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        disablePaging();

        cout<<"Setup 64 bit paging\n";
        setupPaging64();
        cout<<"Paging setup completed - not enabled\n";

        enablePAE();
        cout<<"PAE enabled\n";

        switchIA32e();
        cout<<"IA32 compatibltiy mode enabled\n";

        enablePaging64();
        cout<<"Paging enabled\n";

        gdt64[0].set(0x0);
        gdt64[1].set(0x0, 0xFFFFFFFF, 0x9A);
        gdt64[2].set(0x0, 0xFFFFFFFF, 0x92);

        if(gdt64[1].isLongMode() && gdt64[2].isLongMode()) {
            cout<<"long mode set\n";
        }

        GDTDescriptor gdtDescriptor64(GDT_ENTRIES_NUM, &gdt64[0]);

        cout<<"Loader finished, entering 64 bit kernel\n";
        enter64BitKernel(&gdtDescriptor64, kernelEntry);

        cout<<"We never should have reached this\n";

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.global setupPaging64
.type setupPaging64, @function
setupPaging64:
        movl $0x1000, %edi
        movl %edi, %cr3
	xorl %eax, %eax
	movl $4096, %ecx
	rep stosl
	movl %cr3, %edi
	
	movl $0x2003, (%edi)
	addl $0x1000, %edi
	movl $0x3003, (%edi)
	addl $0x1000, %edi
	movl $0x4003, (%edi)
	addl $0x1000, %edi

	movl $0x00000003, %ebx
	movl $512, %ecx

.SetEntry:
	movl %ebx, (%edi)
	addl $0x1000, %ebx
	addl $8, %edi
	loop .SetEntry

	ret

.global enablePAE
.type enablePAE, @function
enablePAE:
	movl %cr4, %eax
	orl $0x20, %eax # 1 << 5
	movl %eax, %cr4
	ret

.global switchIA32e
.type switchIA32e, @function
switchIA32e:
	movl $0xC0000080, %ecx
	rdmsr
	orl $0x100, %eax # 1 << 8
	wrmsr
	ret

.global enablePaging64
.type enablePaging64, @function
enablePaging64:
	movl %cr0, %eax
	orl $0x80000000, %eax # 1<<31
	movl %eax, %cr0
	ret

.global enter64BitKernel
.type enter64BitKernel, @function
enter64BitKernel:
	movl 8(%esp), %eax
	movl %eax, (kernel_entry)

	movl 4(%esp), %eax
	lgdt (%eax)

reloadSegmentsLong:			# jump to code segement
        jmp $0x08, $.reloadCSLong
.reloadCSLong:
	mov $0x10, %ax			# load data segment
	mov %ax, %ds
	mov %ax, %es
	mov %ax, %fs
	mov %ax, %gs
	mov %ax, %ss

	movl (kernel_entry), %eax
	#movl $stack_top, %esp
	#.long 0
	jmp *%eax			# jump to new kernel

	ret

Code: Select all

.section .text
.global _start64
.type _start64, @function
_start64:
        movl $0x00b8000, %edi
        movq $500, %rcx
        movq $0x1F201F201F201F20, %rax
        rep stosq
        movl $0x00b8000, %edi
    
# if I uncomment those lines it tripple faults

        #movq $0x1F6C1F6C1F651F48, %rax
        #movq %rax, (%edi)

        #movq $0x1F6F1F571F201F6F, %rax
        #movq %rax, 8(%edi)

        #movq $0x1F211F641F6C1F72, %rax
        #movq %rax, 16(%edi)

        call halt
    
.global halt
.type halt, @function
halt:
         cli
1:
         hlt
         jmp 1b