xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/i386/floatdisf.S (revision 3cab2bb3f667058bece8e38b12449a63a9d73c4b)
1*3cab2bb3Spatrick// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2*3cab2bb3Spatrick// See https://llvm.org/LICENSE.txt for license information.
3*3cab2bb3Spatrick// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4*3cab2bb3Spatrick
5*3cab2bb3Spatrick#include "../assembly.h"
6*3cab2bb3Spatrick
7*3cab2bb3Spatrick// float __floatdisf(di_int a);
8*3cab2bb3Spatrick
9*3cab2bb3Spatrick// This routine has some extra memory traffic, loading the 64-bit input via two
10*3cab2bb3Spatrick// 32-bit loads, then immediately storing it back to the stack via a single 64-bit
11*3cab2bb3Spatrick// store.  This is to avoid a write-small, read-large stall.
12*3cab2bb3Spatrick// However, if callers of this routine can be safely assumed to store the argument
13*3cab2bb3Spatrick// via a 64-bt store, this is unnecessary memory traffic, and should be avoided.
14*3cab2bb3Spatrick// It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro.
15*3cab2bb3Spatrick
16*3cab2bb3Spatrick#ifdef __i386__
17*3cab2bb3Spatrick
18*3cab2bb3Spatrick.text
19*3cab2bb3Spatrick.balign 4
20*3cab2bb3SpatrickDEFINE_COMPILERRT_FUNCTION(__floatdisf)
21*3cab2bb3Spatrick#ifndef TRUST_CALLERS_USE_64_BIT_STORES
22*3cab2bb3Spatrick	movd		4(%esp),	%xmm0
23*3cab2bb3Spatrick	movd		8(%esp),	%xmm1
24*3cab2bb3Spatrick	punpckldq	%xmm1,		%xmm0
25*3cab2bb3Spatrick	movq		%xmm0,		4(%esp)
26*3cab2bb3Spatrick#endif
27*3cab2bb3Spatrick	fildll		4(%esp)
28*3cab2bb3Spatrick	fstps		4(%esp)
29*3cab2bb3Spatrick	flds		4(%esp)
30*3cab2bb3Spatrick	ret
31*3cab2bb3SpatrickEND_COMPILERRT_FUNCTION(__floatdisf)
32*3cab2bb3Spatrick
33*3cab2bb3Spatrick#endif // __i386__
34*3cab2bb3Spatrick
35*3cab2bb3SpatrickNO_EXEC_STACK_DIRECTIVE
36*3cab2bb3Spatrick
37