So I figured that grub2 can do some fancy stuff about loading modules.

There we go! We will keep x86 and load x64 as a module and then jump to x64 from x86!!

legacy_x86/makefile

@@ -1,55 +0,0 @@
-ASM = nasm
-CC = gcc
-LD = ld
-C_SRC_PATH = x86/src/c
-ASM_SRC_PATH = x86/src/asm
-OUTPUT_DIR = temp
-C_FLAGS_32 = -m32 -c -fno-builtin -masm=intel -Wall -Wextra
-ASM_FLAGS_32 = -f elf32 -I $(ASM_SRC_PATH)/
-LD_FLAGS_32 = -m elf_i386
-LD_SCRIPT = build/link.ld
-GRUB_CFG = build/grub.cfg
-
-#C source code
-C_FILES = $(wildcard $(C_SRC_PATH)/*.c)
-
-#ASM source code
-ASM_FILES = $(wildcard $(ASM_SRC_PATH)/*.asm)
-
-#bin files
-KERNEL_BIN = $(OUTPUT_DIR)/kernel.bin
-
-#Object files
-C_OBJ_FILES = $(addprefix $(OUTPUT_DIR)/,$(notdir $(C_FILES:.c=.oc)))
-ASM_OBJ_FILES = $(addprefix $(OUTPUT_DIR)/,$(notdir $(ASM_FILES:.asm=.oasm)))
-ALL_OBJ_FILES = $(C_OBJ_FILES) $(ASM_OBJ_FILES)
-
-
-all : init compile link buildiso clean
-
-init:
-	sudo mkdir $(OUTPUT_DIR)
-
-compile: $(C_OBJ_FILES) $(ASM_OBJ_FILES)
-
-link: $(KERNEL_BIN)	
-
-clean:
-	sudo rm -rf $(OUTPUT_DIR)
-buildiso:
-	sudo mkdir $(OUTPUT_DIR)/temp_iso
-	sudo mkdir $(OUTPUT_DIR)/temp_iso/HOS
-	sudo mkdir $(OUTPUT_DIR)/temp_iso/boot
-	sudo mkdir $(OUTPUT_DIR)/temp_iso/boot/grub
-	sudo mv $(KERNEL_BIN) $(OUTPUT_DIR)/temp_iso/HOS/kernel.bin
-	sudo cp $(GRUB_CFG) $(OUTPUT_DIR)/temp_iso/boot/grub/
-	sudo grub-mkrescue -o HOS.iso $(OUTPUT_DIR)/temp_iso
-
-$(OUTPUT_DIR)/%.oc : $(C_SRC_PATH)/%.c
-	sudo $(CC) $(C_FLAGS_32) -o $@ $^
-
-$(OUTPUT_DIR)/%.oasm : $(ASM_SRC_PATH)/%.asm
-	sudo $(ASM) $(ASM_FLAGS_32) -o $@ $^
-
-$(KERNEL_BIN): $(ALL_OBJ_FILES)
-	sudo $(LD) $(LD_FLAGS_32) -T $(LD_SCRIPT) -o $(KERNEL_BIN) $(ALL_OBJ_FILES)

makefile

@@ -1,38 +1,52 @@
 ASM = nasm
 CC = gcc
 LD = ld
-C_SRC_PATH = x64/src/c
-ASM_SRC_PATH = x64/src/asm
-OUTPUT_DIR = temp
-C_FLAGS = -m64 -c -fno-builtin -mno-red-zone -mno-mmx -mno-sse -mno-sse2 -masm=intel -Wall -Wextra
-ASM_FLAGS = -f elf64 -I $(ASM_SRC_PATH)/
-LD_FLAGS = -melf_x86_64
-LD_SCRIPT = build/link.ld
+#x86 vars
+C_SRC_PATH_32 = x86/src/c
+ASM_SRC_PATH_32 = x86/src/asm
+C_FLAGS_32 = -m32 -c -fno-builtin -mno-red-zone -mno-mmx -mno-sse -mno-sse2 -masm=intel -Wall -Wextra
+ASM_FLAGS_32 = -f elf32 -I $(ASM_SRC_PATH_32)/
+LD_FLAGS_32 = -melf_i386
+LD_SCRIPT_32 = build/link32.ld
+#x64 vars
+C_SRC_PATH_64 = x64/src/c
+ASM_SRC_PATH_64 = x64/src/asm
+C_FLAGS_64 = -m64 -c -fno-builtin -mno-red-zone -mno-mmx -mno-sse -mno-sse2 -masm=intel -Wall -Wextra
+ASM_FLAGS_64 = -f elf64 -I $(ASM_SRC_PATH_64)/
+LD_FLAGS_64 = -melf_x86_64
+LD_SCRIPT_64 = build/link64.ld
+
 GRUB_CFG = build/grub.cfg
+OUTPUT_DIR = temp
 
 #C source code
-C_FILES = $(wildcard $(C_SRC_PATH)/*.c)
+C_FILES_32 = $(wildcard $(C_SRC_PATH_32)/*.c)
+C_FILES_64 = $(wildcard $(C_SRC_PATH_64)/*.c)
 
 #ASM source code
-ASM_FILES = $(wildcard $(ASM_SRC_PATH)/*.asm)
-
+ASM_FILES_32 = $(wildcard $(ASM_SRC_PATH_32)/*.asm)
+ASM_FILES_64 = $(wildcard $(ASM_SRC_PATH_64)/*.asm)
 #bin files
-KERNEL_BIN = $(OUTPUT_DIR)/kernel.bin
+KERNEL_BIN_32 = $(OUTPUT_DIR)/kernel32.bin
+KERNEL_BIN_64 = $(OUTPUT_DIR)/kernel64.bin
+#modules
 
 #Object files
-C_OBJ_FILES = $(addprefix $(OUTPUT_DIR)/,$(notdir $(C_FILES:.c=.oc)))
-ASM_OBJ_FILES = $(addprefix $(OUTPUT_DIR)/,$(notdir $(ASM_FILES:.asm=.oasm)))
-ALL_OBJ_FILES = $(C_OBJ_FILES) $(ASM_OBJ_FILES)
-
+C_OBJ_FILES_32 = $(addprefix $(OUTPUT_DIR)/,$(notdir $(C_FILES_32:.c=_x86.o)))
+C_OBJ_FILES_64 = $(addprefix $(OUTPUT_DIR)/,$(notdir $(C_FILES_64:.c=_x86_64.o)))
+ASM_OBJ_FILES_32 = $(addprefix $(OUTPUT_DIR)/,$(notdir $(ASM_FILES_32:.asm=_asm_x86.o)))
+ASM_OBJ_FILES_64 = $(addprefix $(OUTPUT_DIR)/,$(notdir $(ASM_FILES_64:.asm=_asm_x86_64.o)))
+ALL_OBJ_FILES_32 = $(C_OBJ_FILES_32) $(ASM_OBJ_FILES_32)
+ALL_OBJ_FILES_64 = $(C_OBJ_FILES_64) $(ASM_OBJ_FILES_64)
 
 all : init compile link buildiso clean
 
 init:
 	sudo mkdir $(OUTPUT_DIR)
 
-compile: $(C_OBJ_FILES) $(ASM_OBJ_FILES)
+compile: $(C_OBJ_FILES_32) $(ASM_OBJ_FILES_32) $(C_OBJ_FILES_64) $(ASM_OBJ_FILES_64)
 
-link: $(KERNEL_BIN)	
+link: $(KERNEL_BIN_32) $(KERNEL_BIN_64)
 
 clean:
 	sudo rm -rf $(OUTPUT_DIR)
@@ -41,15 +55,26 @@ buildiso:
 	sudo mkdir $(OUTPUT_DIR)/temp_iso/HOS
 	sudo mkdir $(OUTPUT_DIR)/temp_iso/boot
 	sudo mkdir $(OUTPUT_DIR)/temp_iso/boot/grub
-	sudo mv $(KERNEL_BIN) $(OUTPUT_DIR)/temp_iso/HOS/kernel.bin
+	sudo mkdir $(OUTPUT_DIR)/temp_mod
+	sudo mv $(KERNEL_BIN_64) $(OUTPUT_DIR)/temp_mod/kernel64.mod
+	sudo mv $(KERNEL_BIN_32) $(OUTPUT_DIR)/temp_iso/HOS/kernel32.bin
 	sudo cp $(GRUB_CFG) $(OUTPUT_DIR)/temp_iso/boot/grub/
-	sudo grub-mkrescue -o HOS.iso $(OUTPUT_DIR)/temp_iso
+	sudo grub-mkrescue --modules="$(OUTPUT_DIR)/temp_mod/kernel64" -o HOS.iso $(OUTPUT_DIR)/temp_iso
 
-$(OUTPUT_DIR)/%.oc : $(C_SRC_PATH)/%.c
-	sudo $(CC) $(C_FLAGS) -o $@ $^
+$(OUTPUT_DIR)/%_x86.o: $(C_SRC_PATH_32)/%.c
+	sudo $(CC) $(C_FLAGS_32) -o $@ $^
 
-$(OUTPUT_DIR)/%.oasm : $(ASM_SRC_PATH)/%.asm
-	sudo $(ASM) $(ASM_FLAGS) -o $@ $^
+$(OUTPUT_DIR)/%_x86_64.o: $(C_SRC_PATH_64)/%.c
+	sudo $(CC) $(C_FLAGS_64) -o $@ $^
 
-$(KERNEL_BIN): $(ALL_OBJ_FILES)
-	sudo $(LD) $(LD_FLAGS) -T $(LD_SCRIPT) -o $(KERNEL_BIN) $(ALL_OBJ_FILES)
+$(OUTPUT_DIR)/%_asm_x86.o: $(ASM_SRC_PATH_32)/%.asm
+	sudo $(ASM) $(ASM_FLAGS_32) -o $@ $^
+
+$(OUTPUT_DIR)/%_asm_x86_64.o: $(ASM_SRC_PATH_64)/%.asm
+	sudo $(ASM) $(ASM_FLAGS_64) -o $@ $^
+
+$(KERNEL_BIN_32): $(ALL_OBJ_FILES_32)
+	sudo $(LD) $(LD_FLAGS_32) -T $(LD_SCRIPT_32) -o $(KERNEL_BIN_32) $(ALL_OBJ_FILES_32)
+
+$(KERNEL_BIN_64): $(ALL_OBJ_FILES_64)
+	sudo $(LD) $(LD_FLAGS_64) -T $(LD_SCRIPT_64) -o $(KERNEL_BIN_64) $(ALL_OBJ_FILES_64)

x64/src/asm/entry.asm

@@ -0,0 +1,4 @@
+extern hk_main
+[SECTION .text]
+[BITS 64]
+call hk_main

x64/src/c/entry.c

@@ -0,0 +1,11 @@
+#include "type.h"
+#include "kdef.h"
+
+extern word *kernel_stack;
+
+int64 HYPKERNEL64 hk_main(void)
+{
+    //Setup x64
+    x64:
+    goto x64;
+}

x64/src/c/kdef.h

@@ -0,0 +1,10 @@
+#ifndef _HKDEF32_H_
+#define _HKDEF32_H_
+
+#define HYPKERNEL64
+
+#define BOCHS_MAGIC_BREAKPOINT asm("xchg bx,bx");
+
+#define NULL ((void*)0)
+
+#endif

x86/src/asm/mem32.asm

@@ -18,7 +18,7 @@ mov eax,[ss:ebp+12]
 push eax
 push dword .reload
 retf
-.reload
+.reload:
 mov eax,[ss:ebp+16]
 mov ss,ax
 mov es,ax
@@ -56,9 +56,9 @@ test edx, 1 << 29      ; Test if the LM-bit, which is bit 29, is set in the D-re
 jz .not_supported      ; They aren't, there is no long mode.
 mov eax,1
 jmp .end
-.not_supported
+.not_supported:
 xor eax,eax
-.end
+.end:
 mov esp,ebp
 pop ebp
 ret
@@ -76,4 +76,4 @@ hk_enable_paging:
 mov eax, cr0                                   ; Set the A-register to control register 0.
 or eax, 1 << 31                                ; Set the PG-bit, which is bit 31.
 mov cr0, eax                                   ; Set control register 0 to the A-register.
-ret
+ret

x86/src/c/type32.h

@@ -0,0 +1,15 @@
+#ifndef _TYPE_H_
+#define _TYPE_H_
+typedef unsigned int uint32;
+typedef unsigned short uint16;
+typedef unsigned long long uint64;
+typedef unsigned char uint8;
+typedef int int32;
+typedef short int16;
+typedef long long int64;
+typedef char int8;
+typedef uint8 byte;
+typedef uint16 word;
+typedef uint32 dword;
+typedef uint64 qword;
+#endif