mirror of https://github.com/acidanthera/audk.git
42 lines
1.7 KiB
NASM
42 lines
1.7 KiB
NASM
;------------------------------------------------------------------------------
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; Return the current FPU rounding mode.
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;
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; MASM implementation of the flt_rounds function from NetBSD.
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;
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; Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php.
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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;------------------------------------------------------------------------------
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.code
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;_map BYTE 1 ; round to nearest
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; BYTE 3 ; round to negative infinity
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; BYTE 2 ; round to positive infinity
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; BYTE 0 ; round to zero
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;------------------------------------------------------------------------------
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; int
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; EFIAPI
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; fpu_rmode( void );
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;
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; VC++ always creates space for 4 parameters on the stack, whether they are
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; used or not. We use one for temporary storage since the only variant of
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; fnstcw saves to memory, NOT a register.
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;------------------------------------------------------------------------------
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internal_FPU_rmode PROC
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fnstcw [rsp + 8] ; save 16-bit FPU Control Word
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mov eax, [rsp + 8] ; get the saved FPU Control Word
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shr eax, 10
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and rax, 3 ; index is only the LSB two bits in RAX
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ret ; Return rounding mode in RAX
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internal_FPU_rmode ENDP
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END
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