diff --git a/example/example.mk b/example/example.mk
index 571d1f8..2033a71 100644
--- a/example/example.mk
+++ b/example/example.mk
@@ -963,3 +963,16 @@ BEAR_OBJ = \
 
 example/bear.elf: LDSCRIPT = $(LIB)/main.lds
 example/bear.elf: $(START_OBJ) $(BEAR_OBJ)
+
+FOG_OBJ = \
+	example/fog.o \
+	holly/core.o \
+	holly/region_array.o \
+	holly/background.o \
+	holly/ta_fifo_polygon_converter.o \
+	holly/video_output.o \
+	sh7091/serial.o \
+	$(LIBGCC)
+
+example/fog.elf: LDSCRIPT = $(LIB)/main.lds
+example/fog.elf: $(START_OBJ) $(FOG_OBJ)
diff --git a/example/fog.cpp b/example/fog.cpp
new file mode 100644
index 0000000..0c8db3a
--- /dev/null
+++ b/example/fog.cpp
@@ -0,0 +1,426 @@
+#include <stdint.h>
+
+#include "holly/background.hpp"
+#include "holly/core.hpp"
+#include "holly/core_bits.hpp"
+#include "holly/holly.hpp"
+#include "holly/isp_tsp.hpp"
+#include "holly/region_array.hpp"
+#include "holly/ta_bits.hpp"
+#include "holly/ta_fifo_polygon_converter.hpp"
+#include "holly/ta_global_parameter.hpp"
+#include "holly/ta_parameter.hpp"
+#include "holly/ta_vertex_parameter.hpp"
+#include "holly/texture_memory_alloc3.hpp"
+#include "holly/video_output.hpp"
+
+#include "sh7091/sh7091.hpp"
+#include "sh7091/sh7091_bits.hpp"
+#include "sh7091/serial.hpp"
+#include "sh7091/vbr.hpp"
+
+#include "systembus.hpp"
+#include "systembus_bits.hpp"
+
+#include "memorymap.hpp"
+
+#include "math/vec2.hpp"
+#include "math/vec3.hpp"
+#include "math/vec4.hpp"
+#include "math/mat4x4.hpp"
+
+using vec2 = vec<2, float>;
+using vec3 = vec<3, float>;
+using vec4 = vec<4, float>;
+using mat4x4 = mat<4, 4, float>;
+
+void vbr100()
+{
+  serial::string("vbr100\n");
+  serial::string("expevt ");
+  serial::integer<uint16_t>(sh7091.CCN.EXPEVT);
+  serial::string("intevt ");
+  serial::integer<uint16_t>(sh7091.CCN.INTEVT);
+  serial::string("tra ");
+  serial::integer<uint16_t>(sh7091.CCN.TRA);
+
+  uint32_t spc;
+  uint32_t ssr;
+  asm volatile ("stc spc,%0" : "=r" (spc));
+  asm volatile ("stc ssr,%0" : "=r" (ssr));
+  serial::string("spc ");
+  serial::integer(spc);
+  serial::string("ssr ");
+  serial::integer(ssr);
+
+  while (1);
+}
+
+void vbr400()
+{
+  serial::string("vbr400\n");
+  serial::string("expevt ");
+  serial::integer<uint16_t>(sh7091.CCN.EXPEVT);
+  serial::string("intevt ");
+  serial::integer<uint16_t>(sh7091.CCN.INTEVT);
+  serial::string("tra ");
+  serial::integer<uint16_t>(sh7091.CCN.TRA);
+
+  uint32_t spc;
+  uint32_t ssr;
+  asm volatile ("stc spc,%0" : "=r" (spc));
+  asm volatile ("stc ssr,%0" : "=r" (ssr));
+  serial::string("spc ");
+  serial::integer(spc);
+  serial::string("ssr ");
+  serial::integer(ssr);
+
+  while (1);
+}
+
+static int render_done = 0;
+
+void vbr600()
+{
+  if (sh7091.CCN.EXPEVT == 0 && sh7091.CCN.INTEVT == 0x320) {
+    uint32_t istnrm = system.ISTNRM;
+    uint32_t isterr = system.ISTERR;
+
+    if (isterr) {
+      serial::string("isterr: ");
+      serial::integer<uint32_t>(system.ISTERR);
+    }
+
+    if (istnrm & istnrm::end_of_render_tsp) {
+      system.ISTNRM = istnrm::end_of_render_tsp
+                    | istnrm::end_of_render_isp
+                    | istnrm::end_of_render_video;
+      render_done = 1;
+      return;
+    }
+  }
+
+  serial::string("vbr600\n");
+  serial::string("expevt ");
+  serial::integer<uint16_t>(sh7091.CCN.EXPEVT);
+  serial::string("intevt ");
+  serial::integer<uint16_t>(sh7091.CCN.INTEVT);
+  serial::string("tra ");
+  serial::integer<uint16_t>(sh7091.CCN.TRA);
+
+  serial::string("istnrm: ");
+  serial::integer<uint32_t>(system.ISTNRM);
+  serial::string("isterr: ");
+  serial::integer<uint32_t>(system.ISTERR);
+
+  uint32_t spc;
+  uint32_t ssr;
+  asm volatile ("stc spc,%0" : "=r" (spc));
+  asm volatile ("stc ssr,%0" : "=r" (ssr));
+  serial::string("spc ");
+  serial::integer(spc);
+  serial::string("ssr ");
+  serial::integer(ssr);
+
+  while (1);
+}
+
+void interrupt_init()
+{
+  system.IML2NRM = 0;
+  system.IML2ERR = 0;
+  system.IML2EXT = 0;
+
+  system.IML4NRM = 0;
+  system.IML4ERR = 0;
+  system.IML4EXT = 0;
+
+  system.IML6NRM = 0;
+  system.IML6ERR = 0;
+  system.IML6EXT = 0;
+
+  system.ISTERR = 0xffffffff;
+  system.ISTNRM = 0xffffffff;
+
+  sh7091.CCN.INTEVT = 0;
+  sh7091.CCN.EXPEVT = 0;
+
+  uint32_t vbr = reinterpret_cast<uint32_t>(&__vbr_link_start) - 0x100;
+  serial::string("vbr ");
+  serial::integer<uint32_t>(vbr);
+  serial::string("vbr100 ");
+  serial::integer<uint32_t>(reinterpret_cast<uint32_t>(&vbr100));
+
+  asm volatile ("ldc %0,vbr"
+		:
+		: "r" (vbr));
+
+  uint32_t sr;
+  asm volatile ("stc sr,%0"
+		: "=r" (sr));
+  serial::string("sr ");
+  serial::integer<uint32_t>(sr);
+
+  sr &= ~sh::sr::bl; // BL
+  sr &= ~sh::sr::imask(15); // imask
+
+  serial::string("sr ");
+  serial::integer<uint32_t>(sr);
+
+  asm volatile ("ldc %0,sr"
+		:
+		: "r" (sr));
+}
+
+vec3 square[] = {
+  {0 + 50, 0 + 50, 0.00392156862745098},
+  {640 - 50, 0 + 50, 0.9725490196078431},
+  {640 - 50, 480 - 50, 0.9725490196078431},
+  {0 + 50, 480 - 50, 0.00392156862745098},
+};
+
+vec2 texcoord[] = {
+  {0, 0},
+  {1, 0},
+  {1, 1},
+  {0, 1},
+};
+
+uint32_t offset[] = {
+  0,
+  0xffUL << 24,
+  0xffUL << 24,
+  0
+};
+
+void global_polygon_type_0(ta_parameter_writer& writer,
+                           uint32_t list,
+                           uint32_t cull)
+{
+  const uint32_t parameter_control_word = para_control::para_type::polygon_or_modifier_volume
+                                        | list
+                                        | obj_control::col_type::packed_color
+                                        | obj_control::gouraud
+                                        | obj_control::offset
+                                        | obj_control::texture
+                                        ;
+  const uint32_t isp_tsp_instruction_word = isp_tsp_instruction_word::depth_compare_mode::greater
+                                          | cull;
+
+  const uint32_t tsp_instruction_word = 0
+    //| tsp_instruction_word::fog_control::per_vertex
+    | tsp_instruction_word::fog_control::look_up_table
+                                      | tsp_instruction_word::src_alpha_instr::one
+                                      | tsp_instruction_word::dst_alpha_instr::zero
+                                      | tsp_instruction_word::texture_shading_instruction::modulate
+                                      | tsp_instruction_word::texture_u_size::from_int(8)
+                                      | tsp_instruction_word::texture_v_size::from_int(8)
+                                      ;
+
+  const uint32_t texture_address = texture_memory_alloc.texture.start;
+  const uint32_t texture_control_word = texture_control_word::pixel_format::_565
+                                      | texture_control_word::scan_order::twiddled
+                                      | texture_control_word::texture_address(texture_address / 8);
+
+  writer.append<ta_global_parameter::polygon_type_0>() =
+    ta_global_parameter::polygon_type_0(parameter_control_word,
+                                        isp_tsp_instruction_word,
+                                        tsp_instruction_word,
+                                        texture_control_word,
+                                        0, // data size for sort dma
+                                        0  // next address for sort dma
+                                        );
+}
+
+static inline void render_quad_type_3(ta_parameter_writer& writer,
+                                      vec3 ap,
+                                      vec3 bp,
+                                      vec3 cp,
+                                      vec3 dp,
+                                      vec2 at,
+                                      vec2 bt,
+                                      vec2 ct,
+                                      vec2 dt,
+                                      uint32_t base_color,
+                                      uint32_t aoc,
+                                      uint32_t boc,
+                                      uint32_t coc,
+                                      uint32_t doc)
+{
+  writer.append<ta_vertex_parameter::polygon_type_3>() =
+    ta_vertex_parameter::polygon_type_3(polygon_vertex_parameter_control_word(false),
+                                        ap.x, ap.y, ap.z,
+                                        at.x, at.y,
+                                        base_color,
+                                        aoc);
+
+  writer.append<ta_vertex_parameter::polygon_type_3>() =
+    ta_vertex_parameter::polygon_type_3(polygon_vertex_parameter_control_word(false),
+                                        bp.x, bp.y, bp.z,
+                                        bt.x, bt.y,
+                                        base_color,
+                                        boc);
+
+  writer.append<ta_vertex_parameter::polygon_type_3>() =
+    ta_vertex_parameter::polygon_type_3(polygon_vertex_parameter_control_word(false),
+                                        dp.x, dp.y, dp.z,
+                                        dt.x, dt.y,
+                                        base_color,
+                                        doc);
+
+  writer.append<ta_vertex_parameter::polygon_type_3>() =
+    ta_vertex_parameter::polygon_type_3(polygon_vertex_parameter_control_word(true),
+                                        cp.x, cp.y, cp.z,
+                                        ct.x, ct.y,
+                                        base_color,
+                                        coc);
+}
+
+void transfer_scene(ta_parameter_writer& writer)
+{
+  global_polygon_type_0(writer,
+                        para_control::list_type::opaque,
+                        isp_tsp_instruction_word::culling_mode::no_culling);
+
+  render_quad_type_3(writer,
+                     square[0],
+                     square[1],
+                     square[2],
+                     square[3],
+                     texcoord[0],
+                     texcoord[1],
+                     texcoord[2],
+                     texcoord[3],
+                     0xff00ff00,
+                     offset[0],
+                     offset[1],
+                     offset[2],
+                     offset[3]);
+
+  writer.append<ta_global_parameter::end_of_list>() =
+    ta_global_parameter::end_of_list(para_control::para_type::end_of_list);
+}
+
+void fog_init()
+{
+  // for look-up table mode
+  // 2 ** 0 * 128 = 1.0
+  /*
+  holly.FOG_DENSITY = 0
+    | fog_density::fog_scale_mantissa(128)
+    | fog_density::fog_scale_exponent(0)
+    ;
+  */
+  holly.FOG_DENSITY = 0
+    | fog_density::fog_scale_mantissa(255)
+    | fog_density::fog_scale_exponent(7)
+    ;
+
+  holly.FOG_CLAMP_MIN = 0x0;
+  holly.FOG_CLAMP_MAX = 0xffffffff;
+  holly.FOG_COL_RAM = 0xff0000; // for look-up table mode
+  holly.FOG_COL_VERT = 0xff0000; // red
+
+  for (int i = 0; i < 128; i++) {
+    holly.FOG_TABLE[i] = ((i * 2) << 8) | ((i + 1) * 2);
+  }
+}
+
+void texture_init()
+{
+  volatile uint32_t * base = &texture_memory64[texture_memory_alloc.texture.start / 4];
+  for (int i = 0; i < 8 * 8 / 2; i++) {
+    base[i] = 0xffffffff;
+  }
+}
+
+uint8_t __attribute__((aligned(32))) ta_parameter_buf[1024 * 1024];
+
+void main()
+{
+  serial::init(0);
+
+  interrupt_init();
+
+  constexpr uint32_t ta_alloc = 0
+                              | ta_alloc_ctrl::pt_opb::no_list
+			      | ta_alloc_ctrl::tm_opb::no_list
+                              | ta_alloc_ctrl::t_opb::no_list
+                              | ta_alloc_ctrl::om_opb::no_list
+                              | ta_alloc_ctrl::o_opb::_16x4byte;
+
+  constexpr int render_passes = 1;
+  constexpr struct opb_size opb_size[render_passes] = {
+    {
+      .opaque = 16 * 4,
+      .opaque_modifier = 0,
+      .translucent = 0,
+      .translucent_modifier = 0,
+      .punch_through = 0
+    }
+  };
+
+  holly.SOFTRESET = softreset::pipeline_soft_reset
+		  | softreset::ta_soft_reset;
+  holly.SOFTRESET = 0;
+
+  core_init();
+  fog_init();
+  texture_init();
+
+  system.IML6NRM = istnrm::end_of_render_tsp;
+
+  const int framebuffer_width = 640;
+  const int framebuffer_height = 480;
+  const int tile_width = framebuffer_width / 32;
+  const int tile_height = framebuffer_height / 32;
+
+  for (int i = 0; i < 2; i++) {
+    region_array_multipass(tile_width,
+                           tile_height,
+                           opb_size,
+                           render_passes,
+                           texture_memory_alloc.region_array[i].start,
+                           texture_memory_alloc.object_list[i].start);
+
+    background_parameter2(texture_memory_alloc.background[i].start,
+                          0xff202040);
+  }
+
+  int ta = 0;
+  int core = 0;
+
+  ta_parameter_writer writer = ta_parameter_writer(ta_parameter_buf);
+
+  video_output::set_mode_vga();
+
+  while (1) {
+    ta_polygon_converter_init2(texture_memory_alloc.isp_tsp_parameters[ta].start,
+			       texture_memory_alloc.isp_tsp_parameters[ta].end,
+			       texture_memory_alloc.object_list[ta].start,
+			       texture_memory_alloc.object_list[ta].end,
+			       opb_size[0].total(),
+			       ta_alloc,
+			       tile_width,
+			       tile_height);
+    writer.offset = 0;
+    transfer_scene(writer);
+    ta_polygon_converter_writeback(writer.buf, writer.offset);
+    ta_polygon_converter_transfer(writer.buf, writer.offset);
+    ta_wait_opaque_list();
+
+    render_done = 0;
+    core_start_render2(texture_memory_alloc.region_array[core].start,
+                       texture_memory_alloc.isp_tsp_parameters[core].start,
+                       texture_memory_alloc.background[core].start,
+                       texture_memory_alloc.framebuffer[core].start,
+                       framebuffer_width);
+    while (render_done == 0) {
+      asm volatile ("nop");
+    };
+
+    while (!spg_status::vsync(holly.SPG_STATUS));
+    holly.FB_R_SOF1 = texture_memory_alloc.framebuffer[ta].start;
+    while (spg_status::vsync(holly.SPG_STATUS));
+  }
+}