path: root/src/math/x32/remainderl.s
diff options
authorSzabolcs Nagy <>2014-11-05 21:40:29 +0100
committerRich Felker <>2015-03-30 01:41:32 -0400
commit8c245bf2725f3171ee8f58dab7169e5d682de026 (patch)
treeae92d5d0536aa3b15adb96d62b4487488998e5a8 /src/math/x32/remainderl.s
parente48fff8d338d85616dc650cc8b4dd5ae00083da1 (diff)
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. (cherry picked from commit a732e80d33b4fd6f510f7cec4f5573ef5d89bc4e)
Diffstat (limited to 'src/math/x32/remainderl.s')
1 files changed, 2 insertions, 2 deletions
diff --git a/src/math/x32/remainderl.s b/src/math/x32/remainderl.s
index c97f68ad..79bf4feb 100644
--- a/src/math/x32/remainderl.s
+++ b/src/math/x32/remainderl.s
@@ -5,7 +5,7 @@ remainderl:
fldt 8(%esp)
1: fprem1
fstsw %ax
- sahf
- jp 1b
+ testb $4,%ah
+ jnz 1b
fstp %st(1)