;------------------------------------------------------------------------------
;*
;* Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
;* This program and the accompanying materials
;* are licensed and made available under the terms and conditions of the BSD License
;* which accompanies this distribution. The full text of the license may be found at
;* http://opensource.org/licenses/bsd-license.php
;*
;* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
;* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;*
;* efi32.asm
;*
;* Abstract:
;*
;------------------------------------------------------------------------------
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Now in 32-bit protected mode.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.486
.model flat
.stack
.code
org 21000h
DEFAULT_HANDLER_SIZE EQU INT1 - INT0
JmpCommonIdtEntry macro
; jmp commonIdtEntry - this must be hand coded to keep the assembler from
; using a 8 bit reletive jump when the entries are
; within 255 bytes of the common entry. This must
; be done to maintain the consistency of the size
; of entry points...
db 0e9h ; jmp 16 bit relative
dd commonIdtEntry - $ - 4 ; offset to jump to
endm
Start:
mov ax,bx ; flat data descriptor in BX
mov ds,ax
mov es,ax
mov fs,ax
mov gs,ax
mov ss,ax
mov esp,0001ffff0h
call ClearScreen
; Populate IDT with meaningful offsets for exception handlers...
sidt fword ptr [Idtr] ; get fword address of IDT
mov eax, offset Halt
mov ebx, eax ; use bx to copy 15..0 to descriptors
shr eax, 16 ; use ax to copy 31..16 to descriptors
mov ecx, 78h ; 78h IDT entries to initialize with unique entry points (exceptions)
mov esi, [offset Idtr + 2]
mov edi, [esi]
@@: ; loop through all IDT entries exception handlers and initialize to default handler
mov word ptr [edi], bx ; write bits 15..0 of offset
mov word ptr [edi+2], 20h ; SYS_CODE_SEL from GDT
mov word ptr [edi+4], 0e00h OR 8000h ; type = 386 interrupt gate, present
mov word ptr [edi+6], ax ; write bits 31..16 of offset
add edi, 8 ; move up to next descriptor
add bx, DEFAULT_HANDLER_SIZE ; move to next entry point
loop @b ; loop back through again until all descriptors are initialized
;; at this point edi contains the offset of the descriptor for INT 20
;; and bx contains the low 16 bits of the offset of the default handler
;; so initialize all the rest of the descriptors with these two values...
; mov ecx, 101 ; there are 100 descriptors left (INT 20 (14h) - INT 119 (77h)
;@@: ; loop through all IDT entries exception handlers and initialize to default handler
; mov word ptr [edi], bx ; write bits 15..0 of offset
; mov word ptr [edi+2], 20h ; SYS_CODE_SEL from GDT
; mov word ptr [edi+4], 0e00h OR 8000h ; type = 386 interrupt gate, present
; mov word ptr [edi+6], ax ; write bits 31..16 of offset
; add edi, 8 ; move up to next descriptor
; loop @b ; loop back through again until all descriptors are initialized
;; DUMP location of IDT and several of the descriptors
; mov ecx, 8
; mov eax, [offset Idtr + 2]
; mov eax, [eax]
; mov edi, 0b8000h
; call PrintDword
; mov esi, eax
; mov edi, 0b80a0h
; jmp OuterLoop
;;
;; just for fun, let's do a software interrupt to see if we correctly land in the exception handler...
; mov eax, 011111111h
; mov ebx, 022222222h
; mov ecx, 033333333h
; mov edx, 044444444h
; mov ebp, 055555555h
; mov esi, 066666666h
; mov edi, 077777777h
; push 011111111h
; push 022222222h
; push 033333333h
; int 119
mov esi,022000h ; esi = 22000
mov eax,[esi+014h] ; eax = [22014]
add esi,eax ; esi = 22000 + [22014] = Base of EFILDR.C
mov ebp,[esi+03ch] ; ebp = [22000 + [22014] + 3c] = NT Image Header for EFILDR.C
add ebp,esi
mov edi,[ebp+034h] ; edi = [[22000 + [22014] + 3c] + 30] = ImageBase
mov eax,[ebp+028h] ; eax = [[22000 + [22014] + 3c] + 24] = EntryPoint
add eax,edi ; eax = ImageBase + EntryPoint
mov dword ptr [EfiLdrOffset],eax ; Modify far jump instruction for correct entry point
mov bx,word ptr[ebp+6] ; bx = Number of sections
xor eax,eax
mov ax,word ptr[ebp+014h] ; ax = Optional Header Size
add ebp,eax
add ebp,018h ; ebp = Start of 1st Section
SectionLoop:
push esi ; Save Base of EFILDR.C
push edi ; Save ImageBase
add esi,[ebp+014h] ; esi = Base of EFILDR.C + PointerToRawData
add edi,[ebp+00ch] ; edi = ImageBase + VirtualAddress
mov ecx,[ebp+010h] ; ecs = SizeOfRawData
cld
shr ecx,2
rep movsd
pop edi ; Restore ImageBase
pop esi ; Restore Base of EFILDR.C
add bp,028h ; ebp = ebp + 028h = Pointer to next section record
dec bx
cmp bx,0
jne SectionLoop
movzx eax, word ptr [Idtr] ; get size of IDT
inc eax
add eax, dword ptr [Idtr + 2] ; add to base of IDT to get location of memory map...
push eax ; push memory map location on stack for call to EFILDR...
push eax ; push return address (useless, just for stack balance)
db 0b8h
EfiLdrOffset:
dd 000401000h ; Offset of EFILDR
; mov eax, 401000h
push eax
ret
; db "**** DEFAULT IDT ENTRY ***",0
align 02h
Halt:
INT0:
push 0h ; push error code place holder on the stack
push 0h
JmpCommonIdtEntry
; db 0e9h ; jmp 16 bit reletive
; dd commonIdtEntry - $ - 4 ; offset to jump to
INT1:
push 0h ; push error code place holder on the stack
push 1h
JmpCommonIdtEntry
INT2:
push 0h ; push error code place holder on the stack
push 2h
JmpCommonIdtEntry
INT3:
push 0h ; push error code place holder on the stack
push 3h
JmpCommonIdtEntry
INT4:
push 0h ; push error code place holder on the stack
push 4h
JmpCommonIdtEntry
INT5:
push 0h ; push error code place holder on the stack
push 5h
JmpCommonIdtEntry
INT6:
push 0h ; push error code place holder on the stack
push 6h
JmpCommonIdtEntry
INT7:
push 0h ; push error code place holder on the stack
push 7h
JmpCommonIdtEntry
INT8:
; Double fault causes an error code to be pushed so no phony push necessary
nop
nop
push 8h
JmpCommonIdtEntry
INT9:
push 0h ; push error code place holder on the stack
push 9h
JmpCommonIdtEntry
INT10:
; Invalid TSS causes an error code to be pushed so no phony push necessary
nop
nop
push 10
JmpCommonIdtEntry
INT11:
; Segment Not Present causes an error code to be pushed so no phony push necessary
nop
nop
push 11
JmpCommonIdtEntry
INT12:
; Stack fault causes an error code to be pushed so no phony push necessary
nop
nop
push 12
JmpCommonIdtEntry
INT13:
; GP fault causes an error code to be pushed so no phony push necessary
nop
nop
push 13
JmpCommonIdtEntry
INT14:
; Page fault causes an error code to be pushed so no phony push necessary
nop
nop
push 14
JmpCommonIdtEntry
INT15:
push 0h ; push error code place holder on the stack
push 15
JmpCommonIdtEntry
INT16:
push 0h ; push error code place holder on the stack
push 16
JmpCommonIdtEntry
INT17:
; Alignment check causes an error code to be pushed so no phony push necessary
nop
nop
push 17
JmpCommonIdtEntry
INT18:
push 0h ; push error code place holder on the stack
push 18
JmpCommonIdtEntry
INT19:
push 0h ; push error code place holder on the stack
push 19
JmpCommonIdtEntry
INTUnknown:
REPEAT (78h - 20)
push 0h ; push error code place holder on the stack
; push xxh ; push vector number
db 06ah
db ( $ - INTUnknown - 3 ) / 9 + 20 ; vector number
JmpCommonIdtEntry
ENDM
commonIdtEntry:
pushad
mov ebp, esp
;;
;; At this point the stack looks like this:
;;
;; eflags
;; Calling CS
;; Calling EIP
;; Error code or 0
;; Int num or 0ffh for unknown int num
;; eax
;; ecx
;; edx
;; ebx
;; esp
;; ebp
;; esi
;; edi <------- ESP, EBP
;;
call ClearScreen
mov esi, offset String1
call PrintString
mov eax, [ebp + 32] ;; move Int number into EAX
cmp eax, 19
ja PrintDefaultString
PrintExceptionString:
shl eax, 2 ;; multiply by 4 to get offset from StringTable to actual string address
add eax, offset StringTable
mov esi, [eax]
jmp PrintTheString
PrintDefaultString:
mov esi, offset IntUnknownString
; patch Int number
mov edx, eax
call A2C
mov [esi + 1], al
mov eax, edx
shr eax, 4
call A2C
mov [esi], al
PrintTheString:
call PrintString
mov esi, offset String2
call PrintString
mov eax, [ebp+44] ; CS
call PrintDword
mov al, ':'
mov byte ptr [edi], al
add edi, 2
mov eax, [ebp+40] ; EIP
call PrintDword
mov esi, offset String3
call PrintString
mov edi, 0b8140h
mov esi, offset StringEax ; eax
call PrintString
mov eax, [ebp+28]
call PrintDword
mov esi, offset StringEbx ; ebx
call PrintString
mov eax, [ebp+16]
call PrintDword
mov esi, offset StringEcx ; ecx
call PrintString
mov eax, [ebp+24]
call PrintDword
mov esi, offset StringEdx ; edx
call PrintString
mov eax, [ebp+20]
call PrintDword
mov esi, offset StringEcode ; error code
call PrintString
mov eax, [ebp+36]
call PrintDword
mov edi, 0b81e0h
mov esi, offset StringEsp ; esp
call PrintString
mov eax, [ebp+12]
call PrintDword
mov esi, offset StringEbp ; ebp
call PrintString
mov eax, [ebp+8]
call PrintDword
mov esi, offset StringEsi ; esi
call PrintString
mov eax, [ebp+4]
call PrintDword
mov esi, offset StringEdi ; edi
call PrintString
mov eax, [ebp]
call PrintDword
mov esi, offset StringEflags ; eflags
call PrintString
mov eax, [ebp+48]
call PrintDword
mov edi, 0b8320h
mov esi, ebp
add esi, 52
mov ecx, 8
OuterLoop:
push ecx
mov ecx, 8
mov edx, edi
InnerLoop:
mov eax, [esi]
call PrintDword
add esi, 4
mov al, ' '
mov [edi], al
add edi, 2
loop InnerLoop
pop ecx
add edx, 0a0h
mov edi, edx
loop OuterLoop
mov edi, 0b8960h
mov eax, [ebp+40] ; EIP
sub eax, 32 * 4
mov esi, eax ; esi = eip - 32 DWORD linear (total 64 DWORD)
mov ecx, 8
OuterLoop1:
push ecx
mov ecx, 8
mov edx, edi
InnerLoop1:
mov eax, [esi]
call PrintDword
add esi, 4
mov al, ' '
mov [edi], al
add edi, 2
loop InnerLoop1
pop ecx
add edx, 0a0h
mov edi, edx
loop OuterLoop1
; wbinvd ; Ken: this intruction does not support in early than 486 arch
@@:
jmp @b
;
; return
;
mov esp, ebp
popad
add esp, 8 ; error code and INT number
iretd
PrintString:
push eax
@@:
mov al, byte ptr [esi]
cmp al, 0
je @f
mov byte ptr [edi], al
inc esi
add edi, 2
jmp @b
@@:
pop eax
ret
;; EAX contains dword to print
;; EDI contains memory location (screen location) to print it to
PrintDword:
push ecx
push ebx
push eax
mov ecx, 8
looptop:
rol eax, 4
mov bl, al
and bl, 0fh
add bl, '0'
cmp bl, '9'
jle @f
add bl, 7
@@:
mov byte ptr [edi], bl
add edi, 2
loop looptop
;wbinvd
pop eax
pop ebx
pop ecx
ret
ClearScreen:
push eax
push ecx
mov al, ' '
mov ah, 0ch
mov edi, 0b8000h
mov ecx, 80 * 24
@@:
mov word ptr [edi], ax
add edi, 2
loop @b
mov edi, 0b8000h
pop ecx
pop eax
ret
A2C:
and al, 0fh
add al, '0'
cmp al, '9'
jle @f
add al, 7
@@:
ret
String1 db "*** INT ",0
Int0String db "00h Divide by 0 -",0
Int1String db "01h Debug exception -",0
Int2String db "02h NMI -",0
Int3String db "03h Breakpoint -",0
Int4String db "04h Overflow -",0
Int5String db "05h Bound -",0
Int6String db "06h Invalid opcode -",0
Int7String db "07h Device not available -",0
Int8String db "08h Double fault -",0
Int9String db "09h Coprocessor seg overrun (reserved) -",0
Int10String db "0Ah Invalid TSS -",0
Int11String db "0Bh Segment not present -",0
Int12String db "0Ch Stack fault -",0
Int13String db "0Dh General protection fault -",0
Int14String db "0Eh Page fault -",0
Int15String db "0Fh (Intel reserved) -",0
Int16String db "10h Floating point error -",0
Int17String db "11h Alignment check -",0
Int18String db "12h Machine check -",0
Int19String db "13h SIMD Floating-Point Exception -",0
IntUnknownString db "??h Unknown interrupt -",0
StringTable dd offset Int0String, offset Int1String, offset Int2String, offset Int3String,
offset Int4String, offset Int5String, offset Int6String, offset Int7String,
offset Int8String, offset Int9String, offset Int10String, offset Int11String,
offset Int12String, offset Int13String, offset Int14String, offset Int15String,
offset Int16String, offset Int17String, offset Int18String, offset Int19String
String2 db " HALT!! *** (",0
String3 db ")",0
StringEax db "EAX=",0
StringEbx db " EBX=",0
StringEcx db " ECX=",0
StringEdx db " EDX=",0
StringEcode db " ECODE=",0
StringEsp db "ESP=",0
StringEbp db " EBP=",0
StringEsi db " ESI=",0
StringEdi db " EDI=",0
StringEflags db " EFLAGS=",0
Idtr df 0
org 21ffeh
BlockSignature:
dw 0aa55h
end