mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-03 13:13:30 +01:00
80 lines
2.1 KiB
NASM
Executable File
80 lines
2.1 KiB
NASM
Executable File
;------------------------------------------------------------------------------
|
|
;*
|
|
;* Copyright (c) 2009, 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.
|
|
;*
|
|
;*
|
|
;------------------------------------------------------------------------------
|
|
|
|
|
|
.686
|
|
.model flat,C
|
|
.const
|
|
;
|
|
; Float control word initial value:
|
|
; all exceptions masked, double-precision, round-to-nearest
|
|
;
|
|
mFpuControlWord DW 027Fh
|
|
;
|
|
; Multimedia-extensions control word:
|
|
; all exceptions masked, round-to-nearest, flush to zero for masked underflow
|
|
;
|
|
mMmxControlWord DD 01F80h
|
|
|
|
.xmm
|
|
.code
|
|
|
|
;
|
|
; Initializes floating point units for requirement of UEFI specification.
|
|
;
|
|
; This function initializes floating-point control word to 0x027F (all exceptions
|
|
; masked,double-precision, round-to-nearest) and multimedia-extensions control word
|
|
; (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero
|
|
; for masked underflow).
|
|
;
|
|
InitializeFloatingPointUnits PROC PUBLIC
|
|
|
|
push ebx
|
|
|
|
;
|
|
; Initialize floating point units
|
|
;
|
|
finit
|
|
fldcw mFpuControlWord
|
|
|
|
;
|
|
; Use CpuId instructuion (CPUID.01H:EDX.SSE[bit 25] = 1) to test
|
|
; whether the processor supports SSE instruction.
|
|
;
|
|
mov eax, 1
|
|
cpuid
|
|
bt edx, 25
|
|
jnc Done
|
|
|
|
;
|
|
; Set OSFXSR bit 9 in CR4
|
|
;
|
|
mov eax, cr4
|
|
or eax, BIT9
|
|
mov cr4, eax
|
|
|
|
;
|
|
; The processor should support SSE instruction and we can use
|
|
; ldmxcsr instruction
|
|
;
|
|
ldmxcsr mMmxControlWord
|
|
Done:
|
|
pop ebx
|
|
|
|
ret
|
|
|
|
InitializeFloatingPointUnits ENDP
|
|
|
|
END
|