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
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
; $Id: exp2f.asm $
;; @file
; IPRT - No-CRT exp2f - AMD64 & X86.
;
;
; Copyright (C) 2022-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
%define RT_ASM_WITH_SEH64
%include "iprt/asmdefs.mac"
%include "iprt/x86.mac"
BEGINCODE
;;
; Calculate two to the power of @a r32.
;
; @returns st(0) / xmm0
; @param r32 [rbp + 8] / xmm0
RT_NOCRT_BEGINPROC exp2f
push xBP
SEH64_PUSH_xBP
mov xBP, xSP
SEH64_SET_FRAME_xBP 0
%ifdef RT_ARCH_AMD64
sub xSP, 10h
SEH64_ALLOCATE_STACK 10h
%endif
SEH64_END_PROLOGUE
;
; Load the value into st(0).
;
%ifdef RT_ARCH_AMD64
movss [xSP], xmm0
fld dword [xSP]
%else
fld dword [xBP + xCB*2]
%endif
;
; Return immediately if NaN or infinity.
;
fxam
fstsw ax
test ax, X86_FSW_C0 ; C0 is set for NaN, Infinity and Empty register. The latter is not the case.
jz .input_ok
%ifdef RT_ARCH_AMD64
ffreep st0 ; return the xmm0 register value unchanged, as FLD changes SNaN to QNaN.
%endif
test ax, X86_FSW_C2 ; C2 is clear for NaN (and Empty) but set for Infinity.
jz .return_val2
test ax, X86_FSW_C1 ; C1 = sign bit
jz .return_val2 ; Not sign, return +Inf.
%ifndef RT_ARCH_AMD64
ffreep st0
%endif
fldz ; Signed, so return zero as that's a good approximation for 2**-Inf.
jmp .return_val
.input_ok:
;
; Split the job in two on the fraction and integer input parts.
;
fld st0 ; Push a copy of the input on the stack.
frndint ; st0 = (int)input
fsub st1, st0 ; st1 = input - (int)input; i.e. st1 = fraction, st0 = integer.
fxch ; st0 = fraction, st1 = integer.
; 1. Calculate on the fraction.
f2xm1 ; st0 = 2**fraction - 1.0
fld1
faddp ; st0 = 2**fraction
; 2. Apply the integer power of two.
fscale ; st0 = result; st1 = integer part of input.
fstp st1 ; st0 = result; no st1.
.return_val:
%ifdef RT_ARCH_AMD64
fstp dword [xSP]
movss xmm0, [xSP]
%endif
.return_val2:
leave
ret
ENDPROC RT_NOCRT(exp2f)
|
