0.540s-kernel: write in C.

LINES

@@ -20,3 +20,5 @@
 
 2021-2-25 0.619: 619 lines, 6 files, rain
 
+2021-2-25 0.540: 540 lines, 6 files, rain
+

Makefile

@@ -2,11 +2,17 @@ all:
 	touch boot/x86/bootloader.bin
 	make -C boot/x86/
 	make -C kernel/
+	make cunix.img
 
 clear:
-	rm boot/x86/*.bin kernel/*.bin cunix.img
+	rm *.bin boot/x86/*.bin kernel/*.o kernel/*.bin kernel/init/*.o cunix.img -rf
 
 
 lines:
-	wc boot/x86/boot.asm boot/x86/loader.asm kernel/kernel.asm include/arch/x86/* -l
+	wc boot/x86/boot.asm boot/x86/loader.asm kernel/init/*.c include/arch/x86/* -l
 
+
+cunix.img: boot/x86/bootloader.bin kernel/kernel.bin
+	dd if=/dev/zero of=cunix.img bs=1024 count=1440
+	cat boot/x86/bootloader.bin kernel/kernel.bin > boot.bin
+	dd if=boot.bin of=cunix.img conv=notrunc

README.md

@@ -49,3 +49,5 @@ Cunix kernel
 `0.619s-boot`: 
 &nbsp;&nbsp;&nbsp;&nbsp;load 180KB of disk, not 4KB <br/>
 
+`0.540s-kernel`:
+&nbsp;&nbsp;&nbsp;&nbsp;write in C. <br/>

boot/x86/loader.asm

@@ -28,37 +28,18 @@ jmp _start
 bits 16
 
 _start:	
-	mov si, message
-	call print
+	call set_vga_mode
 
-; init segment register fs
-.init_fs:
 	; enable A20 address 20 line
 .open_a20:
 	in al, 0x92
 	or al, 0x02
 	out 0x92, al
 
+.to_protect_mode:
 	cli
 	lgdt [gdt32_descriptor]
-	mov eax, cr0
-	or eax, 0x01
-	mov cr0, eax
-	
-	mov ax, data32
-	mov fs, ax
-
-	mov eax, cr0
-	and eax, 11111111111111111111111111111110b
-	mov cr0, eax
-
-	; interrupt is disable
-	
-	; now, FS has addressing out of 1MB like protect-mode. 
-	
 
-.to_protect_mode:
-	; GDT is already load by .init_fs
 
 	mov eax, cr0
 	; set CR0.bit 1 (Protect-mode Enable)
@@ -84,6 +65,13 @@ print:
 .do_ret:
 	ret
 
+set_vga_mode:
+	mov al, 0x13
+	mov ah, 0x00
+	int 0x10
+
+	ret
+
 bits 32
 
 init_protect_mode:
@@ -176,9 +164,6 @@ init_long_mode:
 	mov rsp, 0x0000000000007c00
 
 	jmp 0x8200
-	
-
-message: db "Cunix is loading...", 0x0d, 0x0a, 0x00
 
 gdt32:
 	dd 0x00000000, 0x00000000

kernel/Makefile

-ASM_FLAGS = -I ../include
-
-
 default:
-	make ../cunix.img
+	make kernel.bin
+
+init/main.o: init/main.c
+	make -C init/
 
-kernel.bin: kernel.asm
-	nasm kernel.asm -o kernel.bin $(ASM_FLAGS)
+kernel.o: init/main.o
+	ld -b elf64-x86-64 -o kernel.o init/main.o -T kernel.lds
+	
+kernel.bin: kernel.o
+	objcopy -I elf64-x86-64 -S -R ".eh_frame" -R ".comment" -O binary kernel.o kernel.bin
 
-../cunix.img: kernel.bin 
-	cat ../boot/x86/bootloader.bin kernel.bin >> boot.bin
-	dd if=boot.bin of=../cunix.img
 
 

kernel/init/Makefile

+C_FLAGS = -mcmodel=large -fno-builtin -m64 
+
+all: main.o
+
+%.o: %.c
+	gcc -c $*.c $(C_FLAGS)
+
+

kernel/init/main.c

+void init(void) {
+	unsigned long i;
+
+	for (i = 0xa0000; i < 0xaffff; i++) {
+		*((char *) i) = 0x0f;
+	}
+
+	for (;;);
+}

kernel/kernel.asm

-; Copyright (C) 2021 Rain
-
-; This file is part of Cunix. 
-; Cunix is free software: you can redistribute it and/or modify 
-; it under the terms of the GNU General Public License as published by 
-; the Free Software Foundation, either version 3 of the License, or 
-; (at your option) and later version. 
-
-; Cunix is distributed in the hope that it will be useful, 
-; but WITHOUT ANY WARRANTY; without even the implied warranty of 
-; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
-; GNU General Public License for more details. 
-
-; You should have received a copy of the GNU General Public License 
-; along with Cunix. If not, see <https://www.gnu.org/licenses/>.  
-
-
-
-
-org 0x8200
-
-bits 64
-
-_start:
-	mov byte [0xb8000], 'K'
-
-	call setup_idt
-	lidt [idt64_descriptor]
-
-	sti
-
-	jmp $
-
-
-setup_idt:
-	lea rdx, ignore_int
-	mov rax, (0x08 << 16)
-	mov ax, dx
-	mov rcx, (0x8e00 << 32)
-	add rax, rcx
-	mov ecx, edx
-	shr ecx, 16
-	shl rcx, 48
-	add rax, rcx
-	shr rdx, 32
-
-	; we save IDT at 0x0000000000000000 like BIOS
-	lea rdi, 0x0000000000000000
-	mov rcx, 256
-
-.setup_loop:
-	mov [rdi], rax
-	mov [rdi + 8], rdx
-	add rdi, 0x10
-	dec rcx
-	jne .setup_loop
-
-	ret
-
-
-ignore_int:
-	add byte [0xb8000], 1
-
-	; CPU will cli when it call ignore_int
-	hlt
-
-
-idt64_length equ 0xff * 16
-
-idt64_descriptor:
-	dw idt64_length
-	dd 0x0000000000000000
-

kernel/kernel.lds

+OUTPUT_FORMAT("elf64-x86-64","elf64-x86-64", "elf64-x86-64")
+OUTPUT_ARCH(i386:x86-64)
+ENTRY(init)
+
+SECTIONS {
+	. = 0x0000 + 0x8200;
+	.text : {
+		_text = .;
+		*(.text)
+		_etext = .;
+	}
+
+	. = ALIGN(8);
+	.data : {
+		_data = .;
+		*(.data);
+		_edata = .;
+	}
+
+	.rodata : {
+		_rodata = .;
+		*(.rodata)
+		.erodata = .;
+	}
+
+	.bss : {
+		_bss = .;
+		*(.bss)
+		_ebss = .;
+	}
+
+	_end = .;
+}