VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/string/memcmp.asm@ 81106

Last change on this file since 81106 was 76553, checked in by vboxsync, 6 years ago

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File size: 3.4 KB
Line 
1; $Id: memcmp.asm 76553 2019-01-01 01:45:53Z vboxsync $
2;; @file
3; IPRT - No-CRT memcmp - AMD64 & X86.
4;
5
6;
7; Copyright (C) 2006-2019 Oracle Corporation
8;
9; This file is part of VirtualBox Open Source Edition (OSE), as
10; available from http://www.virtualbox.org. This file is free software;
11; you can redistribute it and/or modify it under the terms of the GNU
12; General Public License (GPL) as published by the Free Software
13; Foundation, in version 2 as it comes in the "COPYING" file of the
14; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16;
17; The contents of this file may alternatively be used under the terms
18; of the Common Development and Distribution License Version 1.0
19; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20; VirtualBox OSE distribution, in which case the provisions of the
21; CDDL are applicable instead of those of the GPL.
22;
23; You may elect to license modified versions of this file under the
24; terms and conditions of either the GPL or the CDDL or both.
25;
26
27%include "iprt/asmdefs.mac"
28
29BEGINCODE
30
31;;
32; @param pv1 gcc: rdi msc: rcx x86:[esp+4] wcall: eax
33; @param pv2 gcc: rsi msc: rdx x86:[esp+8] wcall: edx
34; @param cb gcc: rdx msc: r8 x86:[esp+0ch] wcall: ebx
35RT_NOCRT_BEGINPROC memcmp
36 cld
37
38 ; Do the bulk of the work.
39%ifdef RT_ARCH_AMD64
40 %ifdef ASM_CALL64_MSC
41 mov r10, rdi ; save
42 mov r11, rsi ; save
43 mov rdi, rcx
44 mov rsi, rdx
45 mov rcx, r8
46 mov rdx, r8
47 %else
48 mov rcx, rdx
49 %endif
50 shr rcx, 3
51 xor eax, eax
52 repe cmpsq
53 jne .not_equal_qword
54%else
55 push edi
56 push esi
57
58 %ifdef ASM_CALL32_WATCOM
59 mov edi, eax
60 mov esi, edx
61 mov ecx, ebx
62 mov edx, ebx
63 %else
64 mov ecx, [esp + 0ch + 8]
65 mov edi, [esp + 04h + 8]
66 mov esi, [esp + 08h + 8]
67 mov edx, ecx
68 %endif
69 jecxz .done
70 shr ecx, 2
71 xor eax, eax
72 repe cmpsd
73 jne .not_equal_dword
74%endif
75
76 ; The remaining bytes.
77%ifdef RT_ARCH_AMD64
78 test dl, 4
79 jz .dont_cmp_dword
80 cmpsd
81 jne .not_equal_dword
82%endif
83.dont_cmp_dword:
84 test dl, 2
85 jz .dont_cmp_word
86 cmpsw
87 jne .not_equal_word
88.dont_cmp_word:
89 test dl, 1
90 jz .dont_cmp_byte
91 cmpsb
92 jne .not_equal_byte
93.dont_cmp_byte:
94
95.done:
96%ifdef RT_ARCH_AMD64
97 %ifdef ASM_CALL64_MSC
98 mov rdi, r10
99 mov rsi, r11
100 %endif
101%else
102 pop esi
103 pop edi
104%endif
105 ret
106
107;
108; Mismatches.
109;
110%ifdef RT_ARCH_AMD64
111.not_equal_qword:
112 mov ecx, 8
113 sub rsi, 8
114 sub rdi, 8
115 repe cmpsb
116.not_equal_byte:
117 mov al, [xDI-1]
118 movzx ecx, byte [xSI-1]
119 sub eax, ecx
120 jmp .done
121%endif
122
123.not_equal_dword:
124 mov ecx, 4
125 sub xSI, 4
126 sub xDI, 4
127 repe cmpsb
128%ifdef RT_ARCH_AMD64
129 jmp .not_equal_byte
130%else
131.not_equal_byte:
132 mov al, [xDI-1]
133 movzx ecx, byte [xSI-1]
134 sub eax, ecx
135 jmp .done
136%endif
137
138.not_equal_word:
139 mov ecx, 2
140 sub xSI, 2
141 sub xDI, 2
142 repe cmpsb
143 jmp .not_equal_byte
144ENDPROC RT_NOCRT(memcmp)
145
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