initial commit working tile demo

4 files changed, 311 insertions, 0 deletions

diff --git a/source/input.hpp b/source/input.hpp
new file mode 100644
index 0000000..2a2a3a2
--- /dev/null
+++ b/source/input.hpp
@@ -0,0 +1,45 @@
+#include "types.hpp"
+
+
+
+typedef u16 KeyFlags;
+
+enum Key : KeyFlags {
+	A      = 0x0001,
+	B      = 0x0002,
+	Select = 0x0004,
+	Start  = 0x0008,
+	Right  = 0x0010,
+	Left   = 0x0020,
+	Up     = 0x0040,
+	Down   = 0x0080,
+	R      = 0x0100,
+	L      = 0x0200,
+};
+
+constexpr KeyFlags KEY_MASK = 0x03FF;
+
+volatile KeyFlags* const REG_KEYINPUT = reinterpret_cast<volatile KeyFlags*>(0x04000130);
+
+static inline KeyFlags &keyflags_curr() {
+	static KeyFlags keybits_curr = 0;
+	return keybits_curr;
+}
+
+static inline KeyFlags &keyflags_prev() {
+	static KeyFlags keybits_prev = 0;
+	return keybits_prev;
+}
+
+static inline void keyflags_poll() {
+	KeyFlags &prev = keyflags_prev();
+	KeyFlags &curr = keyflags_curr();
+
+	prev = curr;
+	curr = ~*REG_KEYINPUT & KEY_MASK;
+}
+
+static inline bool key_is_down(Key key)  { return  keyflags_curr() & key; }
+static inline bool key_is_up(Key key)    { return ~keyflags_curr() & key; }
+static inline bool key_was_down(Key key) { return  keyflags_prev() & key; }
+static inline bool key_was_up(Key key)   { return ~keyflags_prev() & key; }
diff --git a/source/main.cpp b/source/main.cpp
new file mode 100644
index 0000000..ec6be22
--- /dev/null
+++ b/source/main.cpp
@@ -0,0 +1,57 @@
+#include "types.hpp"
+#include "util.hpp"
+#include "input.hpp"
+
+ScreenEntry *bg0_map = screenblock_mem[28];
+
+void bad_vsync() {
+	while (*REG_VCOUNT >= 160);
+	while (*REG_VCOUNT < 160);
+}
+
+int main() {
+	auto bg_flags = BGControlFlags()
+		.set_charblock_base(0)
+		.set_screenblock_base(0)
+		.set_size(BGControlSize::Regular_64x64);
+
+	set_bg_control(0, bg_flags);
+	set_bg_offsets(0, 0, 0);
+
+	const Tile4 tiles[2] = {
+		{{0x11111111, 0x01111111, 0x01111111, 0x01111111, 0x01111111, 0x01111111, 0x01111111, 0x00000001}},
+		{{0x00000000, 0x00100100, 0x01100110, 0x00011000, 0x00011000, 0x01100110, 0x00100100, 0x00000000}},
+	};
+
+	set_tile(0, 0, tiles[0]);
+	set_tile(0, 1, tiles[1]);
+
+	set_bg_palette(0, 1, Color::from_rgb(31,  0,  0));
+	set_bg_palette(1, 1, Color::from_rgb(31,  0,  0));
+	set_bg_palette(2, 1, Color::from_rgb(31,  0,  0));
+	set_bg_palette(3, 1, Color::from_rgb(31,  0,  0));
+
+	ScreenEntry *screen_entry_ptr = bg0_map;
+	for (int i = 0; i < 4; i++) {
+		for (int j = 0; j < 32*32; j++) {
+			*screen_entry_ptr++ = ScreenEntry().set_palette_bank(i);
+		}
+	}
+
+	set_display_control(Mode0, BG0);
+
+	s16 x = 0, y = 0;
+	while (1) {
+		bad_vsync();
+		keyflags_poll();
+
+		if (key_is_down(Key::Left))  x -= 1;
+		if (key_is_down(Key::Right)) x += 1;
+		if (key_is_down(Key::Up))    y -= 1;
+		if (key_is_down(Key::Down))  y += 1;
+
+		set_bg_offsets(0, x, y);
+	}
+
+	return 0;
+}
diff --git a/source/types.hpp b/source/types.hpp
new file mode 100644
index 0000000..222b11c
--- /dev/null
+++ b/source/types.hpp
@@ -0,0 +1,18 @@
+#ifndef TYPES_HPP
+#define TYPES_HPP
+
+typedef signed char  s8;
+typedef signed short s16;
+typedef signed int   s32;
+
+typedef unsigned char  u8;
+typedef unsigned short u16;
+typedef unsigned int   u32;
+
+typedef volatile unsigned char  vu8;
+typedef volatile unsigned short vu16;
+typedef volatile unsigned int   vu32;
+
+typedef u16 color_t;
+
+#endif
diff --git a/source/util.hpp b/source/util.hpp
new file mode 100644
index 0000000..7b39376
--- /dev/null
+++ b/source/util.hpp
@@ -0,0 +1,191 @@
+#ifndef UTIL_HPP
+#define UTIL_HPP
+
+#include "types.hpp"
+#include <assert.h>
+#include <type_traits>
+
+constexpr u32 SCREEN_WIDTH  = 240;
+constexpr u32 SCREEN_HEIGHT = 160;
+
+vu16* const REG_VCOUNT = reinterpret_cast<vu16*>(0x04000006);
+
+enum DisplayControlMode : u16 {
+	Mode0 = 0x0000,
+	Mode1 = 0x0001,
+	Mode2 = 0x0002,
+	Mode3 = 0x0003,
+	Mode4 = 0x0004,
+	Mode5 = 0x0005,
+};
+
+enum DisplayControlLayer : u16 {
+	BG0 = 0x0100,
+	BG1 = 0x0200,
+	BG2 = 0x0400,
+	BG3 = 0x0800,
+	BG4 = 0x1000,
+};
+
+typedef u16 DisplayControlFlags;
+
+constexpr DisplayControlFlags operator|(DisplayControlMode mode, DisplayControlLayer layer) {
+	return static_cast<DisplayControlFlags>(static_cast<u16>(mode) | static_cast<u16>(layer));
+}
+
+static inline void set_display_control(DisplayControlMode mode, DisplayControlLayer layer) {
+	static volatile DisplayControlFlags* const display_control = reinterpret_cast<DisplayControlFlags*>(0x04000000);
+	*display_control = mode | layer;
+}
+
+enum BGControlColorMode : u16 {
+	Mode_4bpp = 0x0000,
+	Mode_8bpp = 0x0080,
+};
+
+enum BGControlSize : u16 {
+	Regular_32x32  = 0x0000,
+	Regular_64x32  = 0x4000,
+	Regular_32x64  = 0x8000,
+	Regular_64x64  = 0xc000,
+	Affine_16x16   = 0x0000,
+	Affine_32x32   = 0x4000,
+	Affine_64x64   = 0x8000,
+	Affine_128x128 = 0xc000,
+};
+
+struct BGControlFlags {
+	u16 flags;
+
+	constexpr BGControlFlags() : flags(0) {}
+
+	constexpr BGControlFlags &set_priority(u16 priority) {
+		assert(priority < 4);
+		this->flags = (this->flags & 0xfffc) | priority;
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_charblock_base(u16 block) {
+		assert(block < 4);
+		this->flags = (this->flags & 0xfff3) | (block << 2);
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_mosaic(u16 enabled) {
+		this->flags = (this->flags & 0xffbf) | (!!enabled << 6);
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_color_mode(BGControlColorMode mode) {
+		this->flags = (this->flags & 0xff7f) | mode;
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_screenblock_base(u16 block) {
+		assert(block < 32);
+		this->flags = (this->flags & 0xe0ff) | (block << 8);
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_affine_wrapping(u16 enabled) {
+		this->flags = (this->flags & 0xdfff) | (!!enabled << 13);
+		return *this;
+	}
+
+	constexpr BGControlFlags &set_size(BGControlSize size) {
+		this->flags = (this->flags & 0x3fff) | size;
+		return *this;
+	}
+
+	constexpr operator u16() const { return this->flags; }
+};
+
+static inline void set_bg_control(u16 bg, BGControlFlags flags) {
+	assert(bg < 4);
+
+	vu16* const reg = reinterpret_cast<vu16*>(0x04000008 + 2*bg);
+	*reg = flags;
+}
+
+static inline void set_bg_offsets(u16 bg, u16 h_offset, u16 v_offset) {
+	vu16* const h_reg = reinterpret_cast<vu16*>(0x04000010 + 4*bg);
+	vu16* const v_reg = reinterpret_cast<vu16*>(0x04000012 + 4*bg);
+
+	*h_reg = h_offset;
+	*v_reg = v_offset;
+}
+
+struct Color {
+	u16 data;
+
+	static constexpr Color from_rgb(u16 r, u16 g, u16 b) {
+		assert(r < 32 && g < 32 && b < 32);
+		return Color { .data = u16(r | (g << 5) | (b << 10)) };
+	}
+};
+
+typedef Color PaletteBank[16];
+
+struct Tile4 { u32 data[8]; };
+typedef Tile4 CharBlock4[512];
+
+template <typename T>
+static inline void volatile_copy(volatile T* dst, const T* src) {
+	using U = std::conditional_t<(sizeof(T) % sizeof(u32) == 0) && (alignof(T) % alignof(u32) == 0), u32, u16>;
+	static_assert(sizeof(T) % sizeof(U) == 0);
+	static_assert(alignof(T) % alignof(U) == 0);
+	auto *d = reinterpret_cast<volatile U*>(dst);
+	auto *s = reinterpret_cast<const U*>(src);
+	for (unsigned i = 0; i < sizeof(T) / sizeof(U); i++) {
+		d[i] = s[i];
+	}
+}
+
+static inline void set_tile(u16 block, u16 index, const Tile4 &tile) {
+	// TODO bounds check
+	volatile CharBlock4 *const blocks = reinterpret_cast<volatile CharBlock4*>(0x06000000);
+	volatile_copy(&blocks[block][index], &tile);
+}
+
+static inline void set_bg_palette(u32 bank, u32 index, const Color &color) {
+	volatile PaletteBank *const banks = reinterpret_cast<volatile PaletteBank*>(0x05000000);
+	volatile_copy(&banks[bank][index], &color);
+}
+
+// pair of screen entry bytes
+struct ScreenEntry {
+	u16 data;
+
+	constexpr ScreenEntry() : data(0) {}
+	constexpr ScreenEntry &set_tile_index(u16 tid) {
+		assert(tid < 1024);
+		this->data = (this->data & ~0x03ff) | tid;
+		return *this;
+	}
+
+	constexpr ScreenEntry &set_hflip(u16 flip) {
+		this->data = (this->data & ~0x0400) | (!!flip << 10);
+		return *this;
+	}
+
+	constexpr ScreenEntry &set_vflip(u16 flip) {
+		this->data = (this->data & ~0x0800) | (!!flip << 11);
+		return *this;
+	}
+
+	constexpr ScreenEntry &set_palette_bank(u16 bank) {
+		assert(bank < 16);
+		this->data = (this->data & ~0xf000) | (bank << 12);
+		return *this;
+	}
+
+	constexpr operator u16() const { return this->data; }
+};
+
+typedef ScreenEntry ScreenBlock[1024];
+
+CharBlock4 *const tile4_mem = reinterpret_cast<CharBlock4*>(0x06000000);
+PaletteBank *const palette_bg_bank = reinterpret_cast<PaletteBank*>(0x05000000);
+ScreenBlock *const screenblock_mem = reinterpret_cast<ScreenBlock*>(0x06000000);
+
+#endif