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GCC uses x87 floating point instructions when building 32-bit x86 |
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code by default. This is true even for x86-64 multilib. |
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|
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Using the x87 floating point unit can lead to strange behavior when |
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calculating intermediate values for single and double precision floats. |
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It uses 80 bits for all calculations, which is larger than the 32 or 64 |
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bits specified for floats and doubles. |
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|
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Using the SSE2 instructions available on x86-64 for floating point |
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arithmetic leads to more consistent behavior, and is usually faster. |
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|
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Reference: https://gcc.gnu.org/wiki/x87note |
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Signed-off-by: Mike Gilbert <floppym@g.o> |
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--- |
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profiles/arch/amd64/make.defaults | 4 ++-- |
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1 file changed, 2 insertions(+), 2 deletions(-) |
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|
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diff --git a/profiles/arch/amd64/make.defaults b/profiles/arch/amd64/make.defaults |
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index 0c05dec124e..e7e18ff6a91 100644 |
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--- a/profiles/arch/amd64/make.defaults |
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+++ b/profiles/arch/amd64/make.defaults |
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@@ -1,4 +1,4 @@ |
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-# Copyright 1999-2021 Gentoo Authors |
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+# Copyright 1999-2022 Gentoo Authors |
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# Distributed under the terms of the GNU General Public License v2 |
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|
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ARCH="amd64" |
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@@ -28,7 +28,7 @@ LDFLAGS_amd64="-m elf_x86_64" |
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CHOST_amd64="x86_64-pc-linux-gnu" |
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|
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# 32bit specific settings. |
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-CFLAGS_x86="-m32" |
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+CFLAGS_x86="-m32 -mfpmath=sse" |
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LDFLAGS_x86="-m elf_i386" |
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CHOST_x86="i686-pc-linux-gnu" |
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|
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-- |
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2.37.3 |
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