diff --git a/board/fxcg50/fxcg50.ld b/board/fxcg50/fxcg50.ld
index 682f57a..5c768e4 100644
--- a/board/fxcg50/fxcg50.ld
+++ b/board/fxcg50/fxcg50.ld
@@ -13,6 +13,8 @@ MEMORY
 {
 	/* virtual memory, read-write segment */
 	userram (WX) : o = 0x00000000, l = 1M
+	/* On-chip IL memory */
+	ilram (rwx):  o = 0xe5200000, l = 4k
 }
 
 SECTIONS
@@ -153,6 +155,21 @@ SECTIONS
 
 	} > userram
 
+	/* On-chip memory sections: IL and Y (X is reserved) */
+
+	. = ORIGIN(ilram);
+	.ilram ALIGN(4) : ALIGN(4) {
+		_lilram = LOADADDR(.ilram);
+		_rilram = . ;
+
+		*(.vhex.ilram)
+
+		. = ALIGN(16);
+	} > ilram AT> userram
+	_silram = SIZEOF(.ilram);
+
+
+
 	/* unwanted section */
 	/DISCARD/ : {
 		*(.rela.debug*)
diff --git a/board/fxcg50/initialize.c b/board/fxcg50/initialize.c
index 473535e..dcb6e1c 100644
--- a/board/fxcg50/initialize.c
+++ b/board/fxcg50/initialize.c
@@ -16,6 +16,9 @@
 extern void (*bctors)(void), (*ectors)(void);
 extern void (*bdtors)(void), (*edtors)(void);
 
+/* on-chip RAM information */
+extern uint32_t lilram, silram, rilram;		/* IL memory section */
+
 /* User-provided main() function */
 extern int main(void);
 
@@ -30,6 +33,22 @@ static void callarray(void (**f)(void), void (**l)(void))
 	while(f < l) (*(*f++))();
 }
 
+/* regcpy(): Copy a memory region using symbol information
+   @l  Source pointer (load address)
+   @s  Size of area (should be a multiple of 16)
+   @r  Destination pointer (relocation address) */
+static void regcpy(uint32_t * __restrict l, int32_t s, uint32_t * __restrict r)
+{
+	while(s > 0)
+	{
+		*r++ = *l++;
+		*r++ = *l++;
+		*r++ = *l++;
+		*r++ = *l++;
+		s -= 16;
+	}
+}
+
 /* initialize() : Where it all starts
 
     We are currently in a RAM location at a non-constant address due to the
@@ -93,6 +112,10 @@ void initialize(void)
 	   tell us if we are running in an emulator or on a real device. */
 	hw_detect();
 
+	/* move special on-chip RAM section */
+	regcpy(&lilram, (uintptr_t)&silram, &rilram);
+
+
 	/* Install Vhex, switch VBR, initialize drivers and modules */
 	kinit();
 
diff --git a/include/vhex/display.h b/include/vhex/display.h
index 7fddbd9..c6d8352 100644
--- a/include/vhex/display.h
+++ b/include/vhex/display.h
@@ -43,6 +43,6 @@ VINLINE size_t dheight(void)
 //---
 
 /* dclear_render() : internal pipeline drawing */
-extern void dclear_render(struct dshader_surface *surface, uint32_t color);
+extern void dclear_render(dsurface_t *surface, uint32_t color);
 
 #endif /*__VHEX_DISPLAY__*/
diff --git a/include/vhex/display/color.h b/include/vhex/display/color.h
index 9fcc2fc..a5ba021 100644
--- a/include/vhex/display/color.h
+++ b/include/vhex/display/color.h
@@ -4,16 +4,16 @@
 
 //FIXME: this is plateform-specific :/
 enum {
-	C_WHITE = 0xffff,
-	C_LIGHT = 0xad55,
-	C_DARK  = 0x528a,
-	C_BLACK = 0x0000,
+	C_WHITE  = 0xffff,
+	C_LIGHT  = 0xad55,
+	C_DARK   = 0x528a,
+	C_BLACK  = 0x0000,
 
-	C_RED   = 0xf800,
-	C_GREEN = 0x07e0,
-	C_BLUE  = 0x001f,
+	C_RED    = 0xf800,
+	C_GREEN  = 0x07e0,
+	C_BLUE   = 0x001f,
 
-	C_NONE = -1,
+	C_NONE   = -1,
 	C_INVERT = -2,
 };
 
diff --git a/include/vhex/display/font.h b/include/vhex/display/font.h
index 9ba8014..9cec5b6 100644
--- a/include/vhex/display/font.h
+++ b/include/vhex/display/font.h
@@ -1,91 +1,2 @@
-#ifndef __VHEX_DISPLAY_FONT__
-# define __VHEX_DISPLAY_FONT__
-
-#include <vhex/defs/types.h>
-#include <vhex/defs/attributes.h>
-#include <vhex/display/shader.h>
-
-/* font_t: Font data encoded for dfont*() functions */
-typedef struct font {
-	/* Font name (NUL-terminated), NULL if no title */
-	char const *name;
-
-	/* Font shape flags */
-	byte_union(shape,
-		uint8_t bold	:1;
-		uint8_t italic	:1;
-		uint8_t serif	:1;
-		uint8_t mono	:1;
-		uint8_t 	:3;
-		uint8_t prop	:1;
-	);
-
-	/* Character spacing (usually 1) */
-	uint8_t char_spacing;
-
-	/* glyph information */
-	struct {
-		uint8_t height;
-		uint8_t line_height;
-		uint32_t *data;
-		uint32_t count;
-
-		union {
-			/* For monospaced fonts */
-			struct {
-				uint8_t width;
-				uint16_t storage_size;
-			} mono;
-			/* For proportional fonts */
-			struct __workaround {
-				uint8_t width;
-				uint16_t index;
-				uint8_t shift;
-			} *prop;
-		};
-	} glyph;
-
-	/* unicode blocks */
-	struct {
-		struct {
-			/* Unicode point of first character in block */
-			uint32_t start   :20;
-			/* Length of block */
-			uint32_t length  :12;
-		} *blocks;
-		uint8_t block_count;
-	} unicode;
-
-} VPACKED(4) font_t;
-
-/* dfont_get() : get the current font */
-extern font_t *dfont_get(void);
-
-/* dfont_text_geometry() : get the char geometry */
-extern int dfont_text_geometry(
-	font_t *font,
-	char const * const str_char,
-	int *size,
-	size_t *w,
-	size_t *h
-);
-
-
-//---
-// Kernel-level API
-//---
-
-/* dfont_char_render() : character render */
-extern void dfont_char_render(
-	struct dshader_surface *surface,
-	int glyph_idx,
-	uint32_t *arg
-);
-
-/* dfont_glyph_index(): Obtain the glyph index of a Unicode code point */
-extern int dfont_glyph_index(font_t const *f, uint32_t code_point);
-
-/* dfont_render() : draw caracter in surface */
-extern void dfont_text_render(struct dshader_surface *surface, uint32_t *arg);
-
-#endif /* __VHEX_DISPLAY_FONT__ */
+#include <vhex/display/font/information.h>
+#include <vhex/display/font/render.h>
diff --git a/include/vhex/display/font/information.h b/include/vhex/display/font/information.h
new file mode 100644
index 0000000..40bb0a6
--- /dev/null
+++ b/include/vhex/display/font/information.h
@@ -0,0 +1,24 @@
+#ifndef __VHEX_DISPLAY_FONT_INFORMATION__
+# define __VHEX_DISPLAY_FONT_INFORMATION__
+
+#include <vhex/display/font/types.h>
+
+/* dfont_get() : get the current font */
+extern font_t *dfont_get(void);
+
+/* dfont_glyph_index(): Obtain the glyph index of a Unicode code point */
+extern int dfont_glyph_index(font_t const *f, uint32_t code_point);
+
+/* dfont_utf8_next(): Read the next UTF-8 code point of a string */
+extern uint32_t dfont_utf8_next(uint8_t const **str_pointer);
+
+/* dfont_text_geometry() : get the rendered text geometry with a given font */
+extern int dfont_text_geometry(
+	font_t *font,
+	char const * const str_char,
+	int *size,
+	size_t *w,
+	size_t *h
+);
+
+#endif /* __VHEX_DISPLAY_FONT_INFORMATION__ */
diff --git a/include/vhex/display/font/render.h b/include/vhex/display/font/render.h
new file mode 100644
index 0000000..fe5851a
--- /dev/null
+++ b/include/vhex/display/font/render.h
@@ -0,0 +1,23 @@
+#ifndef __VHEX_DISPLAY_FONT_RENDER__
+# define __VHEX_DISPLAY_FONT_RENDER__
+
+#include <vhex/display/types.h>
+
+//---
+// User-level API
+//---
+
+/* dfont_cjar() : display one char */
+extern void dfont_char(uint32_t n, int x, int y, int fg, int bg);
+
+//---
+// kernel-level API
+//---
+
+extern void dfont_char_render(
+	dsurface_t *surface,
+	int glyph_idx,
+	uint32_t *arg
+);
+
+#endif /* __VHEX_DISPLAY_FONT_RENDER__ */
diff --git a/include/vhex/display/font/types.h b/include/vhex/display/font/types.h
new file mode 100644
index 0000000..314cc3c
--- /dev/null
+++ b/include/vhex/display/font/types.h
@@ -0,0 +1,60 @@
+#ifndef __VHEX_DISPLAY_FONT_TYPES__
+# define __VHEX_DISPLAY_FONT_TYPES__
+
+#include <vhex/defs/types.h>
+#include <vhex/defs/attributes.h>
+
+/* font_t: Font data encoded for dfont*() functions */
+typedef struct font {
+	/* Font name (NUL-terminated), NULL if no title */
+	char const *name;
+
+	/* Font shape flags */
+	byte_union(shape,
+		uint8_t bold	:1;
+		uint8_t italic	:1;
+		uint8_t serif	:1;
+		uint8_t mono	:1;
+		uint8_t 	:3;
+		uint8_t prop	:1;
+	);
+
+	/* Character spacing (usually 1) */
+	uint8_t char_spacing;
+
+	/* glyph information */
+	struct {
+		uint8_t height;
+		uint8_t line_height;
+		uint32_t *data;
+		uint32_t count;
+
+		union {
+			/* For monospaced fonts */
+			struct {
+				uint8_t width;
+				uint16_t storage_size;
+			} mono;
+			/* For proportional fonts */
+			struct __workaround {
+				uint8_t width;
+				uint16_t index;
+				uint8_t shift;
+			} *prop;
+		};
+	} glyph;
+
+	/* unicode blocks */
+	struct {
+		struct {
+			/* Unicode point of first character in block */
+			uint32_t start   :20;
+			/* Length of block */
+			uint32_t length  :12;
+		} *blocks;
+		uint8_t block_count;
+	} unicode;
+
+} VPACKED(4) font_t;
+
+#endif /* __VHEX_DISPLAY_FONT_TYPES__ */
diff --git a/include/vhex/display/interface.h b/include/vhex/display/interface.h
new file mode 100644
index 0000000..bf029f9
--- /dev/null
+++ b/include/vhex/display/interface.h
@@ -0,0 +1,16 @@
+#ifndef __VHEX_DISPLAY_INTERFACE__
+# define __VHEX_DISPLAY_INTERFACE__
+
+#include <vhex/display/types.h>
+
+/* dstack_drv_interface - driver interface */
+struct dstack_drv_interface {
+	int (*frame_start)(dsurface_t *);
+	int (*frame_frag_next)(dsurface_t *);
+	int (*frame_frag_send)(dsurface_t *);
+	int (*frame_end)(dsurface_t *);
+	size_t display_width;
+	size_t display_height;
+};
+
+#endif /* __VHEX_DISPLAY_INTERFACE__ */
diff --git a/include/vhex/display/shader.h b/include/vhex/display/shader.h
index fb7462e..612fb03 100644
--- a/include/vhex/display/shader.h
+++ b/include/vhex/display/shader.h
@@ -1,33 +1,18 @@
 #ifndef __VHEX_DISPLAY_SHADER__
 # define __VHEX_DISPLAY_SHADER__
 
-#include <vhex/defs/attributes.h>
-#include <vhex/defs/types.h>
-
-/* dshader_surface - Describe the surface */
-struct dshader_surface {
-	void *draw;
-	void *frag;
-	size_t width;
-	size_t height;
-	int x1;
-	int y1;
-	int x2;
-	int y2;
-};
-typedef struct dshader_surface dsurface_t;
+#include <vhex/display/types.h>
 
 /* dshader - display shader definition */
 struct dshader_call {
 	int (*routine)(
-		struct dshader_surface *surface,
+		dsurface_t *surface,
 		uint32_t *draw_args,
 		uint32_t *shader_args
 	);
 	uint32_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 }
diff --git a/include/vhex/display/stack.h b/include/vhex/display/stack.h
index fce9cc6..9f979e8 100644
--- a/include/vhex/display/stack.h
+++ b/include/vhex/display/stack.h
@@ -4,12 +4,10 @@
 #include <vhex/display/shader.h>
 #include <vhex/display/types.h>
 
+
 /* dstack_call - dstack indirect call (same as dshader) */
 struct dstack_call {
-	void (*routine)(
-		struct dshader_surface *surface,
-		uint32_t *draw_args
-	);
+	void (*routine)(dsurface_t *surface, uint32_t *draw_args);
 	uint32_t args[12];
 };
 typedef struct dstack_call dstack_call_t;
@@ -32,41 +30,12 @@ struct dstack_action {
 }
 
 
-/* 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 *);
-	size_t display_width;
-	size_t display_height;
-};
-
 //---
 // Display stack API
 //---
 
 /* dstack_init() : Initialise the draw stack (should not be involved) */
-extern int dstack_init(struct dstack_config *config);
+extern int dstack_init(void);
 
 /* dstack_add_action() : add a new action in the draw stack */
 extern did_t dstack_add_action(
diff --git a/include/vhex/display/text.h b/include/vhex/display/text.h
index e03be0a..372818d 100644
--- a/include/vhex/display/text.h
+++ b/include/vhex/display/text.h
@@ -1,46 +1,2 @@
-#ifndef __VHEX_DISPLAY_TEXT__
-# define __VHEX_DISPLAY_TEXT__
-
-#include <vhex/defs/types.h>
-#include <vhex/display/types.h>
-
-/* 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. */
-enum {
-	/* Horizontal settings: default in dtext() is DTEXT_LEFT */
-	DTEXT_LEFT   = 0,
-	DTEXT_CENTER = 1,
-	DTEXT_RIGHT  = 2,
-	/* Vertical settings: default in dtext() is DTEXT_TOP */
-	DTEXT_TOP    = 0,
-	DTEXT_MIDDLE = 1,
-	DTEXT_BOTTOM = 2,
-};
-
-/* dtext_opt(): Display a string of text */
-extern did_t dtext_opt(
-	int x, int y,
-	int fg, int bg,
-	int halign, int valign,
-	char const * const str, int size
-);
-
-/* dtext() : display raw text */
-extern did_t dtext(int x, int y, int fg, char const * const text);
-
-/* dprint_opt(): Display a formated string */
-extern did_t dprint_opt(
-	int x, int y,
-	int fg, int bg,
-	int halign, int valign,
-	char const * const str, ...
-);
-
-/* dprint() : display formated text */
-extern did_t dprint(int x, int y, int fg, char const * const text, ...);
-
-/* dnsize(): Get the width and height of rendered text for the n first char */
-extern int dtext_geometry(char const * const str, int *n, size_t *w, size_t *h);
-
-#endif /* __VHEX_DISPLAY_TEXT__ */
+#include <vhex/display/text/information.h>
+#include <vhex/display/text/render.h>
diff --git a/include/vhex/display/text/information.h b/include/vhex/display/text/information.h
new file mode 100644
index 0000000..8b99600
--- /dev/null
+++ b/include/vhex/display/text/information.h
@@ -0,0 +1,9 @@
+#ifndef __VHEX_DISPLAY_TEXT_INFORMATION__
+# define __VHEX_DISPLAY_TEXT_INFORMATION__
+
+#include <vhex/defs/types.h>
+
+/* dtext_geometry() : get the rendered text geometry with the current font */
+extern int dtext_geometry(char const * const str, int *n, size_t *w, size_t *h);
+
+#endif /* __VHEX_DISPLAY_TEXT_INFORMATION__ */
diff --git a/include/vhex/display/text/render.h b/include/vhex/display/text/render.h
new file mode 100644
index 0000000..255c2fe
--- /dev/null
+++ b/include/vhex/display/text/render.h
@@ -0,0 +1,43 @@
+#ifndef __VHEX_DISPLAY_TEXT_RENDER__
+# define __VHEX_DISPLAY_TEXT_RENDER__
+
+#include <vhex/defs/types.h>
+#include <vhex/display/types.h>
+
+/* 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. */
+enum {
+	/* Horizontal settings: default in dtext() is DTEXT_LEFT */
+	DTEXT_LEFT   = 0,
+	DTEXT_CENTER = 1,
+	DTEXT_RIGHT  = 2,
+	/* Vertical settings: default in dtext() is DTEXT_TOP */
+	DTEXT_TOP    = 0,
+	DTEXT_MIDDLE = 1,
+	DTEXT_BOTTOM = 2,
+};
+
+/* dtext_opt(): Display a string of text */
+extern did_t dtext_opt(
+	int x, int y,
+	int fg, int bg,
+	int halign, int valign,
+	char const * const str, int size
+);
+
+/* dtext() : display raw text */
+extern did_t dtext(int x, int y, int fg, char const * const text);
+
+/* dprint_opt(): Display a formated string */
+extern did_t dprint_opt(
+	int x, int y,
+	int fg, int bg,
+	int halign, int valign,
+	char const * const str, ...
+);
+
+/* dprint() : display formated text */
+extern did_t dprint(int x, int y, int fg, char const * const text, ...);
+
+#endif /* __VHEX_DISPLAY_TEXT_RENDER__ */
diff --git a/include/vhex/display/types.h b/include/vhex/display/types.h
index ef15607..43ab185 100644
--- a/include/vhex/display/types.h
+++ b/include/vhex/display/types.h
@@ -1,7 +1,21 @@
 #ifndef __VHEX_DISPLAY_TYPES__
 # define __VHEX_DISPLAY_TYPES__
 
+#include <vhex/defs/types.h>
+
 /* draw ID */
 typedef int did_t;
 
+/* dsurface - Describe the surface */
+struct dsurface {
+	void *vram;
+	size_t width;
+	size_t height;
+	int x1;
+	int y1;
+	int x2;
+	int y2;
+};
+typedef struct dsurface dsurface_t;
+
 #endif /* __VHEX_DISPLAY_TYPES__ */
diff --git a/make/Makefile b/make/Makefile
index 9e172f8..edd4472 100644
--- a/make/Makefile
+++ b/make/Makefile
@@ -156,6 +156,7 @@ t-$1-$2-gcc	:= $$(CONFIG.$1.TOOLCHAIN.PREFIX)gcc
 t-$1-$2-ldflags	:= $$(CONFIG.$1.TOOLCHAIN.LDFLAGS)
 t-$1-$2-cflags	:= $$(CONFIG.$1.TOOLCHAIN.CFLAGS)
 t-$1-$2-cflags	+= -fpic -ffreestanding -nostdlib -fstrict-volatile-bitfields -O1
+t-$1-$2-cflags	+= -Wa,--dsp
 
 # generate compiler information (used to find some library like libgcc.a)
 t-$1-$2-gcc-base	:= $$(shell $$(CONFIG.$1.TOOLCHAIN.PREFIX)gcc --print-search-dirs | grep install | sed 's/install: //')
diff --git a/src/drivers/screen/R61524/frame.S b/src/drivers/screen/R61524/frame.S
index 796d441..eeb7e91 100644
--- a/src/drivers/screen/R61524/frame.S
+++ b/src/drivers/screen/R61524/frame.S
@@ -3,11 +3,42 @@
 
 .global	_r61524_frame_frag_send
 
-.align 4
+.balign 4
 
 ! r61524_frame_frag_send() : send fragment in screen
 _r61524_frame_frag_send:
 
+	! prepare loop information
+	mov	#0xb4, r3		! EX (1)
+	mov.l	@(8, r4), r0		! LS
+	shll8	r3			! EX (2)
+	mov.l	@(0, r4), r2		! LS
+	shll16	r3			! EX (3)
+	mov.w	long_frag, r1		! LS
+	cmp/eq	#4, r0			! EX (4)
+	bf	1f			! BR (?)
+	mov.w	short_frag, r1		! LS
+	nop				! MT
+
+	! prepare loop
+1:	ldrs	2f
+	ldre	3f
+	nop
+	ldrc	r1
+
+2:	mov.w	@r2+, r0
+3:	mov.w	r0, @r3
+
+	rts
+	nop
+
+long_frag:
+	.word	3960
+short_frag:
+	.word	1584
+#endif
+
+#if 0
 	! check number of word to be send
 	mov.l	@(20, r4), r0		! LS
 	cmp/eq	#220, r0		! EX (1)
diff --git a/src/drivers/screen/R61524/r61524.c b/src/drivers/screen/R61524/r61524.c
index f7703eb..7d07e92 100644
--- a/src/drivers/screen/R61524/r61524.c
+++ b/src/drivers/screen/R61524/r61524.c
@@ -1,25 +1,14 @@
 #include <vhex/defs/types.h>
 #include <vhex/driver.h>
 #include <vhex/driver/screen/r61524.h>
-#include <vhex/display/stack.h>
+#include <vhex/display/interface.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)
-{
-	uint32_t *xram = surface->draw;
-	int size = (surface->y1 == 220) ? 792 : 1980;
-
-	for (int i = 0; i < size; ++i) {
-		xram[i] = 0x00010001;
-	}
-}
-
 /* r61524_frame_start() - prepar the screen and reset surfaces */
-int r61524_frame_start(struct dshader_surface *surface)
+int r61524_frame_start(dsurface_t *surface)
 {
 	/* Set the windows size */
 	r61524_select(horizontal_ram_start);
@@ -41,21 +30,17 @@ int r61524_frame_start(struct dshader_surface *surface)
 	r61524_select(write_data);
 
 	/* initialize surface information */
-	surface->draw = (void*)0xe5007000;
-	surface->frag = (void*)0xe5017000;
+	surface->vram = (void*)0xe5017000;
 	surface->width = 396;
 	surface->height = 10;
 	surface->x1 = 0;
 	surface->y1 = 0;
 	surface->x2 = 395;
 	surface->y2 = 9;
-
-	/* reset the two surfaces */
-	r61524_clear_surface(surface);
 	return (0);
 }
 
-int r61524_frame_frag_next(struct dshader_surface *surface)
+int r61524_frame_frag_next(dsurface_t *surface)
 {
 	surface->y1 += 10;
 	if (surface->y1 >= 224) {
@@ -69,9 +54,9 @@ int r61524_frame_frag_next(struct dshader_surface *surface)
 	return (0);
 }
 
-VWEAK int r61524_frame_frag_send(struct dshader_surface *surface)
+VWEAK int r61524_frame_frag_send(dsurface_t *surface)
 {
-	uint16_t * restrict yram = surface->frag;
+	uint16_t * restrict yram = surface->vram;
 	int size = (surface->y1 == 220) ? 1584 : 3960;
 
 	for (int i = 0; i < size; ++i) {
@@ -80,7 +65,7 @@ VWEAK int r61524_frame_frag_send(struct dshader_surface *surface)
 	return (0);
 }
 
-int r61524_frame_end(struct dshader_surface *surface)
+int r61524_frame_end(dsurface_t *surface)
 {
 	(void)surface;
 	return (0);
diff --git a/src/modules/display/dclear.c b/src/modules/display/dclear.c
index 9fe1441..1c5bc87 100644
--- a/src/modules/display/dclear.c
+++ b/src/modules/display/dclear.c
@@ -7,12 +7,12 @@
 //---
 
 /* dclear_draw() : real drawing algorithm */
-void dclear_render(struct dshader_surface *surface, uint32_t color)
+void dclear_render(dsurface_t *surface, uint32_t color)
 {
 	uint32_t *vram;
 	int size = (surface->y1 == 220) ? 792 : 1980;
 
-	vram = surface->frag;
+	vram = surface->vram;
 	for (int i = 0; i < size; ++i)
 		vram[i] = color;
 }
@@ -22,7 +22,7 @@ void dclear_render(struct dshader_surface *surface, uint32_t color)
 //---
 
 /* dclear_dstack() : dstack rwrapper primitive */
-void dclear_dstack(struct dshader_surface *surface, uint32_t *arg)
+void dclear_dstack(dsurface_t *surface, uint32_t *arg)
 {
 	dclear_render(surface, arg[0]);
 }
diff --git a/src/modules/display/display.c b/src/modules/display/display.c
index fc94a84..b1ad116 100644
--- a/src/modules/display/display.c
+++ b/src/modules/display/display.c
@@ -6,12 +6,7 @@
 /* __display_init() : initialize the display */
 static void __display_init(void)
 {
-	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);
+	dstack_init();
 }
 
 /* __display_quit() : uninit the display */
diff --git a/src/modules/display/draw/dline.c b/src/modules/display/draw/dline.c
index 836c6b2..950e3b3 100644
--- a/src/modules/display/draw/dline.c
+++ b/src/modules/display/draw/dline.c
@@ -76,7 +76,7 @@ void dhline_render(dsurface_t *surface, int y, int x1, int x2, int color)
 
 	/* Use longwords to do the copy, but first paint the endpoints to heed
 	   for odd x1 and x2. Checking the parity may be a waste of time. */
-	uint16_t *vram = surface->frag;
+	uint16_t *vram = surface->vram;
 	if (color != C_INVERT) {
 		vram[offset + x1] = color;
 		vram[offset + x2] = color;
@@ -117,7 +117,7 @@ void dvline_render(dsurface_t *surface, int x, int y1, int y2, int color)
 	y1 -= surface->y1;
 	y2 -= surface->y1;
 
-	uint16_t *vram = surface->frag;
+	uint16_t *vram = surface->vram;
 	uint16_t *v = &vram[(surface->width * y1) + x];
 	int height = y2 - y1;
 
diff --git a/src/modules/display/draw/dpixel.c b/src/modules/display/draw/dpixel.c
index 1a1bbe9..4cc3076 100644
--- a/src/modules/display/draw/dpixel.c
+++ b/src/modules/display/draw/dpixel.c
@@ -26,17 +26,20 @@ void dpixel_render(dsurface_t *surface, int x, int y, int color)
 	int draw_idx = real_y + real_x;
 
 	/* handle special color */
-	//uint16_t *draw = surface->draw;
-	uint16_t *frag = surface->frag;
+	uint16_t *vram = surface->vram;
 	if (color == C_INVERT)
-		color = frag[draw_idx] ^ 0xffff;
+		color = vram[draw_idx] ^ 0xffff;
 
 	/* set the pixel */
-	frag[draw_idx] = color;
+	vram[draw_idx] = color;
 }
 
+//---
+// Dstack-level API
+//---
+
 /* dpixel_render_dstack() : dstack-API compatible render */
-void dpixel_dstack(struct dshader_surface *surface, uint32_t *arg)
+void dpixel_dstack(dsurface_t *surface, uint32_t *arg)
 {
 	dpixel_render(surface, arg[0], arg[1], arg[2]);
 }
diff --git a/src/modules/display/dstack.c b/src/modules/display/dstack.c
index 699b22d..adc1401 100644
--- a/src/modules/display/dstack.c
+++ b/src/modules/display/dstack.c
@@ -1,5 +1,6 @@
 #include <vhex/display/stack.h>
 #include <vhex/display/shader.h>
+#include <vhex/display/interface.h>
 #include <vhex/driver.h>
 
 #include <stdlib.h>
@@ -33,21 +34,21 @@ static struct {
 //---
 
 /* dstack_init() : Initialise the draw stack (should not be involved) */
-int dstack_init(struct dstack_config *config)
+int dstack_init(void)
 {
 	dstack_info.pool.action = calloc(
-		config->default_icall_pool_slot,
+		16,
 		sizeof(struct dstack_action)
 	);
 	dstack_info.pool.idx = -1;
-	dstack_info.pool.slots = config->default_icall_pool_slot;
+	dstack_info.pool.slots = 16;
+
 	for (int i = 0; i < dstack_info.pool.slots; ++i) {
 		dstack_info.pool.action[i].shader.table = calloc(
-			config->default_shader_per_action,
+			4,
 			sizeof(*dstack_info.pool.action[i].shader.table)
 		);
-		dstack_info.pool.action[i].shader.number =
-					config->default_shader_per_action;
+		dstack_info.pool.action[i].shader.number = 4;
 		dstack_info.pool.action[i].shader.idx = -1;
 	}
 
@@ -138,7 +139,7 @@ did_t dstack_add_action(
 /* dstack_render(): render a frame */
 void dstack_render(void)
 {
-	struct dshader_surface surface;
+	dsurface_t surface;
 	struct dstack_action *action;
 
 	action = dstack_info.pool.action;
diff --git a/src/modules/display/text/dfont.c b/src/modules/display/font/information.c
similarity index 52%
rename from src/modules/display/text/dfont.c
rename to src/modules/display/font/information.c
index 13c7490..f3900a7 100644
--- a/src/modules/display/text/dfont.c
+++ b/src/modules/display/font/information.c
@@ -1,13 +1,7 @@
 #include <vhex/display/font.h>
-#include <vhex/display/draw/pixel.h>
-#include <vhex/display/color.h>
-
-//---
-// Internal
-//---
 
 /* dfont_utf8_next(): Read the next UTF-8 code point of a string */
-static uint32_t dfont_utf8_next(uint8_t const **str_pointer)
+uint32_t dfont_utf8_next(uint8_t const **str_pointer)
 {
 	uint8_t const *str = *str_pointer;
 	uint8_t lead = *str++;
@@ -76,128 +70,6 @@ int dfont_glyph_index(font_t const *f, uint32_t code_point)
 	return code_point;
 }
 
-/* dfont_char_render() : */
-void dfont_char_render(
-	struct dshader_surface *surface,
-	int glyph_idx,
-	uint32_t *arg
-) {
-	uint32_t glyph_bitmap;
-	uint32_t glyph_shift;
-	int glyph_width;
-	int glyph_size;
-	font_t *font;
-	int counter;
-	int sx;
-	int x;
-	int y;
-
-	x = arg[0];
-	y = arg[1];
-
-	/* generate font index / shift information */
-	font = dfont_get();
-	if (font->shape.prop == 1) {
-		glyph_width = font->glyph.prop[glyph_idx].width;
-		glyph_shift = font->glyph.prop[glyph_idx].shift;
-		glyph_idx   = font->glyph.prop[glyph_idx].index;
-		glyph_size  = glyph_width * font->glyph.height;
-	} else {
-		glyph_width = font->glyph.mono.width;
-		glyph_size  = font->glyph.mono.storage_size;
-		glyph_shift = glyph_size * glyph_idx;
-		glyph_idx   = glyph_shift >> 8;
-		glyph_shift = glyph_shift & 0xff;
-	}
-
-	/* drawing algo */
-	//TODO: cache surface data (limit read/write)
-	sx = x;
-	counter = 0;
-	glyph_shift = 0x80000000 >> glyph_shift;
-	glyph_bitmap = font->glyph.data[glyph_idx];
-	for (int i = 0; i < glyph_size; ++i)
-	{
-		if (glyph_bitmap & glyph_shift) {
-			dpixel_render(surface, x, y, arg[4]);
-		} else {
-			dpixel_render(surface, x, y, arg[5]);
-		}
-
-		/* update font bitmap index / shift */
-		glyph_shift >>= 1;
-		if (glyph_shift == 0x00000000) {
-			glyph_shift = 0x80000000;
-			glyph_bitmap = font->glyph.data[++glyph_idx];
-		}
-
-		/* update bitmap position */
-		x += 1;
-		counter += 1;
-		if (counter >= glyph_width) {
-			counter = 0;
-			x = sx;
-			y += 1;
-		}
-	}
-}
-
-//---
-// Kernel-level API
-//---
-
-/* dfont_render() : draw caracter in surface */
-void dfont_text_render(struct dshader_surface *surface, uint32_t *arg)
-{
-	uint32_t code_point;
-	uint8_t const * str;
-	font_t *font;
-	int glyph_idx;
-	int glyph_width;
-	int counter;
-	int sx;
-	int sy;
-
-	/* check culling */
-	if (((int)arg[3] < surface->y1 && (int)arg[1] > surface->y2)
-		|| ((int)arg[2] < surface->x1 && (int)arg[0] > surface->x2)) {
-		return;
-	}
-
-	/* draw algo (update me) */
-	sx = arg[0];
-	sy = arg[1];
-	counter = -1;
-	font = dfont_get();
-	str = (void*)(uintptr_t)arg[6];
-	while (++counter < (int)arg[7])
-	{
-		code_point = dfont_utf8_next(&str);
-		if (code_point == '\n') {
-			arg[1] += font->glyph.height;
-			arg[0] = sx;
-			continue;
-		}
-
-		glyph_idx = dfont_glyph_index(font, code_point);
-		glyph_width = font->glyph.mono.width;
-		if (font->shape.prop == 1)
-			glyph_width = font->glyph.prop[glyph_idx].width;
-
-		dfont_char_render(surface, glyph_idx, arg);
-
-		arg[0] += glyph_width + font->char_spacing;
-
-	}
-	arg[1] = sy;
-	arg[0] = sx;
-}
-
-//---
-// Public API
-//---
-
-
 /* dfont_get() : get the current font */
 font_t *dfont_get(void)
 {
@@ -205,7 +77,7 @@ font_t *dfont_get(void)
 	return &font8x9;
 }
 
-/* dfont_geometry() : get the char geometry */
+/* dfont_text_geometry() : get the rendered text geometry with a given font */
 int dfont_text_geometry(
 	font_t *font,
 	char const * const str_char,
diff --git a/src/modules/display/font/render.c b/src/modules/display/font/render.c
new file mode 100644
index 0000000..52b76b1
--- /dev/null
+++ b/src/modules/display/font/render.c
@@ -0,0 +1,108 @@
+#include <vhex/display/font.h>
+#include <vhex/display/draw/pixel.h>
+#include <vhex/display/color.h>
+#include <vhex/display/stack.h>
+
+//---
+// Kernel-level render API
+//---
+
+/* dfont_char_render() : */
+void dfont_char_render(
+	dsurface_t *surface,
+	int glyph_idx,
+	uint32_t *arg
+) {
+	uint32_t glyph_bitmap;
+	uint32_t glyph_shift;
+	int glyph_width;
+	int glyph_size;
+	font_t *font;
+	int counter;
+	int sx;
+	int x;
+	int y;
+
+	x = arg[0];
+	y = arg[1];
+
+	/* generate font index / shift information */
+	font = dfont_get();
+	if (font->shape.prop == 1) {
+		glyph_width = font->glyph.prop[glyph_idx].width;
+		glyph_shift = font->glyph.prop[glyph_idx].shift;
+		glyph_idx   = font->glyph.prop[glyph_idx].index;
+		glyph_size  = glyph_width * font->glyph.height;
+	} else {
+		glyph_width = font->glyph.mono.width;
+		glyph_size  = font->glyph.mono.storage_size;
+		glyph_shift = glyph_size * glyph_idx;
+		glyph_idx   = glyph_shift >> 8;
+		glyph_shift = glyph_shift & 0xff;
+	}
+
+	/* drawing algo */
+	//TODO: cache surface data (limit read/write)
+	sx = x;
+	counter = 0;
+	glyph_shift = 0x80000000 >> glyph_shift;
+	glyph_bitmap = font->glyph.data[glyph_idx];
+	for (int i = 0; i < glyph_size; ++i)
+	{
+		if (glyph_bitmap & glyph_shift) {
+			dpixel_render(surface, x, y, arg[4]);
+		} else {
+			dpixel_render(surface, x, y, arg[5]);
+		}
+
+		/* update font bitmap index / shift */
+		glyph_shift >>= 1;
+		if (glyph_shift == 0x00000000) {
+			glyph_shift = 0x80000000;
+			glyph_bitmap = font->glyph.data[++glyph_idx];
+		}
+
+		/* update bitmap position */
+		x += 1;
+		counter += 1;
+		if (counter >= glyph_width) {
+			counter = 0;
+			x = sx;
+			y += 1;
+		}
+	}
+}
+
+//---
+// Dstack API
+//---
+
+/* dfont_char_dstack() : dstack wrapper */
+void dfont_char_dstack(dsurface_t *surface, uint32_t *arg)
+{
+	font_t *font = dfont_get();
+	uint32_t buff[6] = {
+		arg[1], arg[2], 0, 0, arg[3], arg[4]
+	};
+
+	dfont_char_render(surface, dfont_glyph_index(font, arg[0]), buff);
+}
+
+//---
+// User-level API
+//---
+
+/* dfont_char() : display one char */
+void dfont_char(uint32_t n, int x, int y, int fg, int bg)
+{
+	dstack_add_action(
+		&DSTACK_CALL(
+			&dfont_char_dstack,
+			n,
+			x, y,
+			fg, bg
+		),
+		NULL,
+		NULL
+	);
+}
diff --git a/src/modules/display/image/render.c b/src/modules/display/image/render.c
index 330a1fe..f1d382d 100644
--- a/src/modules/display/image/render.c
+++ b/src/modules/display/image/render.c
@@ -134,7 +134,7 @@ void dsubimage_render(
 		width  = surface->width - vxs;
 	if ((size_t)(vys + height) > surface->height)
 		height = surface->height - vys;
-	vram = surface->frag;
+	vram = surface->vram;
 
 
 	/* prepare box request */
diff --git a/src/modules/display/text/dascii.c b/src/modules/display/text/dascii.c
deleted file mode 100644
index 5e40c47..0000000
--- a/src/modules/display/text/dascii.c
+++ /dev/null
@@ -1,37 +0,0 @@
-#include <vhex/display.h>
-#include <vhex/defs/types.h>
-
-#include <vhex/display/font.h>
-
-//---
-// Kernel-level API
-//---
-
-void dascii_dstack_render(struct dshader_surface *surface, uint32_t *arg)
-{
-	font_t *font = dfont_get();
-	uint32_t buff[6] = {
-		arg[1], arg[2], 0, 0, arg[3], arg[4]
-	};
-
-	dfont_char_render(surface, dfont_glyph_index(font, arg[0]), buff);
-}
-
-//---
-// User-level API
-//---
-
-/* dascii() : display one char */
-void dascii(char n, int x, int y, int fg, int bg)
-{
-	dstack_add_action(
-		&DSTACK_CALL(
-			&dascii_dstack_render,
-			n,
-			x, y,
-			fg, bg
-		),
-		NULL,
-		NULL
-	);
-}
diff --git a/src/modules/display/text/information.c b/src/modules/display/text/information.c
new file mode 100644
index 0000000..98efddb
--- /dev/null
+++ b/src/modules/display/text/information.c
@@ -0,0 +1,8 @@
+#include <vhex/display/types.h>
+#include <vhex/display/font/information.h>
+
+/* dtext_geometry() : get the rendered text geometry with the current font */
+int dtext_geometry(char const * const str_char, int *s, size_t *w, size_t *h)
+{
+	return dfont_text_geometry(NULL, str_char, s, w, h);
+}
diff --git a/src/modules/display/text/dtext.c b/src/modules/display/text/render.c
similarity index 76%
rename from src/modules/display/text/dtext.c
rename to src/modules/display/text/render.c
index 727ac07..de283fc 100644
--- a/src/modules/display/text/dtext.c
+++ b/src/modules/display/text/render.c
@@ -1,9 +1,7 @@
-#include <vhex/defs/types.h>
-#include <vhex/display/text.h>
-#include <vhex/display/shader.h>
+#include <vhex/display/types.h>
 #include <vhex/display/stack.h>
-#include <vhex/display/color.h>
 #include <vhex/display/font.h>
+#include <vhex/display/text.h>
 #include <vhex/display.h>
 
 #include <stdarg.h>
@@ -97,9 +95,59 @@ static char *dtext_info_register(char const * const str)
 }
 
 //---
-// Public API
+// Dstack API
 //---
 
+/* dfont_render() : draw caracter in surface */
+void dtext_dstack(dsurface_t *surface, uint32_t *arg)
+{
+	uint32_t code_point;
+	uint8_t const * str;
+	font_t *font;
+	int glyph_idx;
+	int glyph_width;
+	int counter;
+	int sx;
+	int sy;
+
+	/* check culling */
+	if (((int)arg[3] < surface->y1 && (int)arg[1] > surface->y2)
+		|| ((int)arg[2] < surface->x1 && (int)arg[0] > surface->x2)) {
+		return;
+	}
+
+	/* draw algo (update me) */
+	sx = arg[0];
+	sy = arg[1];
+	counter = -1;
+	font = dfont_get();
+	str = (void*)(uintptr_t)arg[6];
+	while (++counter < (int)arg[7])
+	{
+		code_point = dfont_utf8_next(&str);
+		if (code_point == '\n') {
+			arg[1] += font->glyph.height;
+			arg[0] = sx;
+			continue;
+		}
+
+		glyph_idx = dfont_glyph_index(font, code_point);
+		glyph_width = font->glyph.mono.width;
+		if (font->shape.prop == 1)
+			glyph_width = font->glyph.prop[glyph_idx].width;
+
+		dfont_char_render(surface, glyph_idx, arg);
+
+		arg[0] += glyph_width + font->char_spacing;
+
+	}
+	arg[1] = sy;
+	arg[0] = sx;
+}
+
+//---
+// Public API
+//---
 
 /* dtext_opt(): Display a string of text */
 did_t dtext_opt(
@@ -113,7 +161,7 @@ did_t dtext_opt(
 	void *real_str;
 
 	/* get text geometry and handle obvious culling */
-	if (dfont_text_geometry(NULL, str, &size, &width, &height) != 0)
+	if (dtext_geometry(str, &size, &width, &height) != 0)
 		return (-1);
 	if (x >= (int)dwidth()
 			|| y >= (int)dheight()
@@ -134,7 +182,7 @@ did_t dtext_opt(
 	/* request draw call */
 	return dstack_add_action(
 		&DSTACK_CALL(
-			&dfont_text_render,
+			&dtext_dstack,
 			x, y, x + width, y + height,
 			fg, bg,
 			(uint32_t)(uintptr_t)real_str, size,