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 // Announcing an external function.
  31 #define FUNC(name)                                                      \
  32         .globl  F(name);                                                \
  33         TYPE_FUNC(name);                                                \
  34         .macro  ENDFUNC; _ENDFUNC(name); .endm;                         \
  35         FUNC_PREHOOK(name);                                             \
  36 F(name):                                                                \
  37         FUNC_POSTHOOK(name)
  38
  39 // Marking the end of a function.
  40 #define _ENDFUNC(name)                                                  \
  41         .purgem ENDFUNC;                                                \
  42         SIZE_OBJ(name);                                                 \
  43         ENDFUNC_HOOK(name)
  44
  45 ///--------------------------------------------------------------------------
  46 /// ELF-specific hacking.
  47
  48 #if __ELF__
  49
  50 #if __PIC__ || __PIE__
  51 #  define WANT_PIC 1
  52 #endif
  53
  54 #define TYPE_FUNC(name) .type name, STT_FUNC
  55
  56 #define SIZE_OBJ(name) .size name, . - name
  57
  58 #endif
  59
  60 ///--------------------------------------------------------------------------
  61 /// Windows-specific hacking.
  62
  63 #if ABI_WIN
  64
  65 #if CPUFAM_X86
  66 #  define F(name) _##name
  67 #endif
  68
  69 #endif
  70
  71 ///--------------------------------------------------------------------------
  72 /// x86- and amd64-specific hacking.
  73 ///
  74 /// It's (slightly) easier to deal with both of these in one go.
  75
  76 #if CPUFAM_X86 || CPUFAM_AMD64
  77
  78 // Set the function hooks.
  79 #define FUNC_PREHOOK(_) .balign 16
  80
  81 // Don't use the wretched AT&T syntax.  It's festooned with pointless
  82 // punctuation, and all of the data movement is backwards.  Ugh!
  83         .intel_syntax noprefix
  84
  85 // Call external subroutine at ADDR, possibly via PLT.
  86         .macro  callext addr
  87 #if WANT_PIC
  88         call    \addr@PLT
  89 #else
  90         call    \addr
  91 #endif
  92         .endm
  93
  94 // Do I need to arrange a spare GOT register?
  95 #if WANT_PIC && CPUFAM_X86
  96 #  define NEED_GOT 1
  97 #endif
  98 #define GOTREG ebx                      // Not needed in AMD64 so don't care.
  99
 100 // Maybe load GOT address into GOT.
 101         .macro  ldgot got=GOTREG
 102 #if WANT_PIC && CPUFAM_X86
 103         call    _where_am_i.\got
 104         add     \got, offset _GLOBAL_OFFSET_TABLE_
 105 #endif
 106         .endm
 107
 108 // Maybe build a helper subroutine for `ldgot GOT'.
 109         .macro  gotaux got=GOTREG
 110 #if WANT_PIC && CPUFAM_X86
 111         .align  16
 112 _where_am_i.\got :
 113         mov     \got, [esp]
 114         ret
 115 #endif
 116         .endm
 117
 118 // Load address of external symbol ADDR into REG, maybe using GOT.
 119         .macro  leaext reg, addr, got=GOTREG
 120 #if WANT_PIC
 121 #  if CPUFAM_X86
 122         mov     \reg, [\got + \addr@GOT]
 123 #  endif
 124 #  if CPUFAM_AMD64
 125         mov     \reg, \addr@GOTPCREL[rip]
 126 #  endif
 127 #else
 128 #  if CPUFAM_X86
 129         mov     \reg, offset \addr
 130 #  endif
 131 #  if CPUFAM_AMD64
 132         lea     \reg, \addr[rip]
 133 #  endif
 134 #endif
 135         .endm
 136
 137 // Address expression (possibly using a base register, and a displacement)
 138 // referring to ADDR, which is within our module, maybe using GOT.
 139 #define INTADDR(...) INTADDR__0(__VA_ARGS__, GOTREG, dummy)
 140 #define INTADDR__0(addr, got, ...) INTADDR__1(addr, got)
 141 #if CPUFAM_AMD64
 142 #  define INTADDR__1(addr, got) addr + rip
 143 #elif WANT_PIC
 144 #  define INTADDR__1(addr, got) got + addr@GOTOFF
 145 #else
 146 #  define INTADDR__1(addr, got) addr
 147 #endif
 148
 149 #endif
 150
 151 ///--------------------------------------------------------------------------
 152 /// Final stuff.
 153
 154 // Default values for the various hooks.
 155 #ifndef FUNC_PREHOOK
 156 #  define FUNC_PREHOOK(name)
 157 #endif
 158 #ifndef FUNC_POSTHOOK
 159 #  define FUNC_POSTHOOK(name)
 160 #endif
 161 #ifndef ENDFUNC_HOOK
 162 #  define ENDFUNC_HOOK(name)
 163 #endif
 164
 165 #ifndef F
 166 #  define F(name) name
 167 #endif
 168
 169 #ifndef TYPE_FUNC
 170 #  define TYPE_FUNC(name)
 171 #endif
 172
 173 #ifndef SIZE_OBJ
 174 #  define SIZE_OBJ(name)
 175 #endif
 176
 177 ///----- That's all, folks --------------------------------------------------