From 8b3b2aa20d15cbc2dc1c5503b93deaa7a2597579 Mon Sep 17 00:00:00 2001
From: Robin Chappatte <robin.chappatte@gmail.com>
Date: Fri, 1 May 2026 21:13:55 +0200
Subject: [PATCH] add directional characters display

---
 assets/sprites/{ghost.ppm => ghost_down.ppm} | Bin
 assets/sprites/ghost_left.ppm                | Bin 0 -> 130 bytes
 assets/sprites/ghost_right.ppm               | Bin 0 -> 130 bytes
 assets/sprites/ghost_up.ppm                  | Bin 0 -> 130 bytes
 assets/sprites/robot.ppm                     | Bin 130 -> 0 bytes
 assets/sprites/robot_down.ppm                | Bin 0 -> 130 bytes
 assets/sprites/robot_left.ppm                | Bin 0 -> 130 bytes
 assets/sprites/robot_right.ppm               | Bin 0 -> 130 bytes
 assets/sprites/robot_up.ppm                  | Bin 0 -> 130 bytes
 build.ts                                     |  10 +-
 src/consts/game.asm                          |  15 --
 src/consts/sprites.asm                       |  19 +-
 src/lib/drawing.asm                          |  53 +++++
 src/lib/u64.asm                              |  18 ++
 src/main.asm                                 |  36 ++-
 src/reserved_space.asm                       |  17 +-
 src/sections/characters_movement.asm         | 231 -------------------
 src/sections/init_ghost_state.asm            |   2 +-
 src/sections/init_robot_state.asm            |   2 +-
 src/sections/init_sprite_lookup_table.asm    |  51 +++-
 src/sections/init_timers.asm                 |  48 ++--
 src/sections/timer_ghost.asm                 |  99 ++++++++
 src/sections/timer_robot.asm                 |  99 ++++++++
 23 files changed, 417 insertions(+), 283 deletions(-)
 rename assets/sprites/{ghost.ppm => ghost_down.ppm} (100%)
 create mode 100644 assets/sprites/ghost_left.ppm
 create mode 100644 assets/sprites/ghost_right.ppm
 create mode 100644 assets/sprites/ghost_up.ppm
 delete mode 100644 assets/sprites/robot.ppm
 create mode 100644 assets/sprites/robot_down.ppm
 create mode 100644 assets/sprites/robot_left.ppm
 create mode 100644 assets/sprites/robot_right.ppm
 create mode 100644 assets/sprites/robot_up.ppm
 create mode 100644 src/lib/u64.asm
 delete mode 100644 src/sections/characters_movement.asm
 create mode 100644 src/sections/timer_ghost.asm
 create mode 100644 src/sections/timer_robot.asm

diff --git a/assets/sprites/ghost.ppm b/assets/sprites/ghost_down.ppm
similarity index 100%
rename from assets/sprites/ghost.ppm
rename to assets/sprites/ghost_down.ppm
diff --git a/assets/sprites/ghost_left.ppm b/assets/sprites/ghost_left.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..5e632614cd9c85d77e087c15d2bb69ea721745f2
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
g<uWog<zir9_zy$KY=|IG2FQSraAn90h!zM50A#u(B>(^b

literal 0
HcmV?d00001

diff --git a/assets/sprites/ghost_right.ppm b/assets/sprites/ghost_right.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..e72da9a532525cc33051f2288550b98766dc984c
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
i<uWog<zir9_zy$KY`7qh0hEW6$l_o@kamy?1_l6Rx+En4

literal 0
HcmV?d00001

diff --git a/assets/sprites/ghost_up.ppm b/assets/sprites/ghost_up.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..c0f2bf7647ed1fbf2fefdbf7c9a50b128628e56b
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
Z<uWog<zir9_zy$KY`7qP21E;l1ORBZBqaa<

literal 0
HcmV?d00001

diff --git a/assets/sprites/robot.ppm b/assets/sprites/robot.ppm
deleted file mode 100644
index 3060135fafb35287ae7fca038046154b548d34bc..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
k<uWog<zir9D2D+c8wCD?M1Uj^z+|8_vIs~TtN=~|0ElBGz5oCK

diff --git a/assets/sprites/robot_down.ppm b/assets/sprites/robot_down.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..20b694aa17854e0c0afd52238100175ed6aa2bcf
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
k<uWog<zir9D2D+c8wCD?M1UliiI4>gAh;lDkXi%@0B5%&CIA2c

literal 0
HcmV?d00001

diff --git a/assets/sprites/robot_left.ppm b/assets/sprites/robot_left.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..68b44fae03b22f734cb569d9c3437f98f14a2016
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
l<uWog<zir9D2D+c8wCDCMIbz&<bSXlI2WQE!UZdbG65FVASnO<

literal 0
HcmV?d00001

diff --git a/assets/sprites/robot_right.ppm b/assets/sprites/robot_right.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..9470f986e7a3925f03845f02d2a62c9a562c3f13
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
m<uWog<zir9D2D+c8_s3;58;7iflMF?;ltEIxj;dfLIwaCIUp$j

literal 0
HcmV?d00001

diff --git a/assets/sprites/robot_up.ppm b/assets/sprites/robot_up.ppm
new file mode 100644
index 0000000000000000000000000000000000000000..dc649d156381dcf279c58b269532bf767ce25db2
GIT binary patch
literal 130
zcmWGA<5E^|E=o--Nlj5ms#I|I^bJrbOD!tS%+FIW)-%#GQ3&w!RVc_QP1nuL<1$q+
f<uWog<zir9D2D+c8;$!PNfyXPlLc}if)Ek_k@F++

literal 0
HcmV?d00001

diff --git a/build.ts b/build.ts
index fcb59e6..a7f6bdf 100755
--- a/build.ts
+++ b/build.ts
@@ -18,8 +18,14 @@ const spritesPath = {
   "sprite_wall_end": "assets/sprites/wall_end.ppm",
   "sprite_wall_straight": "assets/sprites/wall_straight.ppm",
   "sprite_wall_corner": "assets/sprites/wall_corner.ppm",
-  "sprite_robot": "assets/sprites/robot.ppm",
-  "sprite_ghost": "assets/sprites/ghost.ppm",
+  "sprite_robot_up": "assets/sprites/robot_up.ppm",
+  "sprite_robot_right": "assets/sprites/robot_right.ppm",
+  "sprite_robot_down": "assets/sprites/robot_down.ppm",
+  "sprite_robot_left": "assets/sprites/robot_left.ppm",
+  "sprite_ghost_up": "assets/sprites/ghost_up.ppm",
+  "sprite_ghost_right": "assets/sprites/ghost_right.ppm",
+  "sprite_ghost_down": "assets/sprites/ghost_down.ppm",
+  "sprite_ghost_left": "assets/sprites/ghost_left.ppm",
   "sprite_coin": "assets/sprites/coin.ppm",
 };
 
diff --git a/src/consts/game.asm b/src/consts/game.asm
index 9ef3ae8..f73bb21 100644
--- a/src/consts/game.asm
+++ b/src/consts/game.asm
@@ -2,18 +2,3 @@ pub const game.direction_up = 0
 pub const game.direction_right = 1
 pub const game.direction_down = 2
 pub const game.direction_left = 3
-pub const game.direction_still = 4
-
-/*
-; 1_000_000_000 nano second = 0x0000_0000_3B9A_CA00
-pub const game.tick_duration_0 = 0xCA00
-pub const game.tick_duration_1 = 0x3B9A
-pub const game.tick_duration_2 = 0x0000
-pub const game.tick_duration_3 = 0x0000
-*/
-
-; 0.5 second = 500_000_000 nano second = 0x0000_0000_1DCD_6500
-pub const game.tick_duration_0 = 0x6500
-pub const game.tick_duration_1 = 0x1DCD
-pub const game.tick_duration_2 = 0x0000
-pub const game.tick_duration_3 = 0x0000
\ No newline at end of file
diff --git a/src/consts/sprites.asm b/src/consts/sprites.asm
index 8c6f485..e156bc8 100644
--- a/src/consts/sprites.asm
+++ b/src/consts/sprites.asm
@@ -7,12 +7,23 @@ pub const sprites.rotation_90 = 1
 pub const sprites.rotation_180 = 2
 pub const sprites.rotation_270 = 3
 
-pub const sprites.empty = 0
+pub const sprites.empty = 0 ; must stay 0 (some code avoid addition when it knows the tile is empty)
 pub const sprites.unimplemented = 1
 pub const sprites.wall_end = 2
 pub const sprites.wall_straight = 3
 pub const sprites.wall_corner = 4
+
 pub const sprites.robot = 5
-pub const sprites.ghost = 6
-pub const sprites.coin = 7
-pub const sprites.max = 7 ; for lookup table
+pub const sprites.robot_up = 5
+pub const sprites.robot_right = 6
+pub const sprites.robot_down = 7
+pub const sprites.robot_left = 8
+
+pub const sprites.ghost = 9
+pub const sprites.ghost_up = 9
+pub const sprites.ghost_right = 10
+pub const sprites.ghost_down = 11
+pub const sprites.ghost_left = 12
+
+pub const sprites.coin = 13
+pub const sprites.max = 13 ; for lookup table
diff --git a/src/lib/drawing.asm b/src/lib/drawing.asm
index 1f7b553..1634fb4 100644
--- a/src/lib/drawing.asm
+++ b/src/lib/drawing.asm
@@ -41,6 +41,58 @@ pub drawing.draw_whole_map:
 
     ret
 
+/*	Draw the tile corresponding to the given coordinate with it's map content
+
+	Inputs:
+		r1, r2: Map coordinates x, y
+
+	Locals:
+		r3: tile value / sprite id / sprite address offset
+		r9: pointer
+		r13: screen address
+*/
+pub drawing.clear_tile:
+	push r1
+	push r2
+	push r3
+	push r9
+	push r13
+
+	add r9, r1, map
+	push r2
+	pub drawing.clear_tile_row_loop:
+		cmp r2, 0
+		je drawing.clear_tile_row_loop_end
+		sub r2, r2, 1
+		add r9, r9, map.width
+		jmp drawing.clear_tile_row_loop
+	pub drawing.clear_tile_row_loop_end:
+	pop r2
+
+	load_8 r3, [r9]
+	cmp r3, map.tiles.coin
+	add r9, zr, ptr.textures_addresses
+	jne drawing.clear_tile_get_screen_address
+	; coin
+	mov r3, sprites.coin
+	lsl r3, r3, arch.instruction_increment_shift
+	add r9, r9, r3
+
+	pub drawing.clear_tile_get_screen_address:
+	call get_tile_address
+
+	mov r1, r13
+	load_32 r2, [r9]
+	mov r3, sprites.rotation_0
+	call draw_sprite
+
+	pop r13
+	pop r9
+	pop r3
+	pop r2
+	pop r1
+	ret
+
 /* Return the top-left pixel address of the tile at the given map coordinates
 
 	Inputs:
@@ -100,6 +152,7 @@ get_tile_address:
 	pop r3
 	ret
 
+
 /* Get address of given sprite id
 
 	Inputs:
diff --git a/src/lib/u64.asm b/src/lib/u64.asm
new file mode 100644
index 0000000..a0d8e6b
--- /dev/null
+++ b/src/lib/u64.asm
@@ -0,0 +1,18 @@
+/*  Add two unsigned 64 bit
+
+    Input:
+        r1, r2: A.high, A.low
+        r3, r4: B.high, B.low
+
+    Output:
+        r5, r6: C.high, C.low
+*/
+pub u64.add:
+    add r5, r1, r3
+    add r6, r2, r4
+    cmp r6, r2
+    jae u64.add_no_low_overflow
+    add r5, r5, 1 ; overflow
+
+    pub u64.add_no_low_overflow:
+    ret
\ No newline at end of file
diff --git a/src/main.asm b/src/main.asm
index 9282b9c..d57c8b0 100644
--- a/src/main.asm
+++ b/src/main.asm
@@ -17,10 +17,34 @@ include sections/init_timers
 
 game_loop:
     include sections/handle_event
-    include sections/characters_movement
+
+    /*
+    For all timers:
+        r1, r2: tick duration high, low
+        r7, r8: now high, low
+    */
+    add r9, zr, ptr.tick_duration_high
+    load_32 r1, [r9]
+    add r9, zr, ptr.tick_duration_low
+    load_32 r2, [r9]
+    time_0 r8
+    time_1 r7
+
+    push r1
+    push r2
+    push r7
+    push r8
+    include sections/timer_robot
+    pop r8
+    pop r7
+    pop r2
+    pop r1
+
+    include sections/timer_ghost
 
 jmp game_loop
 
+include lib/u64
 include lib/game
 include lib/drawing
 include lib/sprite_rotation
@@ -30,8 +54,14 @@ include dist/placeholder
 include dist/wall_end
 include dist/wall_straight
 include dist/wall_corner
-include dist/robot
-include dist/ghost
+include dist/robot_up
+include dist/robot_right
+include dist/robot_down
+include dist/robot_left
+include dist/ghost_up
+include dist/ghost_right
+include dist/ghost_down
+include dist/ghost_left
 include dist/coin
 
 include dist/map
diff --git a/src/reserved_space.asm b/src/reserved_space.asm
index f513191..2540222 100644
--- a/src/reserved_space.asm
+++ b/src/reserved_space.asm
@@ -5,8 +5,14 @@ U32 0 ; placeholder
 U32 0 ; wall_end
 U32 0 ; wall_straight
 U32 0 ; wall_corner
-U32 0 ; robot
-U32 0 ; ghost
+U32 0 ; robot up
+U32 0 ; robot right
+U32 0 ; robot down
+U32 0 ; robot left
+U32 0 ; ghost up
+U32 0 ; ghost right
+U32 0 ; ghost down
+U32 0 ; ghost left
 U32 0 ; coin
 
 ; 0.5 second = 500_000_000 nano second = 0x0000_0000_1DCD_6500
@@ -17,8 +23,11 @@ pub ptr.tick_duration_low:  U32 0x1DCD_6500
 ; pub ptr.tick_duration_high: U32 0x0000_0000
 ; pub ptr.tick_duration_low:  U32 0x3B9A_CA00
 
-pub ptr.next_tick_high: U32 0
-pub ptr.next_tick_low: U32 0
+pub ptr.timer_robot_next_tick_high: U32 0x0000_0000
+pub ptr.timer_robot_next_tick_low: U32 0x1DCD_6500
+
+pub ptr.timer_ghost_next_tick_high: U32 0
+pub ptr.timer_ghost_next_tick_low: U32 0
 
 pub ptr.state_robot:
 U8 0 ; x coord
diff --git a/src/sections/characters_movement.asm b/src/sections/characters_movement.asm
deleted file mode 100644
index b5afced..0000000
--- a/src/sections/characters_movement.asm
+++ /dev/null
@@ -1,231 +0,0 @@
-/*  Elapsed time check
-
-    r1: address
-    r2: now low / delay low
-    r3: now high / delay high
-    r4: next tick low
-    r5: next tick high
-*/
-time_0 r2
-time_1 r3
-
-add r1, zr, ptr.next_tick_low
-load_32 r4, [r1]
-add r1, zr, ptr.next_tick_high
-load_32 r5, [r1]
-
-cmp r3, r5
-jb game_loop
-ja update_next_tick
-cmp r2, r4
-jb game_loop
-
-update_next_tick:
-add r1, zr, ptr.tick_duration_low
-load_32 r2, [r1]
-add r1, zr, ptr.tick_duration_high
-load_32 r3, [r1]
-add r4, r4, r2
-add r5, r5, r3
-cmp r4, r2
-jae store_next_tick
-add r5, r5, 1
-
-store_next_tick:
-add r1, zr, ptr.next_tick_low
-store_32 [r1], r4
-add r1, zr, ptr.next_tick_high
-store_32 [r1], r5
-
-
-/*  Robot movement
-
-    r1 = robot's state address
-    r2 = x
-    r3 = y
-    r4 = direction
-    r5 = new x
-    r6 = new y
-    r7 = new position address
-    r8 = new position content
-    r9 = jump address
-*/
-add r1, zr, ptr.state_robot
-load_8 r2, [r1]
-add r1, r1, 1
-load_8 r3, [r1]
-add r1, r1, 1
-load_8 r4, [r1]
-
-mov r5, r2
-mov r6, r3
-
-lsl r9, r4, 3 ; 2 * instruction size = 8
-add r9, r9, game_loop_robot_movement_jump_table_start
-jmp r9
-
-game_loop_robot_movement_jump_table_start:
-; direction_up
-sub r6, r6, 1
-jmp game_loop_robot_movement_try_move
-; direction_right
-add r5, r5, 1
-jmp game_loop_robot_movement_try_move
-; direction_down
-add r6, r6, 1
-jmp game_loop_robot_movement_try_move
-; direction_left
-sub r5, r5, 1
-jmp game_loop_robot_movement_try_move
-; direction_still
-jmp game_loop_robot_movement_none
-
-game_loop_robot_movement_try_move:
-push r2
-mov r1, r5
-mov r2, r6
-call game.get_tile_address_from_map_coord
-mov r7, r13
-pop r2
-
-/*
-    Collision handling
-*/
-load_8 r8, [r7]
-cmp r8, map.tiles.wall
-jne game_loop_robot_movement_some
-; hit wall
-add r1, zr, ptr.state_robot
-add r1, r1, 2
-mov r4, game.direction_still
-store_8 [r1], r4
-jmp game_loop_robot_movement_none
-
-game_loop_robot_movement_some:
-; TODO: handle coin and empty differently
-mov r8, map.tiles.empty
-store_8 [r7], r8
-
-add r1, zr, ptr.state_robot
-store_8 [r1], r5
-add r1, r1, 1
-store_8 [r1], r6
-
-; clear old position
-mov r1, r2
-mov r2, r3
-mov r3, sprites.rotation_0
-mov r4, sprites.empty
-call drawing.draw_sprite_at_map_coord
-
-; draw robot on new position
-mov r1, r5
-mov r2, r6
-mov r3, sprites.rotation_0
-mov r4, sprites.robot
-call drawing.draw_sprite_at_map_coord
-
-
-game_loop_robot_movement_none:
-
-/*  Ghost movement
-
-    r1: ghost's state address
-    r2: x
-    r3: y
-    r4: direction
-    r5: x increment
-    r6: y increment
-    r7: new x
-    r8: new y
-    r9: new position address
-    r10: new position content
-    r11: jump address
-*/
-add r1, zr, ptr.state_ghost
-load_8 r2, [r1]
-add r1, r1, 1
-load_8 r3, [r1]
-add r1, r1, 1
-load_8 r4, [r1]
-
-mov r5, 0
-mov r6, 0
-
-lsl r11, r4, 3 ; 2 * instruction size = 8
-add r11, r11, game_loop_ghost_movement_jump_table_start
-jmp r11
-
-game_loop_ghost_movement_jump_table_start:
-; direction_up
-sub r6, r6, 1
-jmp game_loop_ghost_movement_make_move
-; direction_right
-add r5, r5, 1
-jmp game_loop_ghost_movement_make_move
-; direction_down
-add r6, r6, 1
-jmp game_loop_ghost_movement_make_move
-; direction_left
-sub r5, r5, 1
-;jmp game_loop_ghost_movement_make_move
-; direction_still (should never happen)
-
-game_loop_ghost_movement_make_move:
-add r7, r2, r5
-add r8, r3, r6
-add r1, zr, ptr.state_ghost
-store_8 [r1], r7
-add r1, r1, 1
-store_8 [r1], r8
-
-; get tile at previous position
-push r2
-mov r1, r2
-mov r2, r3
-call game.get_tile_address_from_map_coord
-mov r9, r13
-pop r2
-
-; draw tile at previous position
-load_8 r1, [r9]
-cmp r1, map.tiles.coin
-je game_loop_ghost_movement_old_tile_coin
-; old tile empty
-mov r4, sprites.empty
-jmp game_loop_ghost_movement_draw_old_tile
-game_loop_ghost_movement_old_tile_coin:
-mov r4, sprites.coin
-
-game_loop_ghost_movement_draw_old_tile:
-mov r1, r2
-mov r2, r3
-mov r3, sprites.rotation_0
-call drawing.draw_sprite_at_map_coord
-
-; draw ghost on new position
-mov r1, r7
-mov r2, r8
-mov r3, sprites.rotation_0
-mov r4, sprites.ghost
-call drawing.draw_sprite_at_map_coord
-
-/*
-    Check ahead for direction change
-*/
-add r1, r7, r5
-add r2, r8, r6
-call game.get_tile_address_from_map_coord
-
-load_8 r10, [r13]
-cmp r10, map.tiles.wall
-jne game_loop_ghost_movement_end
-; increment direction
-add r1, zr, ptr.state_ghost
-add r1, r1, 2
-load_8 r4, [r1]
-add r4, r4, 1
-and r4, r4, 0b11 ; modulo 3
-store_8 [r1], r4
-
-game_loop_ghost_movement_end:
\ No newline at end of file
diff --git a/src/sections/init_ghost_state.asm b/src/sections/init_ghost_state.asm
index 5bb41d0..24321dc 100644
--- a/src/sections/init_ghost_state.asm
+++ b/src/sections/init_ghost_state.asm
@@ -13,5 +13,5 @@ add r6, r6, 1
 store_8 [r6], r5
 
 mov r3, sprites.rotation_0
-mov r4, sprites.ghost
+mov r4, sprites.ghost_down
 call drawing.draw_sprite_at_map_coord
\ No newline at end of file
diff --git a/src/sections/init_robot_state.asm b/src/sections/init_robot_state.asm
index 383244a..9cde727 100644
--- a/src/sections/init_robot_state.asm
+++ b/src/sections/init_robot_state.asm
@@ -13,5 +13,5 @@ add r6, r6, 1
 store_8 [r6], r5
 
 mov r3, sprites.rotation_0
-mov r4, sprites.robot
+mov r4, sprites.robot_down
 call drawing.draw_sprite_at_map_coord
\ No newline at end of file
diff --git a/src/sections/init_sprite_lookup_table.asm b/src/sections/init_sprite_lookup_table.asm
index 1960054..ba5592e 100644
--- a/src/sections/init_sprite_lookup_table.asm
+++ b/src/sections/init_sprite_lookup_table.asm
@@ -35,18 +35,57 @@ lsl r2, r1, arch.instruction_increment_shift
 add r2, r2, ptr.textures_addresses
 add r3, zr, sprite_wall_corner
 store_32 [r2], r3
-; sprite_robot
-add r1, zr, sprites.robot
+
+; sprite_robot_up
+add r1, zr, sprites.robot_up
 lsl r2, r1, arch.instruction_increment_shift
 add r2, r2, ptr.textures_addresses
-add r3, zr, sprite_robot
+add r3, zr, sprite_robot_up
 store_32 [r2], r3
-; sprite_ghost
-add r1, zr, sprites.ghost
+; sprite_robot_right
+add r1, zr, sprites.robot_right
 lsl r2, r1, arch.instruction_increment_shift
 add r2, r2, ptr.textures_addresses
-add r3, zr, sprite_ghost
+add r3, zr, sprite_robot_right
 store_32 [r2], r3
+; sprite_robot_down
+add r1, zr, sprites.robot_down
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_robot_down
+store_32 [r2], r3
+; sprite_robot_left
+add r1, zr, sprites.robot_left
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_robot_left
+store_32 [r2], r3
+
+; sprite_ghost_up
+add r1, zr, sprites.ghost_up
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_ghost_up
+store_32 [r2], r3
+; sprite_ghost_right
+add r1, zr, sprites.ghost_right
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_ghost_right
+store_32 [r2], r3
+; sprite_ghost_down
+add r1, zr, sprites.ghost_down
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_ghost_down
+store_32 [r2], r3
+; sprite_ghost_left
+add r1, zr, sprites.ghost_left
+lsl r2, r1, arch.instruction_increment_shift
+add r2, r2, ptr.textures_addresses
+add r3, zr, sprite_ghost_left
+store_32 [r2], r3
+
 ; sprite_coin
 add r1, zr, sprites.coin
 lsl r2, r1, arch.instruction_increment_shift
diff --git a/src/sections/init_timers.asm b/src/sections/init_timers.asm
index 415be9a..0835cc5 100644
--- a/src/sections/init_timers.asm
+++ b/src/sections/init_timers.asm
@@ -1,18 +1,34 @@
-add r1, zr, ptr.tick_duration_low
-load_32 r2, [r1]
-add r1, zr, ptr.tick_duration_high
-load_32 r3, [r1]
+/*
+    r1, r2: now high, low
+    r3, r4: initial delay high, low
+    r5, r6: next tick high, low
+    r7: pointer
+*/
+time_0 r2
+time_1 r1
 
-time_0 r4
-time_1 r5
-add r4, r4, r2
-add r5, r5, r3
-cmp r4, r2
-jae init_store_next_tick
-add r5, r5, 1 ; overflow
+; Robot
+add r7, zr, ptr.timer_robot_next_tick_high
+load_32 r3, [r7]
+add r7, zr, ptr.timer_robot_next_tick_low
+load_32 r4, [r7]
 
-init_store_next_tick:
-add r1, zr, ptr.next_tick_low
-store_32 [r1], r4
-add r1, zr, ptr.next_tick_high
-store_32 [r1], r5
\ No newline at end of file
+call u64.add
+
+add r7, zr, ptr.timer_robot_next_tick_high
+store_32 [r7], r5
+add r7, zr, ptr.timer_robot_next_tick_low
+store_32 [r7], r6
+
+; Ghost
+add r7, zr, ptr.timer_ghost_next_tick_high
+load_32 r3, [r7]
+add r7, zr, ptr.timer_ghost_next_tick_low
+load_32 r4, [r7]
+
+call u64.add
+
+add r7, zr, ptr.timer_ghost_next_tick_high
+store_32 [r7], r5
+add r7, zr, ptr.timer_ghost_next_tick_low
+store_32 [r7], r6
\ No newline at end of file
diff --git a/src/sections/timer_ghost.asm b/src/sections/timer_ghost.asm
new file mode 100644
index 0000000..b866d58
--- /dev/null
+++ b/src/sections/timer_ghost.asm
@@ -0,0 +1,99 @@
+/*  Timer comparison / update
+    r1, r2: tick duration high, low [IN]
+    r3, r4: next tick high, low
+    r5, r6: tick after this one high, low
+    r7, r8: now high, low [IN]
+    r9: pointer
+*/
+add r9, zr, ptr.timer_ghost_next_tick_high
+load_32 r3, [r9]
+add r9, zr, ptr.timer_ghost_next_tick_low
+load_32 r4, [r9]
+
+cmp r7, r3
+jb timer_ghost.end
+ja timer_ghost.trigger
+cmp r8, r4
+jb timer_ghost.end
+
+pub timer_ghost.trigger:
+; udate next_tick
+call u64.add
+add r9, zr, ptr.timer_ghost_next_tick_high
+store_32 [r9], r5
+add r9, zr, ptr.timer_ghost_next_tick_low
+store_32 [r9], r6
+
+
+/*  Movement
+    r1, r2: x, y
+    r3: rotation
+    r4: direction / sprite id
+    r5, r6: increments x, y
+    r7, r8: [RESERVED]
+    r9: pointer
+    r10: tile content
+    r13: tile address
+*/
+add r9, zr, ptr.state_ghost
+load_8 r1, [r9]
+add r9, r9, 1
+load_8 r2, [r9]
+add r9, r9, 1
+load_8 r4, [r9]
+
+call drawing.clear_tile
+
+mov r5, 0
+mov r6, 0
+
+lsl r9, r4, 3 ; 2 * instruction size = 8
+add r9, r9, timer_ghost.direction_jump_table
+jmp r9
+
+pub timer_ghost.direction_jump_table:
+; direction_up
+sub r6, r6, 1
+jmp timer_ghost.move
+; direction_right
+add r5, r5, 1
+jmp timer_ghost.move
+; direction_down
+add r6, r6, 1
+jmp timer_ghost.move
+; direction_left
+sub r5, r5, 1
+;jmp timer_ghost.move
+
+pub timer_ghost.move:
+add r1, r1, r5
+add r2, r2, r6
+add r9, zr, ptr.state_ghost
+store_8 [r9], r1
+add r9, r9, 1
+store_8 [r9], r2
+
+; draw ghost on new position
+mov r3, sprites.rotation_0
+add r4, r4, sprites.ghost
+call drawing.draw_sprite_at_map_coord
+
+/*
+    Check ahead for direction change
+*/
+add r1, r1, r5
+add r2, r2, r6
+call game.get_tile_address_from_map_coord
+
+load_8 r10, [r13]
+cmp r10, map.tiles.wall
+jne timer_ghost.end
+; increment direction
+add r9, zr, ptr.state_ghost
+add r9, r9, 2
+load_8 r4, [r9]
+add r4, r4, 1
+and r4, r4, 0b11 ; modulo 3
+store_8 [r9], r4
+
+pub timer_ghost.end:
\ No newline at end of file
diff --git a/src/sections/timer_robot.asm b/src/sections/timer_robot.asm
new file mode 100644
index 0000000..419e678
--- /dev/null
+++ b/src/sections/timer_robot.asm
@@ -0,0 +1,99 @@
+/*  Timer comparison / update
+    r1, r2: tick duration high, low [IN]
+    r3, r4: next tick high, low
+    r5, r6: tick after this one high, low
+    r7, r8: now high, low [IN]
+    r9: pointer
+*/
+add r9, zr, ptr.timer_robot_next_tick_high
+load_32 r3, [r9]
+add r9, zr, ptr.timer_robot_next_tick_low
+load_32 r4, [r9]
+
+cmp r7, r3
+jb timer_robot.end
+ja timer_robot.trigger
+cmp r8, r4
+jb timer_robot.end
+
+pub timer_robot.trigger:
+; udate next_tick
+call u64.add
+add r9, zr, ptr.timer_robot_next_tick_high
+store_32 [r9], r5
+add r9, zr, ptr.timer_robot_next_tick_low
+store_32 [r9], r6
+
+
+/*  Movement
+    r1, r2: x, y
+    r3: rotation
+    r4: direction / sprite id
+    r5, r6: increments x, y
+    r7, r8: [RESERVED]
+    r9: pointer
+    r10: tile content
+    r13: tile address
+*/
+add r9, zr, ptr.state_robot
+load_8 r1, [r9]
+add r9, r9, 1
+load_8 r2, [r9]
+add r9, r9, 1
+load_8 r4, [r9]
+
+call drawing.clear_tile
+
+mov r5, 0
+mov r6, 0
+
+lsl r9, r4, 3 ; 2 * instruction size = 8
+add r9, r9, timer_robot.direction_jump_table
+jmp r9
+
+pub timer_robot.direction_jump_table:
+; direction_up
+sub r6, r6, 1
+jmp timer_robot.try_move
+; direction_right
+add r5, r5, 1
+jmp timer_robot.try_move
+; direction_down
+add r6, r6, 1
+jmp timer_robot.try_move
+; direction_left
+sub r5, r5, 1
+;jmp timer_robot.try_move
+
+/*
+    Collision handling
+*/
+pub timer_robot.try_move:
+add r1, r1, r5
+add r2, r2, r6
+call game.get_tile_address_from_map_coord
+load_8 r10, [r13]
+cmp r10, map.tiles.wall
+jne timer_robot.move
+; hit wall -> cancel movement
+sub r1, r1, r5
+sub r2, r2, r6
+jmp timer_robot.draw
+
+pub timer_robot.move:
+; TODO: handle coin and empty differently
+mov r10, map.tiles.empty
+store_8 [r13], r10
+
+add r9, zr, ptr.state_robot
+store_8 [r9], r1
+add r9, r9, 1
+store_8 [r9], r2
+
+pub timer_robot.draw:
+; draw robot on new position
+mov r3, sprites.rotation_0
+add r4, r4, sprites.robot
+call drawing.draw_sprite_at_map_coord
+
+pub timer_robot.end:
\ No newline at end of file