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asm.h
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1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_X86_ASM_H
22 #define AVUTIL_X86_ASM_H
23 
24 #include <stdint.h>
25 #include "config.h"
26 
27 typedef struct xmm_reg { uint64_t a, b; } xmm_reg;
28 typedef struct ymm_reg { uint64_t a, b, c, d; } ymm_reg;
29 
30 #if ARCH_X86_64
31 # define OPSIZE "q"
32 # define REG_a "rax"
33 # define REG_b "rbx"
34 # define REG_c "rcx"
35 # define REG_d "rdx"
36 # define REG_D "rdi"
37 # define REG_S "rsi"
38 # define PTR_SIZE "8"
39 typedef int64_t x86_reg;
40 
41 # define REG_SP "rsp"
42 # define REG_BP "rbp"
43 # define REGBP rbp
44 # define REGa rax
45 # define REGb rbx
46 # define REGc rcx
47 # define REGd rdx
48 # define REGSP rsp
49 
50 #elif ARCH_X86_32
51 
52 # define OPSIZE "l"
53 # define REG_a "eax"
54 # define REG_b "ebx"
55 # define REG_c "ecx"
56 # define REG_d "edx"
57 # define REG_D "edi"
58 # define REG_S "esi"
59 # define PTR_SIZE "4"
60 typedef int32_t x86_reg;
61 
62 # define REG_SP "esp"
63 # define REG_BP "ebp"
64 # define REGBP ebp
65 # define REGa eax
66 # define REGb ebx
67 # define REGc ecx
68 # define REGd edx
69 # define REGSP esp
70 #else
71 typedef int x86_reg;
72 #endif
73 
74 #define HAVE_7REGS (ARCH_X86_64 || (HAVE_EBX_AVAILABLE && HAVE_EBP_AVAILABLE))
75 #define HAVE_6REGS (ARCH_X86_64 || (HAVE_EBX_AVAILABLE || HAVE_EBP_AVAILABLE))
76 
77 #if ARCH_X86_64 && defined(PIC)
78 # define BROKEN_RELOCATIONS 1
79 #endif
80 
81 /*
82  * If gcc is not set to support sse (-msse) it will not accept xmm registers
83  * in the clobber list for inline asm. XMM_CLOBBERS takes a list of xmm
84  * registers to be marked as clobbered and evaluates to nothing if they are
85  * not supported, or to the list itself if they are supported. Since a clobber
86  * list may not be empty, XMM_CLOBBERS_ONLY should be used if the xmm
87  * registers are the only in the clobber list.
88  * For example a list with "eax" and "xmm0" as clobbers should become:
89  * : XMM_CLOBBERS("xmm0",) "eax"
90  * and a list with only "xmm0" should become:
91  * XMM_CLOBBERS_ONLY("xmm0")
92  */
93 #if HAVE_XMM_CLOBBERS
94 # define XMM_CLOBBERS(...) __VA_ARGS__
95 # define XMM_CLOBBERS_ONLY(...) : __VA_ARGS__
96 #else
97 # define XMM_CLOBBERS(...)
98 # define XMM_CLOBBERS_ONLY(...)
99 #endif
100 
101 /* Use to export labels from asm. */
102 #define LABEL_MANGLE(a) EXTERN_PREFIX #a
103 
104 // Use rip-relative addressing if compiling PIC code on x86-64.
105 #if ARCH_X86_64 && defined(PIC)
106 # define LOCAL_MANGLE(a) #a "(%%rip)"
107 #else
108 # define LOCAL_MANGLE(a) #a
109 #endif
110 
111 #if HAVE_INLINE_ASM_DIRECT_SYMBOL_REFS
112 # define MANGLE(a) EXTERN_PREFIX LOCAL_MANGLE(a)
113 # define NAMED_CONSTRAINTS_ADD(...)
114 # define NAMED_CONSTRAINTS(...)
115 # define NAMED_CONSTRAINTS_ARRAY_ADD(...)
116 # define NAMED_CONSTRAINTS_ARRAY(...)
117 #else
118  /* When direct symbol references are used in code passed to a compiler that does not support them
119  * then these references need to be converted to named asm constraints instead.
120  * Instead of returning a direct symbol MANGLE now returns a named constraint for that specific symbol.
121  * In order for this to work there must also be a corresponding entry in the asm-interface. To add this
122  * entry use the macro NAMED_CONSTRAINTS() and pass in a list of each symbol reference used in the
123  * corresponding block of code. (e.g. NAMED_CONSTRAINTS(var1,var2,var3) where var1 is the first symbol etc. ).
124  * If there are already existing constraints then use NAMED_CONSTRAINTS_ADD to add to the existing constraint list.
125  */
126 # define MANGLE(a) "%["#a"]"
127  // Intel/MSVC does not correctly expand va-args so we need a rather ugly hack in order to get it to work
128 # define FE_0(P,X) P(X)
129 # define FE_1(P,X,X1) P(X), FE_0(P,X1)
130 # define FE_2(P,X,X1,X2) P(X), FE_1(P,X1,X2)
131 # define FE_3(P,X,X1,X2,X3) P(X), FE_2(P,X1,X2,X3)
132 # define FE_4(P,X,X1,X2,X3,X4) P(X), FE_3(P,X1,X2,X3,X4)
133 # define FE_5(P,X,X1,X2,X3,X4,X5) P(X), FE_4(P,X1,X2,X3,X4,X5)
134 # define FE_6(P,X,X1,X2,X3,X4,X5,X6) P(X), FE_5(P,X1,X2,X3,X4,X5,X6)
135 # define FE_7(P,X,X1,X2,X3,X4,X5,X6,X7) P(X), FE_6(P,X1,X2,X3,X4,X5,X6,X7)
136 # define FE_8(P,X,X1,X2,X3,X4,X5,X6,X7,X8) P(X), FE_7(P,X1,X2,X3,X4,X5,X6,X7,X8)
137 # define FE_9(P,X,X1,X2,X3,X4,X5,X6,X7,X8,X9) P(X), FE_8(P,X1,X2,X3,X4,X5,X6,X7,X8,X9)
138 # define GET_FE_IMPL(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,NAME,...) NAME
139 # define GET_FE(A) GET_FE_IMPL A
140 # define GET_FE_GLUE(x, y) x y
141 # define FOR_EACH_VA(P,...) GET_FE_GLUE(GET_FE((__VA_ARGS__,FE_9,FE_8,FE_7,FE_6,FE_5,FE_4,FE_3,FE_2,FE_1,FE_0)), (P,__VA_ARGS__))
142 # define NAME_CONSTRAINT(x) [x] "m"(x)
143  // Parameters are a list of each symbol reference required
144 # define NAMED_CONSTRAINTS_ADD(...) , FOR_EACH_VA(NAME_CONSTRAINT,__VA_ARGS__)
145  // Same but without comma for when there are no previously defined constraints
146 # define NAMED_CONSTRAINTS(...) FOR_EACH_VA(NAME_CONSTRAINT,__VA_ARGS__)
147  // Same as above NAMED_CONSTRAINTS except used for passing arrays/pointers instead of normal variables
148 # define NAME_CONSTRAINT_ARRAY(x) [x] "m"(*x)
149 # define NAMED_CONSTRAINTS_ARRAY_ADD(...) , FOR_EACH_VA(NAME_CONSTRAINT_ARRAY,__VA_ARGS__)
150 # define NAMED_CONSTRAINTS_ARRAY(...) FOR_EACH_VA(NAME_CONSTRAINT_ARRAY,__VA_ARGS__)
151 #endif
152 
153 #endif /* AVUTIL_X86_ASM_H */