boot: display rainbow on boot

boot/CMakeLists.txt

@@ -2,6 +2,8 @@
 
 add_library(gay_boot STATIC)
 target_include_directories(gay_boot PRIVATE ${GAY_INCLUDE_DIRS})
+target_compile_definitions(gay_boot PUBLIC ${GAY_KERNEL_DEFINITIONS})
+target_link_libraries(gay_boot PRIVATE c gay_kernel)
 
 target_sources(gay_boot PRIVATE
     multiboot.S

boot/boot.c

@@ -1,10 +1,167 @@
 /* See the end of this file for copyright and license terms. */
 
 #include <multiboot.h>
+#include <string.h>
+
+#include <gay/kprintf.h>
 #include <gay/types.h>
+#include <gay/util.h>
+
+enum vga_color {
+	VGA_COLOR_BLACK		= 0,
+	VGA_COLOR_BLUE		= 1,
+	VGA_COLOR_GREEN		= 2,
+	VGA_COLOR_CYAN		= 3,
+	VGA_COLOR_RED		= 4,
+	VGA_COLOR_MAGENTA	= 5,
+	VGA_COLOR_BROWN		= 6,
+	VGA_COLOR_LIGHT_GREY	= 7,
+	VGA_COLOR_DARK_GREY	= 8,
+	VGA_COLOR_LIGHT_BLUE	= 9,
+	VGA_COLOR_LIGHT_GREEN	= 10,
+	VGA_COLOR_LIGHT_CYAN	= 11,
+	VGA_COLOR_LIGHT_RED	= 12,
+	VGA_COLOR_LIGHT_MAGENTA	= 13,
+	VGA_COLOR_LIGHT_BROWN	= 14,
+	VGA_COLOR_WHITE 	= 15,
+};
+
+#define FB_ADDRESS 0xb8000
+#define FB_LINES 24
+#define FB_COLS 80
+
+struct fb_cell {
+	u8 c;
+	enum vga_color fg:4;
+	enum vga_color bg:4;
+};
+
+/* struct fb_cell gets aligned to 4 bytes for some reason, so we need to use u16 internally */
+static volatile u16 *const framebuffer = (volatile u16 *)FB_ADDRESS;
+/** @brief current line in the framebuffer */
+static unsigned int fb_line;
+/** @brief current column in the framebuffer */
+static unsigned int fb_col;
+/** @brief current background color */
+enum vga_color fb_background;
+/** @brief current foreground color */
+enum vga_color fb_foreground;
+
+static inline volatile struct fb_cell *cell_at(unsigned int line, unsigned int col)
+{
+	return (volatile struct fb_cell *)&framebuffer[line * FB_COLS + col];
+}
+#define current_cell (cell_at(fb_line, fb_col))
+
+static void fb_newline(void)
+{
+	fb_col = 0;
 
-void _boot(u32 magic, u32 address)
+	if (fb_line == FB_LINES - 1) {
+		u8 *first_row = (u8 *)cell_at(0, 0);
+		u8 *second_row = (u8 *)cell_at(0, 1);
+		u8 *last_row_end = (u8 *)cell_at(FB_LINES, FB_COLS);
+		memmove(first_row, second_row, last_row_end - second_row);
+	} else {
+		fb_line++;
+	}
+}
+
+static ssize_t fb_write(struct kprintf_renderer *renderer, const void *buf, size_t size)
 {
+	ssize_t ret = 0;
+	const u8 *s = buf;
+
+	while (size > s - (const u8 *)buf) {
+		u8 c = *s++;
+		ret++;
+
+		if (fb_col == FB_COLS)
+			fb_newline();
+
+		if (c == '\n') {
+			fb_newline();
+			continue;
+		}
+
+		current_cell->c = c;
+		current_cell->fg = fb_foreground;
+		current_cell->bg = fb_background;
+
+		fb_col++;
+	}
+
+	return ret;
+}
+
+static ssize_t fb_flush(struct kprintf_renderer *renderer)
+{
+	return 0;
+}
+
+static struct kprintf_renderer fb_kprintf_renderer = {
+	.write = fb_write,
+	.flush = fb_flush,
+};
+
+static void cls(void)
+{
+	for (unsigned int l = 0; l < FB_LINES; l++) {
+		for (unsigned int c = 0; c < FB_COLS; c++) {
+			cell_at(l, c)->c = '\0';
+			cell_at(l, c)->fg = fb_foreground;
+			cell_at(l, c)->bg = fb_background;
+		}
+	}
+}
+
+static void vga_init(enum vga_color fg, enum vga_color bg)
+{
+	fb_line = 0;
+	fb_col = 0;
+	fb_foreground = VGA_COLOR_LIGHT_GREY;
+	fb_background = VGA_COLOR_BLACK;
+
+	cls();
+}
+
+static void print_gay_propaganda(void)
+{
+	static const enum vga_color rainbow[] = {
+		VGA_COLOR_RED,
+		VGA_COLOR_LIGHT_RED,
+		VGA_COLOR_LIGHT_BROWN,
+		VGA_COLOR_LIGHT_GREEN,
+		VGA_COLOR_LIGHT_CYAN,
+		VGA_COLOR_BLUE,
+	};
+
+	enum vga_color bg_before = fb_background;
+	enum vga_color fg_before = fb_foreground;
+	for (int i = 0; i < ARRAY_SIZE(rainbow); i++) {
+		fb_background = rainbow[i];
+		for (int i = 0; i < FB_COLS; i++)
+			fb_write(NULL, " ", 1);
+	}
+	fb_background = bg_before;
+
+	kprintf("\nWelcome to ");
+	const char *gaybsd = "GayBSD";
+	for (const char *tmp = gaybsd; *tmp != '\0'; tmp++) {
+		fb_foreground = rainbow[tmp - gaybsd];
+		kprintf("%c", *tmp);
+	}
+	fb_foreground = fg_before;
+	kprintf(", be gay do crime!");
+}
+
+void _boot(u32 magic, void *address)
+{
+	kprintf_set_renderer(&fb_kprintf_renderer);
+	vga_init(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
+
+	print_gay_propaganda();
+
 	while (1);
 }
 

include/multiboot.h

@@ -150,7 +150,7 @@ struct mb2_mmap_entry {
 
 	u32 zero;
 };
-typedef struct mb2_mmap_entry multiboot_memory_map_t;
+typedef struct mb2_mmap_entry mb2_memory_map_t;
 
 struct mb2_tag {
 	u32 type;