Intial commit of tinyboot

Makefile

@@ -0,0 +1,82 @@
+ifeq ($(strip $(V)),)
+	E= @echo
+	Q= @
+else
+	E = @\#
+	Q =
+endif
+
+CC := gcc -m32 
+LD := ld -m elf_i386
+AS := as --32
+
+CFLAGS := -g3 -Werror -ffreestanding -nostdlib -mno-red-zone
+LDFLAGS := -nostdlib -fno-builtin -nostartfiles -nostdinc -nodefaultlibs 
+
+KERNEL := kernel.img
+
+WARNINGS += -Wall
+WARNINGS += -Wcast-align
+WARNINGS += -Wformat=2
+WARNINGS += -Winit-self
+WARNINGS += -Wmissing-declarations
+WARNINGS += -Wmissing-prototypes
+WARNINGS += -Wnested-externs
+WARNINGS += -Wno-system-headers
+WARNINGS += -Wold-style-definition
+WARNINGS += -Wredundant-decls
+WARNINGS += -Wsign-compare
+WARNINGS += -Wstrict-prototypes
+WARNINGS += -Wundef
+WARNINGS += -Wvolatile-register-var
+WARNINGS += -Wwrite-strings
+
+CFLAGS += $(WARNINGS)
+
+OBJS += kernel.o
+OBJS += gdt.o
+OBJS += isr.o
+OBJS += idt.o
+OBJS += mm.o
+OBJS += vm.o
+OBJS += vga.o
+OBJS += timer.o
+OBJS += printk.o
+OBJS += kbd.o
+OBJS += string.o
+OBJS += serial.o
+OBJS += ports.o
+OBJS += vtxprintf.o
+OBJS += boot_log.o
+
+all: $(KERNEL)
+	$(E) "--[ Kernel Built"
+
+DEPS :=$(patsubst %.o, %.d, $(OBJS))
+
+$(KERNEL): $(DEPS) $(OBJS) loader.o
+	$(E) "    LINK 	" $@
+	$(Q) $(LD) -T linker.ld loader.o $(OBJS)  -o $@
+
+loader.o:
+	$(E) "    AS  	" $@
+	$(Q) $(AS) -o loader.o loader.s gdt.s interrupt.s
+
+$(DEPS):
+
+%.d: %.c
+	$(Q) $(CC) -M -MT $(patsubst %.d, %.o, $@) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+$(OBJS):
+
+%.o: %.c
+	$(E) "    CC 		" $@
+	$(Q) $(CC) -c $(CFLAGS) $(LDFLAGS) $< -o $@
+
+
+floppy: $(KERNEL)
+
+clean:
+	$(Q) rm -f $(DEPS) $(OBJS) loader.o $(KERNEL)
+	$(E) "--[ Clean"
+

README.md

@@ -1,4 +1,23 @@
 tinyboot
 ========
 
-tinyboot
+This is a tiny 32 bit kernel that was designed for learning purposes.  The
+main goal in writing this was to create some boiler plate code required
+to get [Composite OS](http://composite.seas.gwu.edu/) to boot nativly.
+
+
+credit
+======
+
+* http://www.jamesmolloy.co.uk/tutorial_html/index.html
+* http://www.kernel.org/
+* http://www.minix3.org/
+* http://wiki.osdev.org/
+* http://www.seas.gwu.edu/~gparmer/composite
+* https://github.com/gparmer/Composite
+
+
+license
+======
+This code is licensed under the GPL version 2.0:
+

bochsrc.txt

@@ -0,0 +1,2 @@
+boot: floppy
+floppya: 1_44="floppy.img", status=inserted

boot_log.c

@@ -0,0 +1,34 @@
+#include "string.h"
+#include "serial.h"
+#include "boot_log.h"
+#include "printk.h"
+
+char boot_buffer[1024] = { '\0' };
+
+static const char * boot_log_msgs[] = {
+    [BOOT_OK]    = "\033[1;32m  OK  ",
+	[BOOT_WARN]  = "\033[1;33m WARN ",
+	[BOOT_ERROR] = "\033[1;31mERROR!",
+};
+
+static const char *last_message = NULL;
+
+void 
+boot_log(const char *s)
+{
+    last_message = s;
+
+    sprintf(boot_buffer, "\033[0m%s\033[1000C\033[8D[ \033[1;34m....\033[0m ]", s);
+    serial__puts(boot_buffer);
+}
+
+void
+boot_log_finish(enum boot_log_level l)
+{
+    if (last_message == NULL)
+        return;
+
+    sprintf(boot_buffer, "\033[1000D\033[0m%s\033[1000C\033[8D[%s\033[0m]\n", last_message, boot_log_msgs[l]);
+    serial__puts(boot_buffer);
+}
+

boot_log.h

@@ -0,0 +1,15 @@
+#ifndef _BOOT_LOG_H_
+#define _BOOT_LOG_H_
+
+enum boot_log_level {
+    BOOT_OK,
+    BOOT_WARN,
+    BOOT_ERROR,
+};
+
+
+void boot_log(const char *s);
+void boot_log_finish(enum boot_log_level l);
+
+
+#endif

div64.h

@@ -0,0 +1,30 @@
+#ifndef __I386_DIV64
+#define __I386_DIV64
+
+/*
+ * do_div() is NOT a C function. It wants to return
+ * two values (the quotient and the remainder), but
+ * since that doesn't work very well in C, what it
+ * does is:
+ *
+ * - modifies the 64-bit dividend _in_place_
+ * - returns the 32-bit remainder
+ *
+ * This ends up being the most efficient "calling
+ * convention" on x86.
+ */
+#define do_div(n,base) ({ \
+	unsigned long __upper, __low, __high, __mod, __base; \
+	__base = (base); \
+	asm("":"=a" (__low), "=d" (__high):"A" (n)); \
+	__upper = __high; \
+	if (__high) { \
+		__upper = __high % (__base); \
+		__high = __high / (__base); \
+	} \
+	asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \
+	asm("":"=A" (n):"a" (__low),"d" (__high)); \
+	__mod; \
+})
+
+#endif

gdt.c

@@ -0,0 +1,68 @@
+#include "types.h"
+#include "gdt.h"
+
+struct gdt_entry {
+    uint16_t limit_low;     // Lower 16 bits of the limit
+    uint16_t base_low;      // Lower 16 bits of the base
+    uint8_t base_middle;    // Next 8 bits of the base
+    uint8_t access;         // Access flags to determine ring
+    uint8_t granularity;    
+    uint8_t base_high;      // Last 8 bits of the base
+} __attribute__((packed));
+
+struct gdt_ptr {
+    uint16_t limit;     // Upper 16 bits of all selecor limits
+    uint32_t base;      // Address of the first gdt entry
+} __attribute__((packed));
+
+
+extern void gdt_flush(uint32_t);
+
+#define NUM_GDT_ENTRIES 5
+
+static struct gdt_entry gdt_entries[NUM_GDT_ENTRIES];
+struct gdt_ptr gdt_ptr;
+
+static void 
+gdt_set_gate(int32_t num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran) {
+
+    /* setup the base address */
+    gdt_entries[num].base_low    = (base & 0xFFFF);
+    gdt_entries[num].base_middle = (base >> 16) & 0xFF;
+    gdt_entries[num].base_high   = (base >> 24) & 0xFF;
+
+    /* Set up the limits */
+    gdt_entries[num].limit_low   = (limit & 0xFFFF);
+    gdt_entries[num].granularity = (limit >> 16) & 0x0F;
+
+    /* Set granularity */
+    gdt_entries[num].granularity |= (gran & 0xF0);
+
+    /* Assign access flags */
+    gdt_entries[num].access = access;
+}
+
+void
+gdt__init(void)
+{
+    gdt_ptr.limit = (sizeof(struct gdt_entry) * NUM_GDT_ENTRIES) - 1;
+    gdt_ptr.base = (uintptr_t)&gdt_entries;
+
+    /* NULL */
+    gdt_set_gate(0, 0, 0, 0, 0);
+
+    /* Code Segemnt */
+    gdt_set_gate(1, 0, 0xFFFFFFFF, 0x9A, 0xCF);
+
+    /* Data Segemnt */
+    gdt_set_gate(2, 0, 0xFFFFFFFF, 0x92, 0xCF);
+
+    /* User mode code */
+    gdt_set_gate(3, 0, 0xFFFFFFFF, 0xFA, 0xCF);
+
+    /* User mode data */
+    gdt_set_gate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF);
+
+    gdt_flush((uintptr_t)&gdt_ptr);
+}
+

gdt.h

@@ -0,0 +1,6 @@
+#ifndef _GDT_H_
+#define _GDT_H_
+
+void gdt__init(void);
+
+#endif

gdt.s

@@ -0,0 +1,21 @@
+.global gdt_flush
+gdt_flush:
+    # Load the GDT
+    mov 4(%esp), %eax
+    lgdt (%eax)
+    mov $0x10, %ax
+    mov %ax, %ds
+    mov %ax, %es
+    mov %ax, %fs
+    mov %ax, %gs
+    mov %ax, %ss
+    ljmp $0x08,$(flush)
+flush:
+    ret
+
+.global idt_flush
+idt_flush:
+    mov 4(%esp), %eax
+    lidt (%eax)
+    ret
+