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page 78,132;*******************************************************************************; Copyright (c) Microsoft Corporation 1991; All Rights Reserved;; ke\i386\emxcptn.asm;; Module to support getting/setting context to and from the R3; emulator.;;Revision History:;;;*******************************************************************************
.386p_TEXT SEGMENT DWORD PUBLIC 'CODE' ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
;;*******************************************************************************;;;; Include some more macros and constants.;;;;*******************************************************************************;
NT386 equ 1
include ks386.inc include em387.inc ; Emulator TEB data layout include callconv.inc
EXTRNP _KeGetCurrentIrql,0 EXTRNP _KeBugCheck,1 EXTRNP _ExRaiseStatus,1 extrn _Ki387RoundModeTable:dword
subttl _KiEm87StateToNpxFrame page
;*** _KiEm87StateToNpxFrames;; Translates the R3 emulators state to the NpxFrame;; Returns TRUE if NpxFrame sucessfully completed.; else FALSE;; Warning: This function can only be called at Irql 0 with interrupts; enabled. It is intended to be called only to deal with R3 exceptions; when the emulator is being used.;; Revision History:;;;*******************************************************************************
cPublicProc _KiEm87StateToNpxFrame, 1 push ebp mov ebp, esp push ebx ; Save C runtime varibles push edi push esi
push esp ; Pass current Esp to handler push offset stnpx_30 ; Set Handler address push PCR[PcExceptionList] ; Set next pointer mov PCR[PcExceptionList],esp ; Link us on
if DBG pushfd ; Sanity check pop ecx ; make sure interrupts are enabled test ecx, EFLAGS_INTERRUPT_MASK jz short stnpx_err
stdCall _KeGetCurrentIrql ; Sanity check cmp al, DISPATCH_LEVEL ; make sure Irql is below DPC level jnc short stnpx_errendif
xor eax, eax ; set FALSE
mov ebx,PCR[PcPrcbData+PbCurrentThread] mov ebx,[ebx]+ThApcState+AsProcess cmp dword ptr [ebx]+PrVdmObjects,0 ; is this a vdm process? jne short stnpx_10 ; Yes, then not supported
mov ebx, PCR[PcTeb] ; R3 Teb cmp [ebx].Einstall, 0 ; Initialized? je short stnpx_10 ; No, then don't return NpxFrame
test [ebx].CURErr, Summary ; Completed? jz short stnpx_10 ; No, then don't return NpxFrame
mov esi, [ebp+8] ; (esi) = NpxFrame call SaveState
mov eax, 1 ; Return TRUEstnpx_10: pop PCR[PcExceptionList] ; Remove our exception handle add esp, 8 ; clear stack pop esi pop edi pop ebx pop ebp stdRET _KiEm87StateToNpxFrame
stnpx_30:;; WARNING: Here we directly unlink the exception handler from the; exception registration chain. NO unwind is performed. We can take; this short cut because we know that our handler is a leaf-node.;
mov esp, [esp+8] ; (esp)-> ExceptionList xor eax, eax ; Return FALSE jmp short stnpx_10
if DBGstnpx_err: stdCall _KeBugCheck <IRQL_NOT_LESS_OR_EQUAL>endif_KiEm87StateToNpxFrame ENDP
;*** SaveEnv;;; ARGUMENTS;; (esi) = NpxFrame; (ebx) = PcTeb;;; DESCRIPTION;
SaveEnv: xor ax,ax mov [esi].reserved1,ax mov [esi].reserved2,ax mov [esi].reserved3,ax mov [esi].reserved4,ax mov [esi].reserved5,ax mov ax,[ebx].ControlWord mov [esi].E32_ControlWord,ax call GetEMSEGStatusWord mov [esi].E32_StatusWord,ax call GetTagWord mov [esi].E32_TagWord,ax mov ax,cs mov [esi].E32_CodeSeg,ax ; NOTE: Not R0 code & stack mov ax,ss mov [esi].E32_DataSeg,ax mov eax,[ebx].PrevCodeOff mov [esi].E32_CodeOff,eax mov eax,[ebx].PrevDataOff mov [esi].E32_DataOff,eax ret
;*** SaveState -;; ARGUMENTS; (esi) = where to store environment; (ebx) = PcTeb;; DESCRIPTION;; REGISTERS; Destroys ALL, but EBX;
SaveState: ; Enter here for debugger save state mov dword ptr [esi].FpCr0NpxState, CR0_EM
call SaveEnv add esi,size Env80x87_32 ;Skip over environment mov ebp,NumLev ;Save entire stack mov edi,[ebx].CURstkss_loop: mov eax,[ebx+edi].ExpSgn call StoreTempReal ;in emstore.asm add esi,10
mov edi,[ebx].CURstk;;; NextStackElem edi,SaveState cmp edi,INITstk jae short ss_wrap add edi,Reg87Lenss_continue: mov [ebx].CURstk,edi dec ebp jnz short ss_loop retss_wrap: mov edi, BEGstk jmp short ss_continue
;*** GetTagWord - figures out what the tag word is from the numeric stack; and returns the value of the tag word in ax.;; ARGUMENTS; (ebx) = PcTeb;
GetTagWord: push esi xor eax, eax mov ecx, NumLev ; get tags for regs. 0, 7 - 1 mov esi, INITstkGetTagLoop: mov dh, [ebx+esi].bTag ; The top 2 bits of Tag are the X87 tag bits. shld ax, dx, 2 sub esi, Reg87Len loop GetTagLoop rol ax, 2 ; This moves Tag(0) into the low 2 bits pop esi ret
;*** GetEMSEGStatusWord;; User status word returned in ax.; Uses status word in per-thread data area, otherwise; identical to GetStatusWord;; ARGUMENTS; (ebx) = PcTeb
GetEMSEGStatusWord: mov eax, [ebx].CURstk sub eax, BEGstk
; ; Make sure the 'div' won't overflowed. ;
cmp eax, Reg87Len * (NumLev + 2) ja short @f
mov dl,Reg87Len div dl inc eax and eax, 7 ; eax is now the stack number shl ax, 11 or ax, [ebx].StatusWord ; or in the rest of the status word. ret@@: mov eax, STATUS_INTEGER_OVERFLOW stdCall _ExRaiseStatus, <eax> ret ; Should never come here ...
;*** StoreTempReal;;; ARGUMENTS; ??; (ebx) = PcTeb;
StoreTempReal: mov edx,[ebx+edi].lManHi mov edi,[ebx+edi].lManLo;mantissa in edx:edi, exponent in high eax, sign in ah bit 7, tag in al;memory destination is esi mov ecx,eax ;get copy of sign and tag shr ecx,16 ;Bring exponent down cmp al,bTAG_ZERO jz short StoreIEEE80 ;Skip bias if zero add ecx,IexpBias-TexpBias ;Correct bias cmp al,bTAG_DEN jz short Denorm80StoreIEEE80: and eax,bSign shl 8 or ecx,eax ;Combine sign with exponent mov [esi],edi mov [esi+4],edx mov [esi+8],cx ret
Denorm80:;Must change it to a denormal dec ecx neg ecx ;Use as shift count cmp cl,32 ;Long shift? jae LongDenorm shrd edi,edx,cl shr edx,cl xor ecx,ecx ;Exponent is zero jmp short StoreIEEE80
LongDenorm:;edi must be zero if we have 32 bits to shift xchg edx,edi ;32-bit right shift shr edi,cl ;shift count is modulo-32 xor ecx,ecx ;Exponent is zero jmp short StoreIEEE80
;****************************************************;****************************************************;****************************************************;****************************************************
;*** _KiNpxFrameToEm87State;; Translates the NpxFrame to the R3 emulators state;; Returns TRUE if NpxFrame state sucessfully transfered.; else FALSE;; Warning: This function can only be called at Irql 0 with interrupts; enabled. It is intended to be called only to deal with R3 exceptions; when the emulator is being used.;; Revision History:;;;*******************************************************************************
cPublicProc _KiNpxFrameToEm87State, 1 push ebp mov ebp, esp push ebx ; Save C runtime varibles push edi push esi
push esp ; Pass current Esp to handler push offset npxts_30 ; Set Handler address push PCR[PcExceptionList] ; Set next pointer mov PCR[PcExceptionList],esp ; Link us on
if DBG pushfd ; Sanity check pop ecx ; make sure interrupts are enabled test ecx, EFLAGS_INTERRUPT_MASK jz short npxts_err
stdCall _KeGetCurrentIrql ; Sanity check cmp al, DISPATCH_LEVEL ; make sure Irql is below DPC level jnc short npxts_errendif
xor eax, eax ; set FALSE
mov ebx,PCR[PcPrcbData+PbCurrentThread] mov ebx,[ebx]+ThApcState+AsProcess cmp dword ptr [ebx]+PrVdmObjects,0 ; is this a vdm process? jne short npxts_10 ; Yes, then not supported
mov ebx, PCR[PcTeb] ; R3 Teb cmp [ebx].Einstall, 0 ; Initialized? je short npxts_10 ; No, then don't set NpxFrame
mov esi, [ebp+8] ; (esi) = NpxFrame call StorState or [ebx].CURErr, Summary ; Set completed
mov eax, 1 ; Return TRUEnpxts_10: pop PCR[PcExceptionList] ; Remove our exception handle add esp, 8 ; clear stack pop esi pop edi pop ebx pop ebp stdRet _KiNpxFrameToEm87State
npxts_30:;; WARNING: Here we directly unlink the exception handler from the; exception registration chain. NO unwind is performed. We can take; this short cut because we know that our handler is a leaf-node.;
mov esp, [esp+8] ; (esp)-> ExceptionList xor eax, eax ; Return FALSE jmp short npxts_10 ret
if DBGnpxts_err: stdCall _KeBugCheck <IRQL_NOT_LESS_OR_EQUAL>endif_KiNpxFrameToEm87State ENDP
;*** StorState - emulate FRSTOR [address];; ARGUMENTS; (esi) = where to get the environment; (ebx) = PcTeb;;; DESCRIPTION; This routine emulates an 80387 FRSTOR (restore state)
StorState:;First we set up the status word so that [CURstk] is initialized.;The floating-point registers are stored in logical ST(0) - ST(7) order,;not physical register order. We don't do a full load of the environment;because we're not ready to use the tag word yet.
mov ax, [esi].E32_StatusWord call SetEmStatusWord ;Initialize [CURstk] add esi,size Env80x87_32 ;Skip over environment
;Load of temp real has one difference from real math chip: it is an invalid;operation to load an unsupported format. By ensuring the exception is;masked, we will convert unsupported format to Indefinite. Note that the;mask and [CURerr] will be completely restored by the FLDENV at the end.
mov [ebx].CWmask,3FH ;Mask off invalid operation exception mov edi,[ebx].CURstk mov ebp,NumLevFrstorLoadLoop: push esi call LoadTempReal ;In emload.asm pop esi add esi,10 ;Point to next temp real;;; NextStackElem edi,Frstor cmp edi,INITstk jae short fr_wrap add edi,Reg87Lenfr_continue: dec ebp jnz short FrstorLoadLoop sub esi,NumLev*10+size Env80x87_32 ;Point to start of env.;; Stor Enviroment; (esi) = where to get enviroment; (ebx) = PcTeb;
mov ax, [esi].E32_StatusWord call SetEmStatusWord ; set up status word mov ax, [esi].E32_ControlWord call SetControlWord mov ax, [esi].E32_TagWord call UseTagWord
mov eax, [esi].E32_CodeOff mov [ebx].PrevCodeOff, eax mov eax, [esi].E32_DataOff mov [ebx].PrevDataOff, eax ret
fr_wrap: mov edi, BEGstk jmp short fr_continue
;*** SetEmStatusWord -;; Given user status word in ax, set into emulator.; Destroys ebx only.
SetEmStatusWord: and ax,7F7FH mov cx,ax and cx,3FH ; set up CURerr in case user mov [ebx].CURerr,cl ; wants to force an exception mov ecx, eax and ecx, not (7 shl 11) ; remove stack field. mov [ebx].StatusWord, cx
sub ah, 8 ; adjust for emulator's stack layout and ah, 7 shl 3 mov al, ah shr ah, 1 add al, ah ; stack field * 3 * 4.erre Reg87Len eq 12 and eax, 255 ; eax is now 12*stack number add eax, BEGstk mov [ebx].CURstk, eax ret
SetControlWord: and ax,0F3FH ; Limit to valid values mov [ebx].ControlWord, ax ; Store in the emulated control word not al ;Flip mask bits for fast compare and al,3FH ;Limit to valid mask bits mov [ebx].ErrMask,al and eax,(RoundControl + PrecisionControl) shl 8.erre RoundControl eq 1100B.erre PrecisionControl eq 0011B shr eax,6 ;Put PC and RC in bits 2-5 mov ecx,_Ki387RoundModeTable mov ecx,[ecx+eax] ;Get correct RoundMode vector mov [ebx].RoundMode,ecx mov [ebx].SavedRoundMode,ecx and eax,RoundControl shl (8-6) ;Mask off precision control mov ecx,_Ki387RoundModeTable mov ecx,[ecx+(eax+PC64 shl (8-6))];Get correct RoundMode vector mov [ebx].TransRound,ecx ;Round mode w/o precision ret
;*** UseTagWord - Set up tags using tag word from environment;; ARGUMENTS; ax - should contain the tag word;; Destroys ax,bx,cx,dx,di
UseTagWord: ror ax, 2 ; mov Tag(0) into top bits of ax mov edi,INITstk mov ecx, NumLevUseTagLoop: mov dl,bTAG_EMPTY cmp ah, 0c0h ;Is register to be tagged Empty? jae short SetTag ;Yes, go mark it mov dl,[ebx+edi].bTag ;Get current tag cmp dl,bTAG_EMPTY ;Is register currently Empty? je short SetTagNotEmpty ;If so, go figure out tag for itSetTag: mov [ebx+edi].bTag,dlUseTagLoopCheck: sub edi, Reg87Len shl eax, 2 loop UseTagLoop ret
SetTagEmpty: mov [ebx+edi].bTag, bTAG_EMPTY jmp short UseTagLoopCheck
SetTagNotEmpty:;Register is currently tagged empty, but new tag word says it is not empty.;Figure out a new tag for it. The rules are:;;1. Everything is either normalized or zero--unnormalized formats cannot;get in. So if the high half mantissa is zero, the number is zero.;;2. Although the exponent bias is different, NANs and Infinities are in;standard IEEE format - exponent is TexpMax, mantissa indicates NAN vs.;infinity (mantissa for infinity is 800..000H).;;3. Denormals have an exponent less than TexpMin.;;4. If the low half of the mantissa is zero, it is tagged bTAG_SNGL;;5. Everything else is bTAG_VALID
cmp [ebx+edi].lManHi, 0 mov dl,bTAG_ZERO ;Try zero first jz short SetTag ;Is mantissa zero? mov edx,[ebx+edi].ExpSgn mov dl,bTAG_DEN cmp edx,TexpMin shl 16 ;Is it denormal? jl short SetTag cmp [ebx+edi].lManLo,0 ;Is low half zero?.erre bTAG_VALID eq 1.erre bTAG_SNGL eq 0 setnz dl ;if low half==0 then dl=0 else dl=1 cmp edx,TexpMax shl 16 ;Is it NAN or Infinity? jl short SetTag ;If not, it's valid.erre (bTAG_VALID - bTAG_SNGL) shl TAG_SHIFT eq (bTAG_NAN - bTAG_INF) shl dl,TAG_SHIFT add dl,bTAG_INF - bTAG_SNGL;If the low bits were zero we have just changed bTAG_SNGL to bTAG_INF;If the low bits weren't zero, we changed bTAG_VALID to bTAG_NAN;See if infinity is really possible: is high half 80..00H? cmp [ebx+edi].lManHi,1 shl 31 ;Is it infinity? jz short SetTag ;Store tag for infinity or NAN mov dl,bTAG_NAN jmp short SetTag
;*** LoadTempReal;;;
LoadTempReal: mov ebx,[esi+4] ;Get high half of mantissa mov cx,[esi+8] ;Get exponent and sign mov esi,[esi] ;Get low half of mantissa mov eax,ecx and ch,7FH ;Mask off sign bit shl ecx,16 ;Move exponent to high end mov ch,ah ;Restore sign jz short ZeroOrDenorm80;Check for unsupported format: unnormals (MSB not set) or ebx,ebx jns short Unsupported sub ecx,(IexpBias-TexpBias) shl 16 ;Correct the bias cmp ecx,TexpMax shl 16 jge short NANorInf80SetupTag: or esi,esi ;Any bits in low half?.erre bTAG_VALID eq 1.erre bTAG_SNGL eq 0 setnz cl ;if low half==0 then cl=0 else cl=1 jmp short SaveStack
NANorInf80: mov cl,bTAG_NAN cmp ebx,1 shl 31 ;Only 1 bit set means infinity jnz short SaveStack or esi,esi jnz short SaveStack mov cl,bTAG_INF jmp short SaveStack
ZeroOrDenorm80:;Exponent is zero. Number is either zero or denormalized or ebx,ebx jnz short ShortNorm80 ;Are top 32 bits zero? or esi,esi ;Are low 32 bits zero too? jnz LongNorm80 mov cl,bTAG_ZERO jmp short SaveStack
;This code accepts and works correctly with pseudo-denormals (MSB already set)LongNorm80: xchg ebx,esi ;Shift up 32 bits sub ecx,32 shl 16 ;Correct exponentShortNorm80: add ecx,(TexpBias-IexpBias+1-31) shl 16 ;Fix up bias bsr edx,ebx ;Scan for MSB;Bit number in edx ranges from 0 to 31 mov cl,dl not cl ;Convert bit number to shift count shld ebx,esi,cl shl esi,cl shl edx,16 ;Move exp. adjustment to high end add ecx,edx ;Adjust exponent jmp short SetUpTag
SaveStack: mov eax, PCR[PcTeb] mov [eax].CURstk,edi mov [eax+edi].lManLo,esi mov [eax+edi].lManHi,ebx mov [eax+edi].ExpSgn,ecx mov ebx, eax ; (ebx) = PcTeb ret
Unsupported: mov ebx, PCR[PcTeb] or [ebx].CURerr,Invalid ; (assume it's masked?) mov [ebx+edi].lManLo,0 mov [ebx+edi].lManHi,0C0000000H mov [ebx+edi].ExpSgn,TexpMax shl 16 + bSign shl 8 + bTAG_NAN mov [ebx].CURstk,edi ;Update top of stack ret
_TEXT ENDSEND
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