xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/i386/floatdisf.S (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1*0b57cec5SDimitry Andric// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2*0b57cec5SDimitry Andric// See https://llvm.org/LICENSE.txt for license information.
3*0b57cec5SDimitry Andric// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4*0b57cec5SDimitry Andric
5*0b57cec5SDimitry Andric#include "../assembly.h"
6*0b57cec5SDimitry Andric
7*0b57cec5SDimitry Andric// float __floatdisf(di_int a);
8*0b57cec5SDimitry Andric
9*0b57cec5SDimitry Andric// This routine has some extra memory traffic, loading the 64-bit input via two
10*0b57cec5SDimitry Andric// 32-bit loads, then immediately storing it back to the stack via a single 64-bit
11*0b57cec5SDimitry Andric// store.  This is to avoid a write-small, read-large stall.
12*0b57cec5SDimitry Andric// However, if callers of this routine can be safely assumed to store the argument
13*0b57cec5SDimitry Andric// via a 64-bt store, this is unnecessary memory traffic, and should be avoided.
14*0b57cec5SDimitry Andric// It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro.
15*0b57cec5SDimitry Andric
16*0b57cec5SDimitry Andric#ifdef __i386__
17*0b57cec5SDimitry Andric
18*0b57cec5SDimitry Andric.text
19*0b57cec5SDimitry Andric.balign 4
20*0b57cec5SDimitry AndricDEFINE_COMPILERRT_FUNCTION(__floatdisf)
21*0b57cec5SDimitry Andric#ifndef TRUST_CALLERS_USE_64_BIT_STORES
22*0b57cec5SDimitry Andric	movd		4(%esp),	%xmm0
23*0b57cec5SDimitry Andric	movd		8(%esp),	%xmm1
24*0b57cec5SDimitry Andric	punpckldq	%xmm1,		%xmm0
25*0b57cec5SDimitry Andric	movq		%xmm0,		4(%esp)
26*0b57cec5SDimitry Andric#endif
27*0b57cec5SDimitry Andric	fildll		4(%esp)
28*0b57cec5SDimitry Andric	fstps		4(%esp)
29*0b57cec5SDimitry Andric	flds		4(%esp)
30*0b57cec5SDimitry Andric	ret
31*0b57cec5SDimitry AndricEND_COMPILERRT_FUNCTION(__floatdisf)
32*0b57cec5SDimitry Andric
33*0b57cec5SDimitry Andric#endif // __i386__
34*0b57cec5SDimitry Andric
35*0b57cec5SDimitry AndricNO_EXEC_STACK_DIRECTIVE
36*0b57cec5SDimitry Andric
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