floatdidf.S revision 1.1.1.4 
1// This file is dual licensed under the MIT and the University of Illinois Open
2// Source Licenses. See LICENSE.TXT for details.
3
4#include "../assembly.h"
5
6// double __floatundidf(du_int a);
7
8#ifdef __i386__
9
10CONST_SECTION
11
12	.balign 16
13twop52:
14	.quad 0x4330000000000000
15
16	.balign 16
17twop32:
18	.quad 0x41f0000000000000
19
20#define REL_ADDR(_a)	(_a)-0b(%eax)
21
22.text
23.balign 4
24DEFINE_COMPILERRT_FUNCTION(__floatdidf)
25	cvtsi2sd	8(%esp),			%xmm1
26	movss		4(%esp),			%xmm0 // low 32 bits of a
27	calll		0f
280:	popl		%eax
29	mulsd		REL_ADDR(twop32),	%xmm1 // a_hi as a double (without rounding)
30	movsd		REL_ADDR(twop52),	%xmm2 // 0x1.0p52
31	subsd		%xmm2,				%xmm1 // a_hi - 0x1p52 (no rounding occurs)
32	orpd		%xmm2,				%xmm0 // 0x1p52 + a_lo (no rounding occurs)
33	addsd		%xmm1,				%xmm0 // a_hi + a_lo   (round happens here)
34	movsd		%xmm0,			   4(%esp)
35	fldl	   4(%esp)
36	ret
37END_COMPILERRT_FUNCTION(__floatdidf)
38
39#endif // __i386__
40