chiark - git - mdw - catacomb/blob - base/asm-common.h

   1 /// -*- mode: asm; asm-comment-char: ?/ -*-
   2 ///
   3 /// Fancy SIMD implementation of Salsa20
   4 ///
   5 /// (c) 2015 Straylight/Edgeware
   6 ///
   7
   8 ///----- Licensing notice ---------------------------------------------------
   9 ///
  10 /// This file is part of Catacomb.
  11 ///
  12 /// Catacomb is free software; you can redistribute it and/or modify
  13 /// it under the terms of the GNU Library General Public License as
  14 /// published by the Free Software Foundation; either version 2 of the
  15 /// License, or (at your option) any later version.
  16 ///
  17 /// Catacomb is distributed in the hope that it will be useful,
  18 /// but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 /// GNU Library General Public License for more details.
  21 ///
  22 /// You should have received a copy of the GNU Library General Public
  23 /// License along with Catacomb; if not, write to the Free
  24 /// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25 /// MA 02111-1307, USA.
  26
  27 ///--------------------------------------------------------------------------
  28 /// General definitions.
  29
  30 // Some useful variables.
  31         .L$_subsec = 0
  32
  33 // Literal pools done the hard way.
  34 #define _LIT .text .L$_subsec + 1
  35 #define _ENDLIT .text .L$_subsec
  36
  37 // Announcing an external function.
  38 #define FUNC(name)                                                      \
  39         .globl  F(name);                                                \
  40         TYPE_FUNC(name);                                                \
  41         .macro  ENDFUNC; _ENDFUNC(name); .endm;                         \
  42         FUNC_PREHOOK(name);                                             \
  43 F(name):                                                                \
  44         FUNC_POSTHOOK(name)
  45
  46 // Marking the end of a function.
  47 #define _ENDFUNC(name)                                                  \
  48         .purgem ENDFUNC;                                                \
  49         SIZE_OBJ(name);                                                 \
  50         ENDFUNC_HOOK(name);                                             \
  51         .L$_subsec = .L$_subsec + 2;                                    \
  52         .text .L$_subsec
  53
  54 ///--------------------------------------------------------------------------
  55 /// ELF-specific hacking.
  56
  57 #if __ELF__
  58
  59 #if __PIC__ || __PIE__
  60 #  define WANT_PIC 1
  61 #endif
  62
  63 #define TYPE_FUNC(name) .type name, STT_FUNC
  64
  65 #define SIZE_OBJ(name) .size name, . - name
  66
  67 #endif
  68
  69 ///--------------------------------------------------------------------------
  70 /// Windows-specific hacking.
  71
  72 #if ABI_WIN
  73
  74 #if CPUFAM_X86
  75 #  define F(name) _##name
  76 #endif
  77
  78 #endif
  79
  80 ///--------------------------------------------------------------------------
  81 /// x86- and amd64-specific hacking.
  82 ///
  83 /// It's (slightly) easier to deal with both of these in one go.
  84
  85 #if CPUFAM_X86 || CPUFAM_AMD64
  86
  87 // Set the function hooks.
  88 #define FUNC_PREHOOK(_) .balign 16
  89
  90 // Don't use the wretched AT&T syntax.  It's festooned with pointless
  91 // punctuation, and all of the data movement is backwards.  Ugh!
  92         .intel_syntax noprefix
  93
  94 // Call external subroutine at ADDR, possibly via PLT.
  95         .macro  callext addr
  96 #if WANT_PIC
  97         call    \addr@PLT
  98 #else
  99         call    \addr
 100 #endif
 101         .endm
 102
 103 // Do I need to arrange a spare GOT register?
 104 #if WANT_PIC && CPUFAM_X86
 105 #  define NEED_GOT 1
 106 #endif
 107 #define GOTREG ebx                      // Not needed in AMD64 so don't care.
 108
 109 // Maybe load GOT address into GOT.
 110         .macro  ldgot got=GOTREG
 111 #if WANT_PIC && CPUFAM_X86
 112         call    _where_am_i.\got
 113         add     \got, offset _GLOBAL_OFFSET_TABLE_
 114 #endif
 115         .endm
 116
 117 // Maybe build a helper subroutine for `ldgot GOT'.
 118         .macro  gotaux got=GOTREG
 119 #if WANT_PIC && CPUFAM_X86
 120         .align  16
 121 _where_am_i.\got :
 122         mov     \got, [esp]
 123         ret
 124 #endif
 125         .endm
 126
 127 // Load address of external symbol ADDR into REG, maybe using GOT.
 128         .macro  leaext reg, addr, got=GOTREG
 129 #if WANT_PIC
 130 #  if CPUFAM_X86
 131         mov     \reg, [\got + \addr@GOT]
 132 #  endif
 133 #  if CPUFAM_AMD64
 134         mov     \reg, \addr@GOTPCREL[rip]
 135 #  endif
 136 #else
 137 #  if CPUFAM_X86
 138         mov     \reg, offset \addr
 139 #  endif
 140 #  if CPUFAM_AMD64
 141         lea     \reg, \addr[rip]
 142 #  endif
 143 #endif
 144         .endm
 145
 146 // Address expression (possibly using a base register, and a displacement)
 147 // referring to ADDR, which is within our module, maybe using GOT.
 148 #define INTADDR(...) INTADDR__0(__VA_ARGS__, GOTREG, dummy)
 149 #define INTADDR__0(addr, got, ...) INTADDR__1(addr, got)
 150 #if CPUFAM_AMD64
 151 #  define INTADDR__1(addr, got) addr + rip
 152 #elif WANT_PIC
 153 #  define INTADDR__1(addr, got) got + addr@GOTOFF
 154 #else
 155 #  define INTADDR__1(addr, got) addr
 156 #endif
 157
 158 #endif
 159
 160 ///--------------------------------------------------------------------------
 161 /// ARM-specific hacking.
 162
 163 #if CPUFAM_ARM
 164
 165 // ARM/Thumb mode things.  Use ARM by default.
 166 #define ARM .arm; .L$_pcoff = 8
 167 #define THUMB .thumb; .L$_pcoff = 4
 168         ARM
 169
 170 // Set the function hooks.
 171 #define FUNC_PREHOOK(_) .balign 4
 172 #define ENDFUNC_HOOK(name) .ltorg
 173
 174 // Call external subroutine at ADDR, possibly via PLT.
 175         .macro  callext addr, cond=
 176 #if WANT_PIC
 177         bl\cond \addr(PLT)
 178 #else
 179         bl\cond \addr
 180 #endif
 181         .endm
 182
 183 // Do I need to arrange a spare GOT register?
 184 #if WANT_PIC
 185 #  define NEED_GOT 1
 186 #endif
 187 #define GOTREG r9
 188
 189 // Maybe load GOT address into GOT.
 190         .macro  ldgot   cond=, got=GOTREG
 191 #if WANT_PIC
 192         ldr\cond \got, .L$_ldgot$\@
 193 .L$_ldgot_pc$\@:
 194         add\cond \got, pc, \got
 195         _LIT
 196         .balign 4
 197 .L$_ldgot$\@:
 198         .word   _GLOBAL_OFFSET_TABLE_ - .L$_ldgot_pc$\@ - .L$_pcoff
 199         _ENDLIT
 200 #endif
 201         .endm
 202
 203 // Load address of external symbol ADDR into REG, maybe using GOT.
 204         .macro  leaext  reg, addr, cond=, got=GOTREG
 205 #if WANT_PIC
 206         ldr\cond \reg, .L$_leaext$\@
 207         ldr\cond \reg, [\got, \reg]
 208         _LIT
 209         .balign 4
 210 .L$_leaext$\@:
 211         .word   \addr(GOT)
 212         _ENDLIT
 213 #else
 214         ldr\cond \reg, =\addr
 215 #endif
 216         .endm
 217
 218 // Load address of external symbol ADDR into REG directly.
 219         .macro  leaextq reg, addr, cond=
 220 #if WANT_PIC
 221         ldr\cond \reg, .L$_leaextq$\@
 222 .L$_leaextq_pc$\@:
 223         .if     .L$_pcoff == 8
 224         ldr\cond \reg, [pc, \reg]
 225         .else
 226         add\cond \reg, pc
 227         ldr\cond \reg, [\reg]
 228         .endif
 229         _LIT
 230         .balign 4
 231 .L$_leaextq$\@:
 232         .word   \addr(GOT_PREL) + (. - .L$_leaextq_pc$\@ - .L$_pcoff)
 233         _ENDLIT
 234 #else
 235         ldr\cond \reg, =\addr
 236 #endif
 237         .endm
 238
 239 #endif
 240
 241 ///--------------------------------------------------------------------------
 242 /// Final stuff.
 243
 244 // Default values for the various hooks.
 245 #ifndef FUNC_PREHOOK
 246 #  define FUNC_PREHOOK(name)
 247 #endif
 248 #ifndef FUNC_POSTHOOK
 249 #  define FUNC_POSTHOOK(name)
 250 #endif
 251 #ifndef ENDFUNC_HOOK
 252 #  define ENDFUNC_HOOK(name)
 253 #endif
 254
 255 #ifndef F
 256 #  define F(name) name
 257 #endif
 258
 259 #ifndef TYPE_FUNC
 260 #  define TYPE_FUNC(name)
 261 #endif
 262
 263 #ifndef SIZE_OBJ
 264 #  define SIZE_OBJ(name)
 265 #endif
 266
 267 ///----- That's all, folks --------------------------------------------------