1 files changed, 115 insertions, 0 deletions
diff --git a/system/kernel.c b/system/kernel.c
new file mode 100644
index 0000000..e8ad3a9
--- /dev/null
+++ b/system/kernel.c
@@ -0,0 +1,115 @@
+/* kernel.c - kernel functions */
+
+#include <system.h>
+#include <console.h>
+
+
+extern unsigned char console_std_attr;
+extern unsigned short console_cur_pos;
+extern unsigned char console_flags;
+
+unsigned char numprint = 0;
+
+#define PRINT_ON if(numprint == 0) { \
+		asm("cli");\
+		console_cursor_off();\
+	}\
+	numprint++
+
+#define PRINT_OFF numprint--;\
+	if(numprint == 0) {\
+		console_cursor_on();\
+		asm("sti");\
+	}
+
+
+void print(unsigned char * text) {
+	print_attr(text, console_std_attr);
+}
+
+void print_attr(unsigned char * text, unsigned char attr) {
+	PRINT_ON;
+	while(*text) {
+		print_char_attr(*text, attr);
+		text++;
+	}
+	PRINT_OFF;
+}
+
+void print_char(unsigned char text) {
+	print_char_attr(text, console_std_attr);
+}
+
+void print_char_attr(unsigned char text, unsigned char attr) {
+	PRINT_ON;
+	switch(text) {
+		case 0x08:		// backspace
+			if(console_cur_pos) console_cur_pos--;
+			break;
+		case 0x09:		// tab
+			console_cur_pos += (8 - (console_cur_pos % 8));
+			break;
+		case 0x0A:		// new line
+			console_cur_pos += (80 - (console_cur_pos % 80));
+			break;
+		case 0x0B:		// home
+		case 0x0C:		// form feed
+			console_cur_pos = 0;
+			asm(
+				"cld\n"
+				"mov $32,%%ax\n"
+				"mov %%ax,%%es\n"
+				"xor %%edi,%%edi\n"
+				"mov %0,%%ah\n"
+				"mov $0x20,%%al\n"
+				"mov $2000,%%ecx\n"
+				"rep stosw"
+				: : "m" (attr)
+			);
+			break;
+		case 0x0D:		// carriage return
+			console_cur_pos -= (console_cur_pos % 80);
+			break;
+		default:
+			ANSI2ASCII(text);
+			asm(
+				"cld\n"
+				"mov $32,%%ax\n"
+				"mov %%ax,%%es\n"
+				"xor %%eax,%%eax\n"
+				"mov %0,%%ax\n"
+				"shl $1,%%eax\n"
+				"mov %%eax,%%edi\n"
+				"mov %1,%%al\n"
+				"mov %2,%%ah\n"
+				"stosw"
+				: : "m" (console_cur_pos), "m" (text), "m" (attr)
+			);
+			console_cur_pos++;
+	}
+	// scroll
+	if(console_cur_pos >= 2000) {
+		console_cur_pos -= 80;
+		asm(
+			"cld\n"
+			"push %%ds\n"
+			
+			"mov $32,%%ax\n"
+			"mov %%ax,%%ds\n"
+			"mov %%ax,%%es\n"
+			"mov $1920,%%ecx\n"
+			"mov $160,%%esi\n"
+			"xor %%edi,%%edi\n"
+			"rep movsw\n"
+			
+			"mov $80,%%cx\n"
+			"mov %%cs:%0,%%ah\n"
+			"mov $0x20,%%al\n"
+			"rep stosw\n"
+			
+			"pop %%ds"
+			: : "m" (console_std_attr)
+		);
+	}
+	PRINT_OFF;
+}