h
diff --git a/include/vhex/drivers/mpu/sh/sh7305/intc.h b/include/vhex/driver/mpu/sh/sh7305/intc.h
similarity index 100%
rename from include/vhex/drivers/mpu/sh/sh7305/intc.h
rename to include/vhex/driver/mpu/sh/sh7305/intc.h
diff --git a/include/vhex/drivers/mpu/sh/sh7305/keysc.h b/include/vhex/driver/mpu/sh/sh7305/keysc.h
similarity index 100%
rename from include/vhex/drivers/mpu/sh/sh7305/keysc.h
rename to include/vhex/driver/mpu/sh/sh7305/keysc.h
diff --git a/include/vhex/drivers/mpu/sh/sh7305/mmu.h b/include/vhex/driver/mpu/sh/sh7305/mmu.h
similarity index 100%
rename from include/vhex/drivers/mpu/sh/sh7305/mmu.h
rename to include/vhex/driver/mpu/sh/sh7305/mmu.h
diff --git a/include/vhex/drivers/mpu/sh/sh7305/pfc.h b/include/vhex/driver/mpu/sh/sh7305/pfc.h
similarity index 100%
rename from include/vhex/drivers/mpu/sh/sh7305/pfc.h
rename to include/vhex/driver/mpu/sh/sh7305/pfc.h
diff --git a/include/vhex/driver/screen/r61524.h b/include/vhex/driver/screen/r61524.h
new file mode 100644
index 0000000..440ea96
--- /dev/null
+++ b/include/vhex/driver/screen/r61524.h
@@ -0,0 +1,52 @@
+#ifndef __VHEX_DRIVER_SCREEN_R61524__
+# define __VHEX_DRIVER_SCREEN_R61524__
+
+#include <vhex/defs/attributes.h>
+#include <vhex/defs/types.h>
+
+/* Registers and operations */
+enum {
+	device_code_read		= 0x000,
+	driver_output_control		= 0x001,
+	entry_mode			= 0x003,
+	display_control_2		= 0x008,
+	low_power_control		= 0x00b,
+
+	ram_address_horizontal		= 0x200,
+	ram_address_vertical		= 0x201,
+	write_data			= 0x202,
+
+	horizontal_ram_start		= 0x210,
+	horizontal_ram_end		= 0x211,
+	vertical_ram_start		= 0x212,
+	vertical_ram_end		= 0x213,
+};
+
+
+VINLINE static void r61524_select(uint16_t reg)
+{
+	/* Clear RS and write the register number */
+	*(volatile uint8_t *)0xa405013c &= ~0x10;
+	__asm__ volatile ("synco"::);
+	*(volatile uint16_t *)0xb4000000 = reg;
+	__asm__ volatile ("synco"::);
+
+	/* Set RS back. We don't do this in read()/write() because the display
+	   driver is optimized for consecutive GRAM access. LCD-transfers will
+	   be faster when executing select() followed by several calls to
+	   write(). (Although most applications should use the DMA instead.) */
+	*(volatile uint8_t *)0xa405013c |= 0x10;
+	__asm__ volatile ("synco"::);
+}
+
+VINLINE static uint16_t r61524_read(void)
+{
+	return *(volatile uint16_t *)0xb4000000;
+}
+
+VINLINE static void r61524_write(uint16_t data)
+{
+	*(volatile uint16_t *)0xb4000000 = data;
+}
+
+#endif /* __VHEX_DRIVER_SCREEN_R61524__ */
diff --git a/include/vhex/hypervisor.h b/include/vhex/hypervisor.h
index f35bdcc..8c9b62a 100644
--- a/include/vhex/hypervisor.h
+++ b/include/vhex/hypervisor.h
@@ -1,10 +1,7 @@
 #ifndef __VHEX_HYPERVISOR__
 # define __VHEX_HYPERVISOR__
 
-#include <stddef.h>
-#include <stdint.h>
-
-/* declare driver structure */
+#include <vhex/defs/attributes.h>
 #include <vhex/driver.h>
 
 /* real Vhex world with driver bitmap and meta information for the hypervisor */
@@ -12,49 +9,32 @@ struct vhex_world {
 	/* world driver information */
 	struct {
 		struct vhex_driver *context;
-		int flags;
+		byte_union(flags,
+			uint8_t			:1;
+			uint8_t			:1;
+			uint8_t			:1;
+			uint8_t			:1;
+
+			uint8_t			:1;
+			uint8_t	SHARED		:1;
+			uint8_t	INIT		:1;
+			uint8_t	UNUSED		:1;
+		);
 	} *driver;
 
 	/* internal information used by the hypervisor */
 	char const * name;
-	uint8_t status;
-};
+	byte_union(status,
+		uint8_t LOCKED	:1;
+		uint8_t ACTIVE	:1;
+		uint8_t 	:1;
+		uint8_t 	:1;
 
-/* define world status states */
-#define HYP_WORLD_STATUS_STATE_UNUSED		(1 << 0)
-#define HYP_WORLD_STATUS_STATE_UNINIT		(1 << 1)
-#define HYP_WORLD_STATUS_STATE_USED		(1 << 2)
-
-/* define world status flags */
-#define HYP_WORLD_STATUS_FLAG_UNDELETABLE	(1 << 0)
-
-/* hypervisor world status helper */
-
-#define HYP_WORLD_STATUS_SET(flags,state) \
-	(((flags & 0x0f) << 4) | ((state & 0x0f) << 0))
-
-#define HYP_WORLD_STATUS_SET_STATE(status, state)	\
-	do {					\
-		status &= 0x0f;				\
-		status |= (state & 0x0f) << 0;		\
-	} while (0);
-
-#define HYP_WORLD_STATUS_SET_FLAGS(status, flags)	\
-	do {					\
-		status &= 0xf0;				\
-		status |= (state & 0x0f) << 4;		\
-	} while (0);
-
-/* hypervisor world status getter */
-
-#define HYP_WORLD_STATUS_FLAGS(status)		((status & 0xf0) >> 4)
-#define HYP_WORLD_STATUS_STATE(status)		((status & 0x0f) >> 0)
-
-
-/* hypervisor driver status */
-enum {
-	HYP_WORLD_DRV_UNUSED	= VHEX_DRV_UNUSED,
-	HYP_WORLD_DRV_USED	= VHEX_DRV_USED,
+		uint8_t 	:1;
+		uint8_t 	:1;
+		uint8_t INIT	:1;
+		uint8_t USED	:1;
+	);
 };
 
 /* hyp_word_t : hypervisor world ID */
@@ -74,13 +54,10 @@ enum {
 };
 
 /* hypervisor_world_new() : create a new world with its name */
-extern hyp_world_t hypervisor_world_new(
-	char const * const restrict name,
-	int flags
-);
+extern hyp_world_t hypervisor_world_new(char const * const name);
 
 /* hypervisor_world_find() : find a world ID using its name */
-extern hyp_world_t hypervisor_world_find(char const * const restrict name);
+extern hyp_world_t hypervisor_world_find(char const * const name);
 
 /* hypervisor_world_get() : get a word using its ID */
 extern struct vhex_world *hypervisor_world_get(hyp_world_t id);
diff --git a/make/Makefile b/make/Makefile
index 68de480..025dbc5 100644
--- a/make/Makefile
+++ b/make/Makefile
@@ -146,7 +146,7 @@ define generate-target-lib
 #   Because we generate rule "on-the-fly" we need to create unique variable
 #  definition because make is not a "scoped" language. (therefore, when a
 #  variable is created, it will never be destroyed until the end of the script)
-t-$1-$2-build	:= $(VXSDK_BUILD_PREFIX)/$1/$2
+t-$1-$2-build	:= $(VXSDK_PREFIX_BUILD)/$1/$2
 
 # generate compilation flags
 
@@ -163,20 +163,6 @@ t-$1-$2-gcc-header	:= $$(t-$1-$2-gcc-base)/include
 t-$1-$2-cflags		+= -I../include -I.. -I$$(t-$1-$2-gcc-header)
 t-$1-$2-cflags		+= -L../lib -L.. -L$$(t-$1-$2-gcc-base)
 
-
-# generate format-specific flags
-
-t-$1-$2-exec		:=
-ifeq ($2,static)
-	t-$1-$2-exec	:= $1/libvhex-$1.a
-endif
-ifeq ($2,dynamic)
-	t-$1-$2-ldflags	+= -shared -T $1/$1.ld
-	t-$1-$2-ldflags	+= -soname=libvhex-$1-$(VXSDK_PKG_VERSION).so
-	t-$1-$2-ldflags	+= -Map=$$(t-$1-$2-build)/map
-	t-$1-$2-exec	:= $1/libvhex-$1.so
-endif
-
 # generate file's sources list, based on the configuration step
 
 t-$1-$2-dir	:= $$(foreach module,$$(CONFIG.$1.SRC-MODULE-PATH),\
@@ -186,6 +172,20 @@ t-$1-$2-src	:= $$(foreach path,$$(t-$1-$2-dir),\
 				$$(wildcard $$(path)/*.S) \
 				$$(wildcard $$(path)/*.s))
 
+# generate format-specific flags
+
+t-$1-$2-exec		:=
+ifeq ($2,static)
+t-$1-$2-exec	:= $1/libvhex-$1.a
+endif
+ifeq ($2,dynamic)
+t-$1-$2-ldflags	+= -shared
+t-$1-$2-ldflags	+= -soname=libvhex-$1-$(VXSDK_PKG_VERSION).so
+t-$1-$2-ldflags	+= -Map=$$(t-$1-$2-build)/map
+t-$1-$2-exec	:= $1/libvhex-$1.so
+t-$1-$2-src	:= $(wildcard ../fake/*.c)
+endif
+
 # generate file's compilation rules and all object filename into an  object
 # list variable, this will be used by the `main` rule
 
@@ -208,7 +208,7 @@ $$(t-$1-$2-exec): $$(t-$1-$2-obj)
 	@ mkdir -p $$(dir $$@)
 	@ printf "$(blue)Create the library $(red)$$@$(nocolor)\n"
 ifeq ($2,dynamic)
-	$$(t-$1-$2-gcc) -shared $$(t-$1-$2-gcc-libs) -o $$@ $$^
+	$$(t-$1-$2-gcc) -shared $$(t-$1-$2-cflags) $$(t-$1-$2-gcc-libs) -o $$@ $$^
 else
 	$$(t-$1-$2-ar) crs $$@ $$^
 endif
@@ -252,12 +252,12 @@ define generate-install-rule
 
 # Generate the installation rule
 $(basename $(notdir $1))-install:
-	install -d $(VXSDK_LIB_PREFIX)
-	install $1 -m 644 $(VXSDK_LIB_PREFIX)
+	install -d $(VXSDK_PREFIX_LIB)
+	install $1 -m 644 $(VXSDK_PREFIX_LIB)
 
 # Generate the uninstallation rule
 $(basename $(notdir $1))-uninstall:
-	rm -f $(VXSDK_LIB_PREFIX)/$(notdir $1)
+	rm -f $(VXSDK_PREFIX_LIB)/$(notdir $1)
 
 # Register generated rules into their appropriate list
 $2	+= $(basename $(notdir $1))-install
@@ -272,11 +272,12 @@ endef
 define generate-board-install-rule
 
 $1-install:
-	install -d $(VXSDK_LIB_PREFIX)
-	install ../board/$(strip $1)/$(strip $1).ld -m 644 $(VXSDK_LIB_PREFIX)
+	install -d $(VXSDK_PREFIX_LIB)
+	install ../board/$(strip $1)/*.ld -m 644 $(VXSDK_PREFIX_LIB)
 
 $1-uninstall:
-	rm -f  $(VXSDK_LIB_PREFIX)/$(strip $1).ld
+	rm -f  $(VXSDK_PREFIX_LIB)/$(strip $1).ld
+	rm -f  $(VXSDK_PREFIX_LIB)/$(strip $1)-dynamic.ld
 
 $2	+= $1-install
 $3	+= $1-uninstall
@@ -303,7 +304,7 @@ $(foreach board,$(CONFIG.BOARD-LIST),$(eval \
 ))
 
 # Generate the path where include directory will be installed.
-target-install-hdr-dir		:= $(VXSDK_LIB_PREFIX)/include/
+target-install-hdr-dir		:= $(VXSDK_PREFIX_LIB)/include/
 ifeq ($(wildcard $(target-install-header-dir)vhex/.*),)
 	target-install-hdr-dir	:= $(target-install-hdr-dir)vhex
 endif
@@ -314,10 +315,11 @@ endif
 # Installation rules
 #---
 install: $(target-install-rules)
+	mkdir -p $(dir $(target-install-hdr-dir))
 	cp -r ../include/vhex $(target-install-hdr-dir)
 
 unsintall: $(target-uninstall_rules)
-	rm -rf $(VXSDK_LIB_PREFIX)/include/vhex
+	rm -rf $(VXSDK_PREFIX_LIB)/include/vhex
 
 .PHONY: install uninstall
 
diff --git a/src/drivers/mpu/sh/sh7305/cpu/atomic.c b/src/drivers/mpu/sh/sh7305/cpu/atomic.c
index 4945053..55202f6 100644
--- a/src/drivers/mpu/sh/sh7305/cpu/atomic.c
+++ b/src/drivers/mpu/sh/sh7305/cpu/atomic.c
@@ -1,5 +1,5 @@
-#include <vhex/drivers/cpu.h>
-#include <vhex/drivers/mpu/sh/sh7305/cpu.h>
+#include <vhex/driver/cpu.h>
+#include <vhex/driver/mpu/sh/sh7305/cpu.h>
 
 /* Value of IMASK when atomic mode is entered */
 static int saved_IMASK = 0;
diff --git a/src/drivers/mpu/sh/sh7305/cpu/cpu.c b/src/drivers/mpu/sh/sh7305/cpu/cpu.c
index 9574130..56053ed 100644
--- a/src/drivers/mpu/sh/sh7305/cpu/cpu.c
+++ b/src/drivers/mpu/sh/sh7305/cpu/cpu.c
@@ -1,5 +1,5 @@
-#include "vhex/driver.h"
-#include "vhex/drivers/mpu/sh/sh7305/cpu.h"
+#include <vhex/driver.h>
+#include <vhex/driver/mpu/sh/sh7305/cpu.h>
 
 #include <string.h>
 
@@ -32,12 +32,12 @@ static void __cpu_configure(struct cpu_ctx *state)
 	/* configure the Status Register
 	    <> force the privileged mode
 	    <> enable DSP
-	    <> allow interruptions */
+	    <> mask interruptions (it will be unmasked in <hypervisor/switch>)*/
 	state->sr.MD  = 1;
 	state->sr.RB  = 0;
 	state->sr.BL  = 0;
 	state->sr.DSP = 1;
-	state->sr.IMASK = 0b0000;
+	state->sr.IMASK = 0b1111;
 }
 
 /* hardware hypervisor call */
@@ -67,4 +67,4 @@ struct vhex_driver drv_cpu = {
 	.configure  = (void*)&__cpu_configure,
 	.state_size = sizeof(struct cpu_ctx)
 };
-VHEX_DECLARE_DRIVER(16, drv_cpu);
+VHEX_DECLARE_DRIVER(02, drv_cpu);
diff --git a/src/drivers/mpu/sh/sh7305/intc/install.c b/src/drivers/mpu/sh/sh7305/intc/install.c
index d42fcd7..0bd5b6e 100644
--- a/src/drivers/mpu/sh/sh7305/intc/install.c
+++ b/src/drivers/mpu/sh/sh7305/intc/install.c
@@ -1,4 +1,4 @@
-#include <vhex/drivers/mpu/sh/sh7305/intc.h>
+#include <vhex/driver/mpu/sh/sh7305/intc.h>
 #include <vhex/defs/types.h>
 #include <string.h>
 
diff --git a/src/drivers/mpu/sh/sh7305/intc/intc.c b/src/drivers/mpu/sh/sh7305/intc/intc.c
index 4bdf86e..3ec28ac 100644
--- a/src/drivers/mpu/sh/sh7305/intc/intc.c
+++ b/src/drivers/mpu/sh/sh7305/intc/intc.c
@@ -1,5 +1,5 @@
-#include "vhex/driver.h"
-#include "vhex/drivers/mpu/sh/sh7305/intc.h"
+#include <vhex/driver.h>
+#include <vhex/driver/mpu/sh/sh7305/intc.h>
 
 #include <string.h>
 
diff --git a/src/drivers/mpu/sh/sh7305/keysc/handler.c b/src/drivers/mpu/sh/sh7305/keysc/handler.c
index 5f99c5b..ed1964b 100644
--- a/src/drivers/mpu/sh/sh7305/keysc/handler.c
+++ b/src/drivers/mpu/sh/sh7305/keysc/handler.c
@@ -1,6 +1,6 @@
 #include <vhex/keyboard.h>
-#include <vhex/drivers/mpu/sh/sh7305/keysc.h>
-#include <vhex/drivers/mpu/sh/sh7305/intc.h>
+#include <vhex/driver/mpu/sh/sh7305/keysc.h>
+#include <vhex/driver/mpu/sh/sh7305/intc.h>
 
 /* Internal indicator used by high-level function to notice when the key list
    is updated */
diff --git a/src/drivers/mpu/sh/sh7305/keysc/keysc.c b/src/drivers/mpu/sh/sh7305/keysc/keysc.c
index 07c23e6..a9e780d 100644
--- a/src/drivers/mpu/sh/sh7305/keysc/keysc.c
+++ b/src/drivers/mpu/sh/sh7305/keysc/keysc.c
@@ -1,6 +1,6 @@
-#include "vhex/drivers/mpu/sh/sh7305/keysc.h"
-#include "vhex/drivers/mpu/sh/sh7305/intc.h"
-#include "vhex/driver.h"
+#include <vhex/driver/mpu/sh/sh7305/keysc.h>
+#include <vhex/driver/mpu/sh/sh7305/intc.h>
+#include <vhex/driver.h>
 
 /* define the private KeyScan context structure */
 struct keysc_ctx {
diff --git a/src/drivers/mpu/sh/sh7305/mmu/utlb.c b/src/drivers/mpu/sh/sh7305/mmu/utlb.c
index b5c92be..638e628 100644
--- a/src/drivers/mpu/sh/sh7305/mmu/utlb.c
+++ b/src/drivers/mpu/sh/sh7305/mmu/utlb.c
@@ -1,8 +1,8 @@
 //---
 //	vhex:mmu:mmu - MMU driver definition and context management
 //---
-#include <vhex/drivers/mmu.h>
-#include <vhex/drivers/mpu/sh/sh7305/mmu.h>
+#include <vhex/driver/mmu.h>
+#include <vhex/driver/mpu/sh/sh7305/mmu.h>
 #include <vhex/defs/attributes.h>
 
 /* utlb_addr() - get the P4 address of a UTLB address entry */
diff --git a/src/drivers/screen/R61524/r61524.c b/src/drivers/screen/R61524/r61524.c
index dbd7107..6cc3a00 100644
--- a/src/drivers/screen/R61524/r61524.c
+++ b/src/drivers/screen/R61524/r61524.c
@@ -1,15 +1,167 @@
-#if 0
+#include <vhex/defs/types.h>
+#include <vhex/driver.h>
+#include <vhex/driver/screen/r61524.h>
+#include <vhex/display/stack.h>
+
+//---
+// R61524 driver API
+//---
+
+/* r61524_clear_surface() - optimal way to clear the draw and render surface */
+VINLINE void r61524_clear_surface(struct dshader_surface *surface)
+{
+	//TODO: check cache behaviour:
+	//  > full xram then yram
+	//  > xram and yram
+	//  > yram and xram
+	//  > restrict / non-restrict
+	uint32_t * restrict xram = surface->draw;
+	uint32_t * restrict yram = surface->frag;
+	for (int i = 0; i < 2048; ++i) {
+		xram[i] = 0x00010001;
+		yram[i] = 0x00000000;
+	}
+}
+
+/* r61524_frame_start() - prepar the screen and reset surfaces */
+int r61524_frame_start(struct dshader_surface *surface)
+{
+	/* Set the windows size */
+	r61524_select(horizontal_ram_start);
+	r61524_write(0);
+	r61524_select(horizontal_ram_end);
+	r61524_write(395);
+	r61524_select(vertical_ram_start);
+	r61524_write(0);
+	r61524_select(vertical_ram_end);
+	r61524_write(223);
+
+	/* Set the RAM position */
+	r61524_select(ram_address_horizontal);
+	r61524_write(0);
+	r61524_select(ram_address_vertical);
+	r61524_write(0);
+
+	/* Bind address 0xb4000000 to the data write command */
+	r61524_select(write_data);
+
+	/* initialize surface information */
+	surface->draw = (void*)0xe5007000;
+	surface->frag = (void*)0xe5017000;
+	surface->width = 396;
+	surface->height = 10;
+	surface->x = 0;
+	surface->y = 0;
+
+	/* reset the two surfaces */
+	r61524_clear_surface(surface);
+	return (0);
+}
+
+int r61524_frame_frag_next(struct dshader_surface *surface)
+{
+	surface->y += 10;
+	if (surface->y >= 224) {
+		surface->y -= 10;
+		return (-1);
+	}
+	r61524_clear_surface(surface);
+	return (0);
+}
+
+int r61524_frame_frag_send(struct dshader_surface *surface)
+{
+	//TODO: assembly
+	//TODO: check cache behaviour:
+	//  > full xram then yram
+	//  > xram and yram
+	//  > yram and xram
+	//  > restrict / non-restrict
+	uint16_t pixel;
+	uint16_t * restrict xram = surface->draw;
+	uint16_t * restrict yram = surface->frag;
+	for (int i = 0; i < 4096; ++i) {
+		pixel = xram[i];
+		if (pixel & 0x0001) {
+			r61524_write(yram[i]);
+			continue;
+		}
+		r61524_write((pixel & 0xffc0) | ((pixel & 0x003e) >> 1));
+	}
+	return (0);
+}
+
+int r61524_frame_end(struct dshader_surface *surface)
+{
+	(void)surface;
+	return (0);
+}
+
+//---
+// Driver definition
+//---
+
+/* R61524 display (graphics RAM range) */
+struct r61524_ctx {
+	uint16_t HSA;
+	uint16_t HEA;
+	uint16_t VSA;
+	uint16_t VEA;
+};
+
+static void __r61524_configure(struct r61524_ctx *s)
+{
+	s->HSA = 0;
+	s->HEA = 395;
+	s->VSA = 0;
+	s->VEA = 223;
+}
+
+static void __r61524_hsave(struct r61524_ctx *s)
+{
+	r61524_select(horizontal_ram_start);
+	s->HSA = r61524_read();
+	r61524_select(horizontal_ram_end);
+	s->HEA = r61524_read();
+
+	r61524_select(vertical_ram_start);
+	s->VSA = r61524_read();
+	r61524_select(vertical_ram_end);
+	s->VEA = r61524_read();
+}
+
+static void __r61524_hrestore(struct r61524_ctx const *s)
+{
+	r61524_select(horizontal_ram_start);
+	r61524_write(s->HSA);
+	r61524_select(horizontal_ram_end);
+	r61524_write(s->HEA);
+
+	r61524_select(vertical_ram_start);
+	r61524_write(s->VSA);
+	r61524_select(vertical_ram_end);
+	r61524_write(s->VEA);
+}
 
 
-
-/* declare the CPU driver */
+static struct dstack_drv_interface drv_r61524_dstack = {
+	.frame_start     = &r61524_frame_start,
+	.frame_frag_next = &r61524_frame_frag_next,
+	.frame_frag_send = &r61524_frame_frag_send,
+	.frame_end       = &r61524_frame_end
+};
 
 struct vhex_driver drv_r61524 = {
 	.name       = "R61524",
 	.hsave      = (void*)&__r61524_hsave,
 	.hrestore   = (void*)&__r61524_hrestore,
 	.configure  = (void*)&__r61524_configure,
-	.state_size = sizeof(struct r61524_ctx)
+	.state_size = sizeof(struct r61524_ctx),
+	.flags = {
+		.DISPLAY = 1,
+		.SHARED  = 0,
+		.UNUSED  = 0,
+	},
+	.module_data = &drv_r61524_dstack
 };
 VHEX_DECLARE_DRIVER(16, drv_r61524);
-#endif
diff --git a/src/kernel/exch.c b/src/kernel/exch.c
index d8e6cfe..61c6442 100644
--- a/src/kernel/exch.c
+++ b/src/kernel/exch.c
@@ -4,6 +4,7 @@
 //TODO: add relocation information
 void vhex_kernel_exch_panic(void)
 {
+#if 0
 	extern uint16_t vhex_vram[];
 	uint32_t PC;
 	uint32_t TEA;
@@ -50,6 +51,7 @@ void vhex_kernel_exch_panic(void)
 	dtext(6, 108, C_BLACK, "Please press the RESET button to restart the");
 	dtext(6, 121, C_BLACK, "calculator.");
 	dupdate();
+#endif
 
 	while (1) { __asm__ volatile ("sleep"); }
 }
diff --git a/src/modules/display/dclear.c b/src/modules/display/dclear.c
index 043884f..5cf68fb 100644
--- a/src/modules/display/dclear.c
+++ b/src/modules/display/dclear.c
@@ -1,13 +1,24 @@
-#include <vhex/display.h>
-#include <vhex/defs/attributes.h>
 #include <vhex/defs/types.h>
+#include <vhex/display.h>
+#include <vhex/display/stack.h>
 
-/* expose Video RAM */
-extern uint16_t vhex_vram[];
+/* dclear_draw() : real drawing algorithm */
+static void dclear_draw(
+	struct dshader_surface *surface,
+	dshader_call_arg_t *arg
+)
+{
+	uint32_t * restrict vram;
+	uint32_t color;
+
+	vram = surface->frag;
+	color = arg[0].u16 & 0xffff;
+	for (int i = 0; i < 2048; ++i)
+		vram[i] = (color << 16) | (color << 0);
+}
 
 /* dclear(): Fill the screen with a single color */
-VWEAK void dclear(int color)
+did_t dclear(int color)
 {
-	for (int i = 0; i < 396 * 224 ; ++i)
-		vhex_vram[i] = color;
+	return dstack_add_action(&DSTACK_CALL(&dclear_draw, color), NULL);
 }
diff --git a/src/modules/display/display.c b/src/modules/display/display.c
index 90816df..fc94a84 100644
--- a/src/modules/display/display.c
+++ b/src/modules/display/display.c
@@ -1,4 +1,4 @@
-#include "vhex/display.h"
+#include "vhex/display/stack.h"
 #include "vhex/module.h"
 
 /* module init */
@@ -6,13 +6,18 @@
 /* __display_init() : initialize the display */
 static void __display_init(void)
 {
-	/* Nothing to do here ? */
+	struct dstack_config conf = {
+		.default_icall_pool_slot   = DSTACK_DEFAULT_ICALL_SLOT,
+		.default_icall_args_nb     = DSTACK_DEFAULT_ICALL_ARGS,
+		.default_shader_per_action = DSTACK_DEFAULT_SHADER_PER_ACTION
+	};
+	dstack_init(&conf);
 }
 
 /* __display_quit() : uninit the display */
 static void __display_quit(void)
 {
-	/* Nothing to do here ? */
+	dstack_quit();
 }
 
 /* declare the display module */
diff --git a/src/modules/display/dhline.c b/src/modules/display/draw/dhline.c
similarity index 100%
rename from src/modules/display/dhline.c
rename to src/modules/display/draw/dhline.c
diff --git a/src/modules/display/dline.c b/src/modules/display/draw/dline.c
similarity index 100%
rename from src/modules/display/dline.c
rename to src/modules/display/draw/dline.c
diff --git a/src/modules/display/dpixel.c b/src/modules/display/draw/dpixel.c
similarity index 100%
rename from src/modules/display/dpixel.c
rename to src/modules/display/draw/dpixel.c
diff --git a/src/modules/display/drect.c b/src/modules/display/draw/drect.c
similarity index 100%
rename from src/modules/display/drect.c
rename to src/modules/display/draw/drect.c
diff --git a/src/modules/display/dstack.c b/src/modules/display/dstack.c
new file mode 100644
index 0000000..425ef2f
--- /dev/null
+++ b/src/modules/display/dstack.c
@@ -0,0 +1,148 @@
+#include <vhex/display/stack.h>
+#include <vhex/display/shader.h>
+#include <vhex/driver.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+static struct {
+	struct {
+		struct dstack_action *action;
+		int slots;
+		int idx;
+	} pool;
+	struct dstack_drv_interface driver;
+} dstack_info = {
+	.pool = {
+		.action = NULL,
+		.slots = 0,
+		.idx = 0
+	},
+	.driver = {
+		.frame_start = NULL,
+		.frame_frag_next = NULL,
+		.frame_frag_send = NULL,
+		.frame_end = NULL,
+	}
+};
+
+//
+// Kernel API
+//
+
+/* dstack_init() : Initialise the draw stack (should not be involved) */
+//TODO: safe
+int dstack_init(struct dstack_config *config)
+{
+	dstack_info.pool.action = calloc(
+		config->default_icall_pool_slot,
+		sizeof(dstack_call_t)
+	);
+	dstack_info.pool.slots = config->default_icall_pool_slot;
+	dstack_info.pool.idx = -1;
+	for (int i = 0; i < dstack_info.pool.slots; ++i) {
+		dstack_info.pool.action[i].shader.table = malloc(
+			config->default_shader_per_action
+		);
+		dstack_info.pool.action[i].shader.number =
+					config->default_shader_per_action;
+		dstack_info.pool.action[i].shader.idx = 0;
+	}
+
+	struct vhex_driver *driver = vhex_driver_table();
+	for (int i = 0; i < vhex_driver_count(); ++i) {
+		if (driver[i].flags.DISPLAY) {
+			memcpy(
+				&dstack_info.driver,
+				driver[i].module_data,
+				sizeof(struct dstack_drv_interface)
+			);
+			break;
+		}
+	}
+}
+
+/* dstack_quit() : Uninit the draw stack */
+int dstack_quit(void)
+{
+	for (int i = 0; i < dstack_info.pool.slots; ++i) {
+		free(dstack_info.pool.action[i].shader.table);
+		dstack_info.pool.action[i].shader.number = 0;
+		dstack_info.pool.action[i].shader.idx = 0;
+	}
+}
+
+
+//
+// Internal API
+//
+
+static did_t dstack_action_alloc(dstack_call_t *call, dshader_call_t *shader)
+{
+	struct dstack_action *action;
+	int i;
+
+	dstack_info.pool.idx += 1;
+	if (dstack_info.pool.idx >= dstack_info.pool.slots) {
+		dstack_info.pool.slots += dstack_info.pool.slots;
+		dstack_info.pool.action = realloc(
+			dstack_info.pool.action,
+			dstack_info.pool.slots
+		);
+	}
+	action = &dstack_info.pool.action[dstack_info.pool.idx];
+	memcpy(&action->call, call, sizeof(dstack_call_t));
+	if (shader != NULL) {
+		for (i = 0; shader[i].routine != NULL; ++i) {
+			if (i >= action->shader.number) {
+				action->shader.number += action->shader.number;
+				action->shader.table = realloc(
+					action->shader.table,
+					action->shader.number
+				);
+			}
+			memcpy(
+				&action->shader.table[i],
+				&shader[i],
+				sizeof(dshader_call_t)
+			);
+		}
+	}
+	action->shader.idx = i;
+	return dstack_info.pool.idx;
+}
+
+//
+// Public API
+//
+
+/* dstack_add_action() : add a new action in the draw stack */
+did_t dstack_add_action(dstack_call_t *call, dshader_call_t *shader)
+{
+	return dstack_action_alloc(call, shader);
+}
+
+/* dstack_render(): render a frame */
+void dstack_render(void)
+{
+	struct dshader_surface surface;
+	struct dstack_action *action;
+
+	action = dstack_info.pool.action;
+	dstack_info.driver.frame_start(&surface);
+	do {
+		for (int i = 0; i <= dstack_info.pool.idx; ++i) {
+			action[i].call.routine(&surface, action[i].call.args);
+			for (int j = 0; j < action[i].shader.idx; j++) {
+				action[i].shader.table[j].routine(
+					&surface,
+					action[i].call.args,
+					action[i].shader.table[i].args
+				);
+			}
+		}
+		dstack_info.driver.frame_frag_send(&surface);
+	} while (dstack_info.driver.frame_frag_next(&surface) == 0);
+	dstack_info.driver.frame_end(&surface);
+	dstack_info.pool.idx = 0;
+}
diff --git a/src/modules/display/dupdate.c b/src/modules/display/dupdate.c
index be91bad..dac2838 100644
--- a/src/modules/display/dupdate.c
+++ b/src/modules/display/dupdate.c
@@ -1,76 +1,8 @@
 #include "vhex/display.h"
-#include "vhex/defs/attributes.h"
-#include "vhex/defs/types.h"
-
-/* Registers and operations */
-enum {
-	device_code_read		= 0x000,
-	driver_output_control		= 0x001,
-	entry_mode			= 0x003,
-	display_control_2		= 0x008,
-	low_power_control		= 0x00b,
-
-	ram_address_horizontal		= 0x200,
-	ram_address_vertical		= 0x201,
-	write_data			= 0x202,
-
-	horizontal_ram_start		= 0x210,
-	horizontal_ram_end		= 0x211,
-	vertical_ram_start		= 0x212,
-	vertical_ram_end		= 0x213,
-};
-
-/* Interface with the controller */
-static volatile uint16_t *intf = (void *)0xb4000000;
-/* Bit 4 of Port R controls the RS bit of the display driver */
-static volatile uint8_t *PRDR = (void *)0xa405013c;
-
-static void select(uint16_t reg)
-{
-	/* Clear RS and write the register number */
-	*PRDR &= ~0x10;
-	__asm__ volatile ("synco"::);
-	*intf = reg;
-	__asm__ volatile ("synco"::);
-
-	/* Set RS back. We don't do this in read()/write() because the display
-	   driver is optimized for consecutive GRAM access. LCD-transfers will
-	   be faster when executing select() followed by several calls to
-	   write(). (Although most applications should use the DMA instead.) */
-	*PRDR |= 0x10;
-	__asm__ volatile ("synco"::);
-}
-
-static void write(uint16_t data)
-{
-	*intf = data;
-}
+#include "vhex/display/stack.h"
 
 /* dupdate(): Push the video RAM to the display driver */
-VWEAK void dupdate(void)
+void dupdate(void)
 {
-	extern uint16_t vhex_vram[];
-
-	/* Set the windows size */
-	select(horizontal_ram_start);
-	write(0);
-	select(horizontal_ram_end);
-	write(395);
-	select(vertical_ram_start);
-	write(0);
-	select(vertical_ram_end);
-	write(223);
-
-	/* Set the RAM position */
-	select(ram_address_horizontal);
-	write(0);
-	select(ram_address_vertical);
-	write(0);
-
-	/* Bind address 0xb4000000 to the data write command */
-	select(write_data);
-
-	/* force-fill manualy the screen */
-	for (int i = 0; i < 396 * 224; ++i)
-		write(vhex_vram[i]);
+	dstack_render();
 }
diff --git a/src/modules/display/dascii.c b/src/modules/display/text/dascii.c
similarity index 98%
rename from src/modules/display/dascii.c
rename to src/modules/display/text/dascii.c
index 5b7d547..071e8c6 100644
--- a/src/modules/display/dascii.c
+++ b/src/modules/display/text/dascii.c
@@ -1,3 +1,4 @@
+#if 0
 #include "vhex/display.h"
 #include "vhex/defs/types.h"
 
@@ -38,3 +39,4 @@ void dascii(int x, int y, int fg, int bg, int n)
 		}
 	}
 }
+#endif
diff --git a/src/modules/display/dtext.c b/src/modules/display/text/dtext.c
similarity index 98%
rename from src/modules/display/dtext.c
rename to src/modules/display/text/dtext.c
index 35ce30d..90be2d1 100644
--- a/src/modules/display/dtext.c
+++ b/src/modules/display/text/dtext.c
@@ -1,3 +1,4 @@
+#if 0
 #include "vhex/display.h"
 #include "vhex/defs/types.h"
 
@@ -55,3 +56,4 @@ void dprint(int x, int y, int fg, char const * const text, ...)
 
 	dtext_opt(x, y, fg, C_NONE, DTEXT_LEFT, DTEXT_TOP, buff, -1);
 }
+#endif
diff --git a/src/modules/display/dsize.c b/src/modules/display/text/dtext_size.c
similarity index 98%
rename from src/modules/display/dsize.c
rename to src/modules/display/text/dtext_size.c
index a01de3b..a84dbea 100644
--- a/src/modules/display/dsize.c
+++ b/src/modules/display/text/dtext_size.c
@@ -1,3 +1,4 @@
+#if 0
 #include <vhex/display.h>
 #include <vhex/defs/types.h>
 
@@ -28,3 +29,4 @@ void dnsize(char const *str, int n, int *w, int *h)
 	if (w != NULL) *w = strnlen(str, n) * (font8x9.width + 1);
 	if (h != NULL) *h = font8x9.height;
 }
+#endif
diff --git a/src/modules/hypervisor/switch.c b/src/modules/hypervisor/switch.c
index ec83296..1775a12 100644
--- a/src/modules/hypervisor/switch.c
+++ b/src/modules/hypervisor/switch.c
@@ -1,6 +1,5 @@
 #include <vhex/hypervisor.h>
-#include <vhex/drivers/cpu.h>
-
+#include <vhex/driver/cpu.h>
 #include <vhex/display.h>
 
 /* hypervisor_world_switch() : perform a world switch */
@@ -11,7 +10,6 @@ int hypervisor_world_switch(hyp_world_t out, hyp_world_t in)
 	struct vhex_world *wout;
 	struct vhex_driver *dtable;
 
-
 	wout = hypervisor_world_get(out);
 	win = hypervisor_world_get(in);
 	if (wout == NULL || win == NULL)
@@ -24,29 +22,33 @@ int hypervisor_world_switch(hyp_world_t out, hyp_world_t in)
 	for (int i = 0; i < vhex_driver_count(); ++i) {
 		if (dtable[i].hpowered != NULL
 				&& dtable[i].hpowered() == false) {
-			wout->driver[i].flags = HYP_WORLD_DRV_UNUSED;
+			wout->driver[i].flags.UNUSED = 1;
 			continue;
 		}
 		dtable[i].hsave(wout->driver[i].context);
-		wout->driver[i].flags = HYP_WORLD_DRV_USED;
+		wout->driver[i].flags.UNUSED = 0;
 	}
 	for (int i = 0; i < vhex_driver_count(); ++i) {
-		if (HYP_WORLD_STATUS_STATE(win->status)
-				== HYP_WORLD_STATUS_STATE_UNINIT) {
-			if (dtable[i].configure != NULL)
-				dtable[i].configure(win->driver[i].context);
-			win->driver[i].flags = dtable[i].default_flag;
+		if (win->status.INIT == 0) {
+			dtable[i].configure(win->driver[i].context);
+			win->driver[i].flags.UNUSED = dtable[i].flags.UNUSED;
+			win->driver[i].flags.SHARED = dtable[i].flags.SHARED;
 		}
-		if (win->driver[i].flags == HYP_WORLD_DRV_UNUSED) {
+		//FIXME : check shared driver
+		if (win->driver[i].flags.UNUSED == 1) {
 			if (dtable[i].hpowered() == true)
 				dtable[i].hpoweroff();
 			continue;
 		}
+		//FIXME : check if the driver is unused
 		if (dtable[i].hpowered != NULL && dtable[i].hpowered() == false)
 			dtable[i].hpoweron();
 		dtable[i].hrestore(win->driver[i].context);
+
 	}
-	HYP_WORLD_STATUS_SET_STATE(win->status, HYP_WORLD_STATUS_STATE_USED);
-	HYP_WORLD_STATUS_SET_STATE(wout->status, HYP_WORLD_STATUS_STATE_USED);
+	win->status.INIT = 1;
+	win->status.ACTIVE = 1;
+	wout->status.ACTIVE = 0;
+	wout->status.INIT = 1;
 	cpu_atomic_end();
 }
diff --git a/src/modules/hypervisor/table.c b/src/modules/hypervisor/table.c
index 5f983c8..2dda775 100644
--- a/src/modules/hypervisor/table.c
+++ b/src/modules/hypervisor/table.c
@@ -8,68 +8,73 @@
 
 /* internal world table */
 static struct {
-	struct vhex_world *table;
-	size_t table_slot;
+	struct {
+		struct vhex_world *table;
+		int number;
+	} world;
 } hyp = {
-	.table = NULL,
-	.table_slot = 0
+	.world = {
+		.table = NULL,
+		.number = 0
+	}
 };
 
 /* hypervisor_world_new() : create a new world with its name */
-hyp_world_t hypervisor_world_new(char const * const restrict name, int flags)
+hyp_world_t hypervisor_world_new(char const * const restrict name)
 {
 	struct vhex_driver *dtable;
 	hyp_world_t id;
 
 	/* try to find free world */
-	id = 0xb0cad0;
-	if (hyp.table != NULL) {
-		for (size_t i = 0; i < hyp.table_slot; ++i) {
-			if (HYP_WORLD_STATUS_STATE(hyp.table[i].status)
-					== HYP_WORLD_STATUS_STATE_UNUSED) {
-				id = i;
-				continue;
-			}
-			if (strcmp(hyp.table[i].name, name) == 0)
-				return (hyp_world_already_exists);
-
+	id = -1;
+	for (int i = 0; i < hyp.world.number; ++i) {
+		if (hyp.world.table[i].status.USED == 0) {
+			id = i;
+			continue;
 		}
+		if (strcmp(hyp.world.table[i].name, name) == 0)
+			return (hyp_world_already_exists);
 	}
 
 	/* if no world is found, update the table */
-	if (id == 0xb0cad0) {
-		id = hyp.table_slot;
+	if (id == -1) {
+		id = hyp.world.number;
 
-		if (hyp.table_slot == 0)
-			hyp.table_slot = 1;
+		hyp.world.number += hyp.world.number;
+		if (hyp.world.number == 0)
+			hyp.world.number = 2;
 
-		hyp.table = reallocarray(
-			hyp.table,
-			hyp.table_slot * 2,
+		hyp.world.table = reallocarray(
+			hyp.world.table,
+			hyp.world.number,
 			sizeof(struct vhex_world)
 		);
-		for (size_t i = hyp.table_slot; i < hyp.table_slot * 2; ++i) {
-			hyp.table[i].status = HYP_WORLD_STATUS_STATE_UNUSED;
-			hyp.table[i].driver = NULL;
-			hyp.table[i].name = NULL;
-		}
 
-		hyp.table_slot = hyp.table_slot * 2;
+		for (int i = id; i < hyp.world.number; ++i) {
+			hyp.world.table[i].driver = NULL;
+			hyp.world.table[i].name = NULL;
+			hyp.world.table[id].status.LOCKED = 0;
+			hyp.world.table[id].status.ACTIVE = 0;
+			hyp.world.table[id].status.INIT   = 0;
+			hyp.world.table[id].status.USED   = 0;
+		}
 	}
 
 	/* initialize the world */
-	hyp.table[id].name = strdup(name);
-	hyp.table[id].status = HYP_WORLD_STATUS_SET(
-		flags,
-		HYP_WORLD_STATUS_STATE_UNINIT
-	);
-	if (hyp.table[id].driver == NULL) {
-		hyp.table[id].driver = malloc(
-			vhex_driver_count() * sizeof(*hyp.table[id].driver)
+	hyp.world.table[id].name = strdup(name);
+	hyp.world.table[id].status.LOCKED = 0;
+	hyp.world.table[id].status.ACTIVE = 0;
+	hyp.world.table[id].status.INIT   = 0;
+	hyp.world.table[id].status.USED   = 1;
+
+	if (hyp.world.table[id].driver == NULL) {
+		hyp.world.table[id].driver = calloc(
+			vhex_driver_count(),
+			sizeof(*hyp.world.table[id].driver)
 		);
 		dtable = vhex_driver_table();
 		for (int i = 0; i < vhex_driver_count(); ++i) {
-			hyp.table[id].driver[i].context = malloc(
+			hyp.world.table[id].driver[i].context = malloc(
 				dtable[i].state_size
 			);
 		}
@@ -82,9 +87,9 @@ hyp_world_t hypervisor_world_new(char const * const restrict name, int flags)
 /* hypervisor_world_find() : find a world using its name */
 hyp_world_t hypervisor_world_find(char const * const restrict name)
 {
-	if (hyp.table != NULL) {
-		for (size_t i = 0; i < hyp.table_slot; ++i) {
-			if (strcmp(hyp.table[i].name, name) == 0)
+	if (hyp.world.table != NULL) {
+		for (int i = 0; i < hyp.world.number; ++i) {
+			if (strcmp(hyp.world.table[i].name, name) == 0)
 				return (i);
 		}
 	}
@@ -94,26 +99,23 @@ hyp_world_t hypervisor_world_find(char const * const restrict name)
 /* hypervisor_world_get() : get a word using its ID */
 struct vhex_world *hypervisor_world_get(hyp_world_t id)
 {
-	if (id < 0 || (size_t)id >= hyp.table_slot)
+	if (id < 0 || id >= hyp.world.number)
 		return (NULL);
-	if (HYP_WORLD_STATUS_STATE(hyp.table[id].status)
-			== HYP_WORLD_STATUS_STATE_UNUSED) {
+	if (hyp.world.table[id].status.USED == 0) {
 		return (NULL);
 	}
-	return (&hyp.table[id]);
+	return (&hyp.world.table[id]);
 }
 
 
 /* hypervisor_world_delete() : remove world */
 hyp_world_t hypervisor_world_delete(hyp_world_t id)
 {
-	if (id < 0 || (size_t)id >= hyp.table_slot)
+	if (id < 0 || id >= hyp.world.number)
 		return (hyp_world_bad_id);
 
-	if (HYP_WORLD_STATUS_FLAGS(hyp.table[id].status)
-					== HYP_WORLD_STATUS_FLAG_UNDELETABLE) {
+	if (hyp.world.table[id].status.LOCKED == 1)
 		return (hyp_world_undeletable);
-	}
 
-	hyp.table[id].status = HYP_WORLD_STATUS_STATE_UNUSED;
+	hyp.world.table[id].status.USED = 0;
 }
diff --git a/src/modules/keyboard/keyboard.c b/src/modules/keyboard/keyboard.c
index 85f5aea..02bac79 100644
--- a/src/modules/keyboard/keyboard.c
+++ b/src/modules/keyboard/keyboard.c
@@ -1,5 +1,5 @@
-#include "vhex/keyboard.h"
-#include "vhex/module.h"
+#include <vhex/keyboard.h>
+#include <vhex/module.h>
 
 /* module init */
 
@@ -23,4 +23,4 @@ struct vhex_module mod_keyboard = {
 	.init = &__keyboard_init,
 	.quit = &__keyboard_quit,
 };
-VHEX_DECLARE_MODULE(03, mod_keyboard);
+VHEX_DECLARE_MODULE(04, mod_keyboard);
diff --git a/src/modules/keyboard/keycache.c b/src/modules/keyboard/keycache.c
index 665dfa1..550ae07 100644
--- a/src/modules/keyboard/keycache.c
+++ b/src/modules/keyboard/keycache.c
@@ -1,5 +1,5 @@
 #include <vhex/keyboard.h>
-#include <vhex/drivers/cpu.h>
+#include <vhex/driver/cpu.h>
 
 /* Internal cache, used like chained list.
    @note:
diff --git a/vxsdk.toml b/vxsdk.toml
index 7f1c03c..049dd3c 100644
--- a/vxsdk.toml
+++ b/vxsdk.toml
@@ -1,9 +1,13 @@
-[package]
+[project]
 name = 'vxkernel'
 version = '0.5.0'
 
 [build]
-configure = 'mkdir -p build && cd build && ../config --board=fxcg50 --format=static --verbose'
+configure = 'mkdir -p build && cd build && ../configure --board=fxcg50'
 build     = 'cd build && make'
 install   = 'cd build && make install'
 uninstall = 'cd build && make uninstall'
+
+[dependencies]
+sh-elf-vhex = 'master'
+