64-bit mode and C kernel.

pdoane · Apr 15, 2012 · 9d9d080 · 9d9d080
1 parent 5e47a73
commit 9d9d080
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Showing 16 changed files with 488 additions and 104 deletions.
diff --git a/Makefile b/Makefile
@@ -1,18 +1,27 @@
 all: all_targets
 
+HOST_SOURCES :=
 TARGETS :=
 INTERMEDIATES :=
 
 include ./module.mk
 include boot/module.mk
+include kernel/module.mk
 include tools/module.mk
 
-CC := gcc
-CFLAGS := -std=c99 -Wall -O
+HOST_CC := gcc
+HOST_CFLAGS := -std=c99 -Wall -O2
+
+CC := x86_64-elf-gcc
+CFLAGS := -std=c99 -nostdlib -nostartfiles -nodefaultlibs -Wall -O2
+LD := x86_64-elf-ld
 
 %.bin: %.asm
 	nasm -f bin -o $@ $<
 
+$(HOST_SOURCES:.c=.o): %.o: %.c
+	$(HOST_CC) -c $(HOST_CFLAGS) $< -o $@
+
 all_targets: $(TARGETS)
 
 clean:

diff --git a/README b/README
@@ -1,8 +1,8 @@
 This is a hobby OS project for learning more about low-level hardware.
 
 Software used:
-- MinGW
-- GCC
+- Cygwin
+- GCC (native + cross-compiler for x86_64-elf)
 - NASM
 - Make
 
@@ -13,10 +13,11 @@ Emulator steps:
 
 Hardware steps:
 
-  Format a FAT16 drive, update the boot sector and copy the loader binary
+  Format a FAT16 drive, update the boot sector and copy the loader and kernel binaries
 
   $ make
   $ tools/set_boot.exe //./<drive letter>: boot/boot.bin
   $ cp boot/loader.bin <drive letter>:
+  $ cp kernel/kernel.bin <drive letter>:
 
   Boot!
diff --git a/TODO b/TODO
@@ -1,5 +1,7 @@
-Loader
 
-- 64-bit mode
-- Execute C-mode kernel
+- Interrupt handlers
+- IRQ
+- Console utilities
+- E820 memory map
 - SMP initialization
+- VM tables
diff --git a/boot/boot.asm b/boot/boot.asm
@@ -1,93 +1,47 @@
+; -------------------------------------------------------------------------------------------------
+; boot.asm
+; -------------------------------------------------------------------------------------------------
+
 [ORG 0x7c00]
 [BITS 16]
 
+%include "boot/defines.asm"
+
 ; -------------------------------------------------------------------------------------------------
 ; Entrypoint for boot loader
 ; in: dl = bootdrive
 entry:
         jmp short loader
         nop
 
-times 0x3b db 0            ; BIOS parameter block
-
-; Bios Parameter Block
-%define boot_sector_base            0x7c00
-%define bpb_oem                     boot_sector_base + 0x03
-%define bpb_bytes_per_sector        boot_sector_base + 0x0b
-%define bpb_sectors_per_cluster     boot_sector_base + 0x0d
-%define bpb_reserved_sector_count   boot_sector_base + 0x0e
-%define bpb_fat_count               boot_sector_base + 0x10
-%define bpb_root_entry_count        boot_sector_base + 0x11
-%define bpb_sector_count            boot_sector_base + 0x13
-%define bpb_media_type              boot_sector_base + 0x15
-%define bpb_sectors_per_fat         boot_sector_base + 0x16
-%define bpb_sectors_per_track       boot_sector_base + 0x18
-%define bpb_head_count              boot_sector_base + 0x1a
-%define bpb_hidden_sector_count     boot_sector_base + 0x1c
-%define bpb_large_sector_count      boot_sector_base + 0x20
-
-; Extended Bios Parameter Block
-%define ebpb_drive_number           boot_sector_base + 0x24
-%define epbp_flags                  boot_sector_base + 0x25
-%define epbp_signature              boot_sector_base + 0x26
-%define epbp_volume_id              boot_sector_base + 0x27
-%define epbp_volume_label           boot_sector_base + 0x2b
-%define epbp_filesystem             boot_sector_base + 0x36
+times 0x3b db 0                     ; BIOS parameter block
 
 loader:
         mov [ebpb_drive_number], dl
         xor ax, ax
         mov ds, ax
         mov es, ax
         mov ss, ax
-        mov sp, 0x7c00
+        mov sp, boot_sector_base
 
-        ; Clear Screen
-        mov ax, 0x3
+        mov ax, 0x3                 ; Clear Screen
         int 0x10
 
-        ; Print loading message
-        mov si, msg_load
+        mov si, msg_load            ; Print loading message
         call bios_print
 
-        ; Find root directory
-        xor eax, eax
-        mov al, [bpb_fat_count]
-        mul word[bpb_sectors_per_fat]
-        add ax, [bpb_reserved_sector_count]
-
-find_loader:
-        mov bx, 0x8000
-        mov di, bx
-        call read_sector
-
-.next_entry:
-        mov cx, 0x0b
-        mov si, filename_loader
-        repe cmpsb                ; compare ds:si with es:di
-        jz load_file
-
-        add di, 0x20
-        and di, -0x20
-        cmp di, [bpb_bytes_per_sector]
-        jnz .next_entry
-
-        mov si, msg_failed
-        call bios_print
-        jmp $
+        call find_root_file
 
 load_file:
         mov ax, [di+0xf]
-        mov bx, 0x8000
+        mov bx, loader_base
 
 .next_cluster:
         call read_cluster
         cmp ax, 0xfff8
         jg .next_cluster
 
-run_loader:
-        mov dl, [ebpb_drive_number]
-        jmp 0:0x8000
+        jmp 0:loader_base           ; Run loader
 
 ; -------------------------------------------------------------------------------------------------
 ; Reads a sector using LBA
@@ -172,13 +126,12 @@ read_cluster:
         shr cx, 4                   ; (root_entry_count * 32) / 512
         add ax, cx
 
-        xor cx, cx
-        mov cl, [bpb_sectors_per_cluster]
+        xor dx, dx
+        mov dl, [bpb_sectors_per_cluster]
 
 .next_sector:
         call read_sector
-        dec cx
-        cmp cx, 0
+        dec dx
         jne .next_sector
 
 .next_cluster:
@@ -189,10 +142,10 @@ read_cluster:
         div word[bpb_bytes_per_sector]
         add ax, [bpb_reserved_sector_count]
 
-        mov bx, 0x7e00
+        mov bx, temp_sector
         call read_sector
 
-        mov bx, 0x7e00
+        mov bx, temp_sector
         add bx, dx
         mov ax, [bx]
         pop bx
@@ -202,6 +155,37 @@ read_cluster:
         pop cx
         ret
 
+; -------------------------------------------------------------------------------------------------
+; Find root file
+; destroys: eax, bx, cx, si, di
+find_root_file:
+        xor eax, eax
+        mov al, [bpb_fat_count]
+        mul word[bpb_sectors_per_fat]
+        add ax, [bpb_reserved_sector_count]
+
+        mov bx, temp_sector
+        mov di, bx
+        call read_sector
+
+.next_entry:
+        mov si, filename
+        mov cx, 0x0b
+        repe cmpsb                ; compare ds:si with es:di
+        jz .done
+
+        add di, 0x20
+        and di, -0x20
+        cmp di, [bpb_bytes_per_sector]
+        jnz .next_entry
+
+        mov si, msg_failed
+        call bios_print
+        jmp $
+
+.done:
+        ret
+
 ; -------------------------------------------------------------------------------------------------
 ; Prints a string to the screen
 ; in: si = address of string
@@ -218,12 +202,12 @@ bios_print:
         pop ax
         ret
 
-; ----------------------------------------------------------------------------------------
+; -------------------------------------------------------------------------------------------------
 msg_load db 'Booting...', 13, 10, 0
 msg_failed db 'Read Failure', 13, 10, 0
-filename_loader db 'LOADER  BIN'
+filename db 'LOADER  BIN'
 
-; ----------------------------------------------------------------------------------------
+; -------------------------------------------------------------------------------------------------
 ; Footer
 times 510-($-$$) db 0    ; Fill boot sector
 dw 0xAA55                ; Boot loader signature
diff --git a/boot/defines.asm b/boot/defines.asm
@@ -0,0 +1,37 @@
+; -------------------------------------------------------------------------------------------------
+; defines.asm
+; -------------------------------------------------------------------------------------------------
+
+; Memory Locations
+%define vm_pml4                     0x2000
+%define vm_pdp                      0x3000
+%define vm_pd                       0x4000
+%define boot_sector_base            0x7c00
+%define temp_sector                 0x7e00
+%define loader_base                 0x8000
+
+%define kernel_stack                0x8000
+%define kernel_base                 0x100000
+
+; Bios Parameter Block
+%define bpb_oem                     boot_sector_base + 0x03
+%define bpb_bytes_per_sector        boot_sector_base + 0x0b
+%define bpb_sectors_per_cluster     boot_sector_base + 0x0d
+%define bpb_reserved_sector_count   boot_sector_base + 0x0e
+%define bpb_fat_count               boot_sector_base + 0x10
+%define bpb_root_entry_count        boot_sector_base + 0x11
+%define bpb_sector_count            boot_sector_base + 0x13
+%define bpb_media_type              boot_sector_base + 0x15
+%define bpb_sectors_per_fat         boot_sector_base + 0x16
+%define bpb_sectors_per_track       boot_sector_base + 0x18
+%define bpb_head_count              boot_sector_base + 0x1a
+%define bpb_hidden_sector_count     boot_sector_base + 0x1c
+%define bpb_large_sector_count      boot_sector_base + 0x20
+
+; Extended Bios Parameter Block
+%define ebpb_drive_number           boot_sector_base + 0x24
+%define epbp_flags                  boot_sector_base + 0x25
+%define epbp_signature              boot_sector_base + 0x26
+%define epbp_volume_id              boot_sector_base + 0x27
+%define epbp_volume_label           boot_sector_base + 0x2b
+%define epbp_filesystem             boot_sector_base + 0x36