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authorSzabolcs Nagy <nsz@port70.net>2014-11-05 21:40:29 +0100
committerSzabolcs Nagy <nsz@port70.net>2014-11-05 21:40:29 +0100
commita732e80d33b4fd6f510f7cec4f5573ef5d89bc4e (patch)
tree66494d38f5374808c3816c83395d5f5850abb607 /src/math/__signbitf.c
parentde2b9c21d94e0b76b629fec0060d043f535eef01 (diff)
downloadmusl-a732e80d33b4fd6f510f7cec4f5573ef5d89bc4e.tar.gz
math: fix x86_64 and x32 asm not to use sahf instruction
Some early x86_64 cpus (released before 2006) did not support sahf/lahf instructions so they should be avoided (intel manual says they are only supported if CPUID.80000001H:ECX.LAHF-SAHF[bit 0] = 1). The workaround simplifies exp2l and expm1l because fucomip can be used instead of the fucomp;fnstsw;sahf sequence copied from i386. In fmodl and remainderl sahf is replaced by a simple bit test.
Diffstat (limited to 'src/math/__signbitf.c')
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