#------------------------------------------------------------------------------ #* #* Copyright (c) 2009 - 2012, Intel Corporation. All rights reserved.
#* 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. #* #* #------------------------------------------------------------------------------ # # Initializes floating point units for requirement of UEFI specification. # # This function initializes floating-point control word to 0x037F (all exceptions # masked,double-extended-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). # ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits) ASM_PFX(InitializeFloatingPointUnits): # # Initialize floating point units # finit # # Float control word initial value: # all exceptions masked, double-precision, round-to-nearest # pushq $0x037F lea (%rsp), %rax fldcw (%rax) popq %rax # # Set OSFXSR bit 9 in CR4 # movq %cr4, %rax or $0x200, %rax movq %rax, %cr4 # # Multimedia-extensions control word: # all exceptions masked, round-to-nearest, flush to zero for masked underflow # pushq $0x01F80 lea (%rsp), %rax ldmxcsr (%rax) popq %rax ret