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|
; $Id: fesetenv.asm $
;; @file
; IPRT - No-CRT fesetenv - AMD64 & X86.
;
;
; Copyright (C) 2022 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
%define RT_ASM_WITH_SEH64
%include "iprt/asmdefs.mac"
%include "iprt/x86.mac"
%define RT_NOCRT_FE_DFL_ENV 1
%define RT_NOCRT_FE_NOMASK_ENV 2
%define RT_NOCRT_FE_PC53_ENV 3
%define RT_NOCRT_FE_PC64_ENV 4
%define RT_NOCRT_FE_LAST_ENV 4
BEGINCODE
;;
; Sets the FPU+SSE environment.
;
; @returns eax = 0 on success, -1 on failure.
; @param pEnv 32-bit: [xBP+8] msc64: rcx gcc64: rdi - Saved environment to restore.
;
RT_NOCRT_BEGINPROC fesetenv
push xBP
SEH64_PUSH_xBP
mov xBP, xSP
SEH64_SET_FRAME_xBP 0
sub xBP, 20h
SEH64_ALLOCATE_STACK 20h
SEH64_END_PROLOGUE
;
; Load the parameter into rcx.
;
%ifdef ASM_CALL64_GCC
mov rcx, rdi
%elifdef RT_ARCH_X86
mov ecx, [xBP + xCB*2]
%endif
;
; For the x87 state we only set FSW.XCPT, FCW.XCPT, FCW.RC and FCW.PC.
; So we save the current environment, merge those fields and load it.
;
fnstenv [xBP - 20h]
; Check for special "pointer" values:
cmp xCX, RT_NOCRT_FE_LAST_ENV
ja .x87_regular
or eax, -1
test xCX, xCX
jnz .x87_special
%ifdef RT_STRICT
int3
%endif
jmp .return
;
; Special x87 state. Clear all pending exceptions.
;
; We have 4 special environments with only some differences in FCW differs, so set
; up FCW in AX, starting with a NOMASK environment as it has the fewest bits set.
;
.x87_special:
and word [xBP - 20h + X86FSTENV32P.FSW], ~X86_FSW_XCPT_ES_MASK
mov ax, [xBP - 20h + X86FSTENV32P.FCW]
and ax, ~(X86_FCW_MASK_ALL | X86_FCW_PC_MASK | X86_FCW_RC_MASK | X86_FCW_IC_MASK)
%ifdef RT_OS_WINDOWS
or ax, X86_FCW_DM | X86_FCW_PC_53 | X86_FCW_RC_NEAREST | X86_FCW_IC_PROJECTIVE
%else
or ax, X86_FCW_DM | X86_FCW_PC_64 | X86_FCW_RC_NEAREST | X86_FCW_IC_PROJECTIVE
%endif
cmp xCX, RT_NOCRT_FE_NOMASK_ENV
je .x87_special_done
or ax, X86_FCW_MASK_ALL
%ifdef RT_OS_WINDOWS
cmp xCX, RT_NOCRT_FE_PC64_ENV
jne .x87_special_done
or ax, X86_FCW_PC_64 ; X86_FCW_PC_64 is a super set of X86_FCW_PC_53, so no need to clear bits
%else
cmp xCX, RT_NOCRT_FE_PC53_ENV
jne .x87_special_done
and ax, X86_FCW_PC_64 & ~X86_FCW_PC_53 ; X86_FCW_PC_64 is a super set of X86_FCW_PC_53, so clear the bit that differs.
%endif
.x87_special_done:
mov [xBP - 20h + X86FSTENV32P.FCW], ax
jmp .x87_common
;
; Merge input and current.
;
.x87_regular:
; FCW:
mov ax, [xCX + X86FSTENV32P.FCW]
mov dx, [xBP - 20h + X86FSTENV32P.FCW]
and ax, X86_FCW_MASK_ALL | X86_FCW_RC_MASK | X86_FCW_PC_MASK
and dx, ~(X86_FCW_MASK_ALL | X86_FCW_RC_MASK | X86_FCW_PC_MASK)
or dx, ax
mov [xBP - 20h + X86FSTENV32P.FCW], dx
; FSW
mov ax, [xCX + X86FSTENV32P.FSW]
mov dx, [xBP - 20h + X86FSTENV32P.FSW]
and ax, X86_FSW_XCPT_MASK
and dx, ~(X86_FSW_XCPT_MASK)
or dx, ax
mov [xBP - 20h + X86FSTENV32P.FSW], dx
.x87_common:
; Clear the exception info.
xor eax, eax
mov [xBP - 20h + X86FSTENV32P.FPUIP], eax
mov [xBP - 20h + X86FSTENV32P.FPUCS], eax ; covers FOP too.
mov [xBP - 20h + X86FSTENV32P.FPUDP], eax
mov [xBP - 20h + X86FSTENV32P.FPUDS], eax
; Load the merged and cleaned up environment.
fldenv [xBP - 20h]
;
; Now for SSE, if supported, where we'll restore everything as is.
;
%ifdef RT_ARCH_X86
; SSE supported (ecx preserved)?
extern NAME(rtNoCrtHasSse)
call NAME(rtNoCrtHasSse)
test al, al
jz .return_okay
%endif
cmp xCX, RT_NOCRT_FE_LAST_ENV
jb .sse_special_env
ldmxcsr [xCX + 28]
jmp .return_okay
.sse_special_env:
stmxcsr [xBP - 10h]
mov eax, [xBP - 10h]
and eax, ~(X86_MXCSR_XCPT_FLAGS | X86_MXCSR_XCPT_MASK | X86_MXCSR_RC_MASK | X86_MXCSR_DAZ | X86_MXCSR_FZ)
or eax, X86_MXCSR_RC_NEAREST | X86_MXCSR_DM
cmp xCX, RT_NOCRT_FE_NOMASK_ENV ; Only the NOMASK one differs here.
je .sse_special_load_eax
or eax, X86_MXCSR_RC_NEAREST | X86_MXCSR_XCPT_MASK ; default environment masks all exceptions
.sse_special_load_eax:
mov [xBP - 10h], eax
ldmxcsr [xBP - 10h]
;
; Return success.
;
.return_okay:
xor eax, eax
.return:
leave
ret
ENDPROC RT_NOCRT(fesetenv)
|
