summaryrefslogtreecommitdiff
path: root/lib/i386/floatdidf.s
blob: 34736ac58d921ea49e868dd0455e3437dbd25034 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.

// double __floatundidf(du_int a);

#ifdef __i386__

.const
.align 4
twop52: .quad 0x4330000000000000
twop32: .quad 0x41f0000000000000

#define REL_ADDR(_a)	(_a)-0b(%eax)

.text
.align 4
.globl ___floatdidf
___floatdidf:
	cvtsi2sd	8(%esp),			%xmm1
	movss		4(%esp),			%xmm0 // low 32 bits of a
	calll		0f
0:	popl		%eax
	mulsd		REL_ADDR(twop32),	%xmm1 // a_hi as a double (without rounding)
	movsd		REL_ADDR(twop52),	%xmm2 // 0x1.0p52
	subsd		%xmm2,				%xmm1 // a_hi - 0x1p52 (no rounding occurs)
	orpd		%xmm2,				%xmm0 // 0x1p52 + a_lo (no rounding occurs)
	addsd		%xmm1,				%xmm0 // a_hi + a_lo   (round happens here)
	movsd		%xmm0,			   4(%esp)
	fldl	   4(%esp)
	ret
	
#endif // __i386__