mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-11-27 12:15:19 +01:00
484 lines
9.3 KiB
NASM
484 lines
9.3 KiB
NASM
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DEFAULT_HANDLER_SIZE: equ 9 ; size of exception/interrupt stub
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SYS_CODE_SEL64: equ 0x38 ; 64-bit code selector in GDT
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PE_OFFSET_IN_MZ_STUB: equ 0x3c ; place in MsDos stub for offset to PE Header
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VGA_FB: equ 0x000b8000 ; VGA framebuffer for 80x25 mono mode
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VGA_LINE: equ 80 * 2 ; # bytes in one line
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BASE_ADDR_64: equ 0x00021000
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STACK_TOP: equ 0x001fffe8
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SIZE: equ 0x1000
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struc EFILDR_IMAGE
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.CheckSum: resd 1
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.Offset: resd 1
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.Length: resd 1
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.FileName: resb 52
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endstruc
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struc EFILDR_HEADER
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.Signature: resd 1
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.HeaderCheckSum: resd 1
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.FileLength: resd 1
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.NumberOfImages: resd 1
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endstruc
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struc PE_HEADER
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resb 6
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.NumberOfSections: resw 1
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resb 12
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.SizeOfOptionalHeader: resw 1
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resb 2
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.Magic: resb 16
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.AddressOfEntryPoint: resd 1
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resb 4
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.ImageBase64: resd 1
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endstruc
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struc PE_SECTION_HEADER
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resb 12
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.VirtualAddress: resd 1
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.SizeOfRawData: resd 1
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.PointerToRawData: resd 1
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resb 16
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endstruc
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%macro StubWithNoCode 1
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push 0 ; push error code place holder on the stack
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push %1
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jmp strict qword commonIdtEntry
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%endmacro
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%macro StubWithACode 1
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times 2 nop
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push %1
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jmp strict qword commonIdtEntry
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%endmacro
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%macro PrintReg 2
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mov esi, %1
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call PrintString
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mov rax, [rbp + %2]
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call PrintQword
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%endmacro
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bits 64
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org BASE_ADDR_64
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global _start
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_start:
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mov esp, STACK_TOP
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;
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; set OSFXSR and OSXMMEXCPT because some code will use XMM registers
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;
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mov rax, cr4
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or rax, 0x600
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mov cr4, rax
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;
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; Populate IDT with meaningful offsets for exception handlers...
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;
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sidt [REL Idtr]
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mov eax, StubTable
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mov ebx, eax ; use bx to copy 15..0 to descriptors
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shr eax, 16 ; use ax to copy 31..16 to descriptors
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; 63..32 of descriptors is 0
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mov ecx, 0x78 ; 78h IDT entries to initialize with unique entry points
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mov edi, [REL Idtr + 2]
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.StubLoop: ; loop through all IDT entries exception handlers and initialize to default handler
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mov [rdi], bx ; write bits 15..0 of offset
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mov word [rdi + 2], SYS_CODE_SEL64 ; SYS_CODE_SEL64 from GDT
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mov word [rdi + 4], 0x8e00 ; type = 386 interrupt gate, present
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mov [rdi + 6], ax ; write bits 31..16 of offset
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mov dword [rdi + 8], 0 ; write bits 63..32 of offset
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add edi, 16 ; move up to next descriptor
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add ebx, DEFAULT_HANDLER_SIZE ; move to next entry point
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loop .StubLoop ; loop back through again until all descriptors are initialized
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;
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; Load EFILDR
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;
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mov esi, BlockSignature + 2
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add esi, [rsi + EFILDR_HEADER_size + EFILDR_IMAGE.Offset] ; esi = Base of EFILDR.C
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mov ebp, [rsi + PE_OFFSET_IN_MZ_STUB]
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add ebp, esi ; ebp = PE Image Header for EFILDR.C
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mov edi, [rbp + PE_HEADER.ImageBase64] ; edi = ImageBase (63..32 is zero, ignore)
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mov eax, [rbp + PE_HEADER.AddressOfEntryPoint] ; eax = EntryPoint
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add eax, edi ; eax = ImageBase + EntryPoint
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mov [REL .EfiLdrOffset], eax ; Modify jump instruction for correct entry point
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movzx ebx, word [rbp + PE_HEADER.NumberOfSections] ; bx = Number of sections
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movzx eax, word [rbp + PE_HEADER.SizeOfOptionalHeader]; ax = Optional Header Size
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add ebp, eax
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add ebp, PE_HEADER.Magic ; ebp = Start of 1st Section
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.SectionLoop:
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push rsi ; Save Base of EFILDR.C
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push rdi ; Save ImageBase
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add esi, [rbp + PE_SECTION_HEADER.PointerToRawData] ; esi = Base of EFILDR.C + PointerToRawData
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add edi, [rbp + PE_SECTION_HEADER.VirtualAddress] ; edi = ImageBase + VirtualAddress
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mov ecx, [rbp + PE_SECTION_HEADER.SizeOfRawData] ; ecx = SizeOfRawData
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cld
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shr ecx, 2
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rep movsd
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pop rdi ; Restore ImageBase
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pop rsi ; Restore Base of EFILDR.C
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add ebp, PE_SECTION_HEADER_size ; ebp = Pointer to next section record
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dec ebx
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jnz .SectionLoop
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movzx ecx, word [REL Idtr] ; get size of IDT
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inc ecx
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add ecx, [REL Idtr + 2] ; add to base of IDT to get location of memory map...
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; argument in RCX
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.EfiLdrOffset: equ $ + 1
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mov eax, 0x00401000
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jmp rax ; jump to entry point
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StubTable:
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%assign i 0
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%rep 8
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StubWithNoCode i
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%assign i i+1
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%endrep
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StubWithACode 8 ; Double Fault
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StubWithNoCode 9
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StubWithACode 10 ; Invalid TSS
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StubWithACode 11 ; Segment Not Present
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StubWithACode 12 ; Stack Fault
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StubWithACode 13 ; GP Fault
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StubWithACode 14 ; Page Fault
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StubWithNoCode 15
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StubWithNoCode 16
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StubWithACode 17 ; Alignment Check
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%assign i 18
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%rep 102
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StubWithNoCode i
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%assign i i+1
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%endrep
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commonIdtEntry:
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push rax
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push rcx
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push rdx
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push rbx
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push rsp
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push rbp
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push rsi
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push rdi
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push r8
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push r9
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push r10
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push r11
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push r12
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push r13
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push r14
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push r15
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mov rbp, rsp
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;
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; At this point the stack looks like this:
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;
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; Calling SS
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; Calling RSP
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; rflags
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; Calling CS
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; Calling RIP
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; Error code or 0
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; Int num or 0ffh for unknown int num
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; rax
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; rcx
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; rdx
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; rbx
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; rsp
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; rbp
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; rsi
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; rdi
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; r8
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; r9
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; r10
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; r11
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; r12
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; r13
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; r14
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; r15 <------- RSP, RBP
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;
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call ClearScreen
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mov esi, String1
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call PrintString
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mov eax, [rbp + 16 * 8] ; move Int number into EAX
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cmp eax, 19
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ja .PrintDefaultString
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mov esi, [rax * 8 + StringTable] ; get offset from StringTable to actual string address
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jmp .PrintTheString
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.PrintDefaultString:
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mov esi, IntUnknownString
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; patch Int number
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mov edx, eax
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call A2C
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mov [rsi + 1], al
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mov eax, edx
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shr eax, 4
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call A2C
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mov [rsi], al
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.PrintTheString:
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call PrintString
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PrintReg String2, 19 * 8 ; CS
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mov byte [rdi], ':'
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add edi, 2
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mov rax, [rbp + 18 * 8] ; RIP
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call PrintQword
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mov esi, String3
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call PrintString
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mov edi, VGA_FB + 2 * VGA_LINE
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PrintReg StringRax, 15 * 8
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PrintReg StringRcx, 14 * 8
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PrintReg StringRdx, 13 * 8
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mov edi, VGA_FB + 3 * VGA_LINE
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PrintReg StringRbx, 12 * 8
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PrintReg StringRsp, 21 * 8
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PrintReg StringRbp, 10 * 8
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mov edi, VGA_FB + 4 * VGA_LINE
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PrintReg StringRsi, 9 * 8
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PrintReg StringRdi, 8 * 8
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PrintReg StringEcode, 17 * 8
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mov edi, VGA_FB + 5 * VGA_LINE
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PrintReg StringR8, 7 * 8
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PrintReg StringR9, 6 * 8
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PrintReg StringR10, 5 * 8
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mov edi, VGA_FB + 6 * VGA_LINE
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PrintReg StringR11, 4 * 8
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PrintReg StringR12, 3 * 8
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PrintReg StringR13, 2 * 8
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mov edi, VGA_FB + 7 * VGA_LINE
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PrintReg StringR14, 8
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PrintReg StringR15, 0
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PrintReg StringSs, 22 * 8
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mov edi, VGA_FB + 8 * VGA_LINE
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PrintReg StringRflags, 20 * 8
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mov edi, VGA_FB + 10 * VGA_LINE
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mov rsi, rbp
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add rsi, 23 * 8 ; stack beyond SS
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mov ecx, 4
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.OuterLoop:
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push rcx
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mov ecx, 4
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mov edx, edi
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.InnerLoop:
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mov rax, [rsi]
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call PrintQword
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add rsi, 8
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mov byte [rdi], ' '
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add edi, 2
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loop .InnerLoop
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pop rcx
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add edx, VGA_LINE
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mov edi, edx
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loop .OuterLoop
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mov edi, VGA_FB + 15 * VGA_LINE
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mov rsi, [rbp + 18 * 8] ; RIP
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sub rsi, 8 * 8 ; code preceding RIP
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mov ecx, 4
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.OuterLoop1:
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push rcx
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mov ecx, 4
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mov edx, edi
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.InnerLoop1:
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mov rax, [rsi]
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call PrintQword
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add rsi, 8
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mov byte [rdi], ' '
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add edi, 2
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loop .InnerLoop1
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pop rcx
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add edx, VGA_LINE
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mov edi, edx
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loop .OuterLoop1
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.Halt:
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hlt
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jmp .Halt
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;
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; Return
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;
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mov rsp, rbp
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pop r15
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pop r14
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pop r13
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pop r12
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pop r11
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pop r10
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pop r9
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pop r8
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pop rdi
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pop rsi
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pop rbp
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pop rax ; rsp
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pop rbx
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pop rdx
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pop rcx
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pop rax
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add rsp, 16 ; error code and INT number
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iretq
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PrintString:
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push rax
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.loop:
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mov al, [rsi]
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test al, al
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jz .done
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mov [rdi], al
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inc esi
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add edi, 2
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jmp .loop
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.done:
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pop rax
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ret
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; RAX contains qword to print
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; RDI contains memory location (screen location) to print it to
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PrintQword:
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push rcx
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push rbx
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push rax
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mov ecx, 16
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.looptop:
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rol rax, 4
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mov bl, al
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and bl, 15
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add bl, '0'
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cmp bl, '9'
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jbe .is_digit
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add bl, 7
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.is_digit:
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mov [rdi], bl
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add edi, 2
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loop .looptop
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pop rax
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pop rbx
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pop rcx
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ret
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ClearScreen:
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push rax
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push rcx
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mov ax, 0x0c20
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mov edi, VGA_FB
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mov ecx, 80 * 25
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rep stosw
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mov edi, VGA_FB
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pop rcx
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pop rax
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ret
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A2C:
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and al, 15
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add al, '0'
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cmp al, '9'
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jbe .is_digit
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add al, 7
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.is_digit:
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ret
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String1: db '*** INT ', 0
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Int0String: db '00h Divide by 0 -', 0
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Int1String: db '01h Debug exception -', 0
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Int2String: db '02h NMI -', 0
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Int3String: db '03h Breakpoint -', 0
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Int4String: db '04h Overflow -', 0
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Int5String: db '05h Bound -', 0
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Int6String: db '06h Invalid opcode -', 0
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Int7String: db '07h Device not available -', 0
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Int8String: db '08h Double fault -', 0
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Int9String: db '09h Coprocessor seg overrun (reserved) -', 0
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Int10String: db '0Ah Invalid TSS -', 0
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Int11String: db '0Bh Segment not present -', 0
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Int12String: db '0Ch Stack fault -', 0
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Int13String: db '0Dh General protection fault -', 0
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Int14String: db '0Eh Page fault -', 0
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Int15String: db '0Fh (Intel reserved) -', 0
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Int16String: db '10h Floating point error -', 0
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Int17String: db '11h Alignment check -', 0
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Int18String: db '12h Machine check -', 0
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Int19String: db '13h SIMD Floating-Point Exception -', 0
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IntUnknownString: db '??h Unknown interrupt -', 0
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align 8, db 0
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StringTable:
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%assign i 0
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%rep 20
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dq Int%[i]String
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%assign i i+1
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%endrep
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String2: db ' HALT!! *** (', 0
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String3: db ')', 0
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StringRax: db 'RAX=', 0
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StringRcx: db ' RCX=', 0
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StringRdx: db ' RDX=', 0
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StringRbx: db 'RBX=', 0
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StringRsp: db ' RSP=', 0
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StringRbp: db ' RBP=', 0
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StringRsi: db 'RSI=', 0
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StringRdi: db ' RDI=', 0
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StringEcode: db ' ECODE=', 0
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StringR8: db 'R8 =', 0
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StringR9: db ' R9 =', 0
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StringR10: db ' R10=', 0
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StringR11: db 'R11=', 0
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StringR12: db ' R12=', 0
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StringR13: db ' R13=', 0
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StringR14: db 'R14=', 0
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StringR15: db ' R15=', 0
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StringSs: db ' SS =', 0
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StringRflags: db 'RFLAGS=', 0
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align 2, db 0
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Idtr:
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times SIZE - 2 - $ + $$ db 0
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BlockSignature:
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dw 0xaa55
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