99e1784525
This reverts commit 60a3cb9ad8.
Reason for revert: x87 instruction usage might not be as
clear cut as I would like. At the very least, llvm mingw
builds appear to having issues with emms.
Original change's description:
> remove fldcw/fstcw from Win64 builds
>
> _MCW_PC (Precision control) is not supported on x64:
> https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/control87-controlfp-control87-2
>
> The x87 FPU is not used on Win64 or ARM so setting the x87 control word
> is not necessary. The SSE/SSE2 and ARM FPUs don't have a precision
> control - the precision is embedded in each instruction - so the need to
> set the control word is also gone.
BUG=webm:1500
Change-Id: I25bcfa96bc9c860f6c7e03315d75fa6fd1d88ec5
34 lines
788 B
NASM
34 lines
788 B
NASM
;
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; Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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;
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; Use of this source code is governed by a BSD-style license
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; that can be found in the LICENSE file in the root of the source
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; tree. An additional intellectual property rights grant can be found
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; in the file PATENTS. All contributing project authors may
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; be found in the AUTHORS file in the root of the source tree.
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;
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%include "vpx_ports/x86_abi_support.asm"
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section .text
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%if LIBVPX_YASM_WIN64
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global sym(vpx_winx64_fldcw) PRIVATE
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sym(vpx_winx64_fldcw):
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sub rsp, 8
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mov [rsp], rcx ; win x64 specific
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fldcw [rsp]
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add rsp, 8
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ret
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global sym(vpx_winx64_fstcw) PRIVATE
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sym(vpx_winx64_fstcw):
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sub rsp, 8
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fstcw [rsp]
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mov rax, [rsp]
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add rsp, 8
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ret
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%endif
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