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 /// x86-specific hacking.
  62
  63 #if CPUFAM_X86
  64
  65 // Set the function hooks.
  66 #define FUNC_PREHOOK(_) .balign 16
  67
  68 // Don't use the wretched AT&T syntax.  It's festooned with pointless
  69 // punctuation, and all of the data movement is backwards.  Ugh!
  70         .intel_syntax noprefix
  71
  72 // Call external subroutine at ADDR, possibly via PLT.
  73         .macro  callext addr
  74 #if WANT_PIC
  75         call    \addr@PLT
  76 #else
  77         call    \addr
  78 #endif
  79         .endm
  80
  81 // Do I need to arrange a spare GOT register?
  82 #if WANT_PIC && CPUFAM_X86
  83 #  define NEED_GOT 1
  84 #endif
  85 #define GOTREG ebx                      // Not needed in AMD64 so don't care.
  86
  87 // Maybe load GOT address into GOT.
  88         .macro  ldgot got=GOTREG
  89 #if WANT_PIC
  90         call    _where_am_i.\got
  91         add     \got, offset _GLOBAL_OFFSET_TABLE_
  92 #endif
  93         .endm
  94
  95 // Maybe build a helper subroutine for `ldgot GOT'.
  96         .macro  gotaux got=GOTREG
  97 #if WANT_PIC
  98         .align  16
  99 _where_am_i.\got :
 100         mov     \got, [esp]
 101         ret
 102 #endif
 103         .endm
 104
 105 // Load address of external symbol ADDR into REG, maybe using GOT.
 106         .macro  leaext reg, addr, got=GOTREG
 107 #if WANT_PIC
 108         mov     \reg, [\got + \addr@GOT]
 109 #else
 110         mov     \reg, offset \addr
 111 #endif
 112         .endm
 113
 114 // Address expression (possibly using a base register, and a displacement)
 115 // referring to ADDR, which is within our module, maybe using GOT.
 116 #define INTADDR(...) INTADDR__0(__VA_ARGS__, GOTREG, dummy)
 117 #define INTADDR__0(addr, got, ...) INTADDR__1(addr, got)
 118 #if WANT_PIC
 119 #  define INTADDR__1(addr, got) got + addr@GOTOFF
 120 #else
 121 #  define INTADDR__1(addr, got) addr
 122 #endif
 123
 124 #endif
 125
 126 ///--------------------------------------------------------------------------
 127 /// Final stuff.
 128
 129 // Default values for the various hooks.
 130 #ifndef FUNC_PREHOOK
 131 #  define FUNC_PREHOOK(name)
 132 #endif
 133 #ifndef FUNC_POSTHOOK
 134 #  define FUNC_POSTHOOK(name)
 135 #endif
 136 #ifndef ENDFUNC_HOOK
 137 #  define ENDFUNC_HOOK(name)
 138 #endif
 139
 140 #ifndef F
 141 #  define F(name) name
 142 #endif
 143
 144 #ifndef TYPE_FUNC
 145 #  define TYPE_FUNC(name)
 146 #endif
 147
 148 #ifndef SIZE_OBJ
 149 #  define SIZE_OBJ(name)
 150 #endif
 151
 152 ///----- That's all, folks --------------------------------------------------