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1 /* `alloca' standard 4.2 subroutine for 68000's and 16000's and others.
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2 Also has _setjmp and _longjmp for pyramids.
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3 Copyright (C) 1985, 1986, 1988 Free Software Foundation, Inc.
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4
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5 This file is part of XEmacs.
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6
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7 XEmacs is free software; you can redistribute it and/or modify it
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8 under the terms of the GNU General Public License as published by the
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9 Free Software Foundation; either version 2, or (at your option) any
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10 later version.
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11
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12 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 for more details.
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16
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17 You should have received a copy of the GNU General Public License
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18 along with XEmacs; see the file COPYING. If not, write to
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19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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20 Boston, MA 02111-1307, USA. */
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21
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22 /* Synched up with: FSF 19.30. */
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23
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24 /* Both 68000 systems I have run this on have had broken versions of alloca.
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25 Also, I am told that non-berkeley systems do not have it at all.
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26 So replace whatever system-provided alloca there may be
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27 on all 68000 systems. */
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28
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29 #define NOT_C_CODE
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30 #ifdef emacs
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31 #include <config.h>
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32 #else
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33 #include "config.h"
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34 #endif
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35
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36 #ifndef HAVE_ALLOCA /* define this to use system's alloca */
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37
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38 #ifndef hp9000s300
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39 #ifndef m68k
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40 #ifndef m68000
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41 #ifndef WICAT
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42 #ifndef ns32000
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43 #ifndef ns16000
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44 #ifndef sequent
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45 #ifndef pyramid
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46 #ifndef ATT3B5
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47 #ifndef XENIX
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48 you
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49 lose!!
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50 #endif /* XENIX */
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51 #endif /* ATT3B5 */
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52 #endif /* pyramid */
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53 #endif /* sequent */
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54 #endif /* ns16000 */
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55 #endif /* ns32000 */
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56 #endif /* WICAT */
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57 #endif /* m68000 */
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58 #endif /* m68k */
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59 #endif /* hp9000s300 */
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60
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61
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62 #ifdef hp9000s300
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63 #ifdef OLD_HP_ASSEMBLER
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64 data
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65 text
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66 globl _alloca
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67 _alloca
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68 move.l (sp)+,a0 ; pop return addr from top of stack
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69 move.l (sp)+,d0 ; pop size in bytes from top of stack
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70 add.l #ROUND,d0 ; round size up to long word
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71 and.l #MASK,d0 ; mask out lower two bits of size
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72 sub.l d0,sp ; allocate by moving stack pointer
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73 tst.b PROBE(sp) ; stack probe to allocate pages
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74 move.l sp,d0 ; return pointer
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75 add.l #-4,sp ; new top of stack
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76 jmp (a0) ; not a normal return
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77 MASK equ -4 ; Longword alignment
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78 ROUND equ 3 ; ditto
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79 PROBE equ -128 ; safety buffer for C compiler scratch
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80 data
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81 #else /* new hp assembler syntax */
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82 /*
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83 The new compiler does "move.m <registers> (%sp)" to save registers,
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84 so we must copy the saved registers when we mung the sp.
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85 The old compiler did "move.m <register> <offset>(%a6)", which
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86 gave us no trouble
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87 */
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88 text
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89 set PROBE,-128 # safety for C frame temporaries
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90 set MAXREG,22 # d2-d7, a2-a5, fp2-fp7 may have been saved
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91 global _alloca
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92 _alloca:
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93 mov.l (%sp)+,%a0 # return address
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94 mov.l (%sp)+,%d0 # number of bytes to allocate
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95 mov.l %sp,%a1 # save old sp for register copy
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96 mov.l %sp,%d1 # compute new sp
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97 sub.l %d0,%d1 # space requested
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98 and.l &-4,%d1 # round down to longword
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99 sub.l &MAXREG*4,%d1 # space for saving registers
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100 mov.l %d1,%sp # save new value of sp
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101 tst.b PROBE(%sp) # create pages (sigh)
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102 mov.l %a2,%d1 # save reg a2
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103 mov.l %sp,%a2
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104 move.w &MAXREG-1,%d0
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105 copy_regs_loop: /* save caller's saved registers */
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106 mov.l (%a1)+,(%a2)+
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107 dbra %d0,copy_regs_loop
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108 mov.l %a2,%d0 # return value
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109 mov.l %d1,%a2 # restore a2
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110 add.l &-4,%sp # adjust tos
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111 jmp (%a0) # rts
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112 #endif /* new hp assembler */
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113 #else
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114 #ifdef m68k /* SGS assembler totally different */
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115 file "alloca.s"
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116 global alloca
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117 alloca:
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118 #ifdef MOTOROLA_DELTA
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119 /* slightly modified version of alloca to motorola sysV/68 pcc - based
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120 compiler.
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121 this compiler saves used registers relative to %sp instead of %fp.
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122 alright, just make new copy of saved register set whenever we allocate
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123 new space from stack..
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124 this is true at last until SVR3V7 . bug has reported to Motorola. */
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125 set MAXREG,10 # max no of registers to save (d2-d7, a2-a5)
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126 mov.l (%sp)+,%a1 # pop return addr from top of stack
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127 mov.l (%sp)+,%d0 # pop size in bytes from top of stack
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128 mov.l %sp,%a0 # save stack pointer for register copy
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129 addq.l &3,%d0 # round size up to long word
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130 andi.l &-4,%d0 # mask out lower two bits of size
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131 mov.l %sp,%d1 # compute new value of sp to d1
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132 sub.l %d0,%d1 # pseudo-allocate by moving stack pointer
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133 sub.l &MAXREG*4,%d1 # allocate more space for saved regs.
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134 mov.l %d1,%sp # actual allocation.
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135 move.w &MAXREG-1,%d0 # d0 counts saved regs.
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136 mov.l %a2,%d1 # preserve a2.
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137 mov.l %sp,%a2 # make pointer to new reg save area.
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138 copy_regs_loop: # copy stuff from old save area.
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139 mov.l (%a0)+,(%a2)+ # save saved register
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140 dbra %d0,copy_regs_loop
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141 mov.l %a2,%a0 # now a2 is start of allocated space.
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142 mov.l %a2,%d0 # return it in both a0 and d0 to play safe.
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143 mov.l %d1,%a2 # restore a2.
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144 subq.l &4,%sp # new top of stack
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145 jmp (%a1) # far below normal return
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146 #else /* not MOTOROLA_DELTA */
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147 mov.l (%sp)+,%a1 # pop return addr from top of stack
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148 mov.l (%sp)+,%d0 # pop size in bytes from top of stack
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149 add.l &R%1,%d0 # round size up to long word
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150 and.l &-4,%d0 # mask out lower two bits of size
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151 sub.l %d0,%sp # allocate by moving stack pointer
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152 tst.b P%1(%sp) # stack probe to allocate pages
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153 mov.l %sp,%a0 # return pointer as pointer
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154 mov.l %sp,%d0 # return pointer as int to avoid disaster
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155 add.l &-4,%sp # new top of stack
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156 jmp (%a1) # not a normal return
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157 set S%1,64 # safety factor for C compiler scratch
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158 set R%1,3+S%1 # add to size for rounding
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159 set P%1,-132 # probe this far below current top of stack
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160 #endif /* not MOTOROLA_DELTA */
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161
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162 #else /* not m68k */
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163
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164 #ifdef m68000
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165
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166 #ifdef WICAT
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167 /*
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168 * Registers are saved after the corresponding link so we have to explicitly
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169 * move them to the top of the stack where they are expected to be.
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170 * Since we do not know how many registers were saved in the calling function
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171 * we must assume the maximum possible (d2-d7,a2-a5). Hence, we end up
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172 * wasting some space on the stack.
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173 *
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174 * The large probe (tst.b) attempts to make up for the fact that we have
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175 * potentially used up the space that the caller probed for its own needs.
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176 */
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177 .procss m0
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178 .config "68000 1"
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179 .module _alloca
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180 MAXREG: .const 10
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181 .sect text
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182 .global _alloca
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183 _alloca:
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184 move.l (sp)+,a1 ; pop return address
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185 move.l (sp)+,d0 ; pop allocation size
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186 move.l sp,d1 ; get current SP value
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187 sub.l d0,d1 ; adjust to reflect required size...
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188 sub.l #MAXREG*4,d1 ; ...and space needed for registers
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189 and.l #-4,d1 ; backup to longword boundry
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190 move.l sp,a0 ; save old SP value for register copy
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191 move.l d1,sp ; set the new SP value
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192 tst.b -4096(sp) ; grab an extra page (to cover caller)
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193 move.l a2,d1 ; save callers register
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194 move.l sp,a2
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195 move.w #MAXREG-1,d0 ; # of longwords to copy
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196 loop: move.l (a0)+,(a2)+ ; copy registers...
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197 dbra d0,loop ; ...til there are no more
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198 move.l a2,d0 ; end of register area is addr for new space
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199 move.l d1,a2 ; restore saved a2.
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200 addq.l #4,sp ; caller will increment sp by 4 after return.
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201 move.l d0,a0 ; return value in both a0 and d0.
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202 jmp (a1)
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203 .end _alloca
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204 #else
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205
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206 /* Some systems want the _, some do not. Win with both kinds. */
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207 .globl _alloca
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208 _alloca:
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209 .globl alloca
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210 alloca:
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211 movl sp@+,a0
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212 movl a7,d0
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213 subl sp@,d0
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214 andl #~3,d0
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215 movl d0,sp
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216 tstb sp@(0) /* Make stack pages exist */
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217 /* Needed on certain systems
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218 that lack true demand paging */
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219 addql #4,d0
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220 jmp a0@
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221
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222 #endif /* not WICAT */
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223 #endif /* m68000 */
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224 #endif /* not m68k */
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225 #endif /* not hp9000s300 */
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226
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227 #if defined (ns16000) || defined (ns32000)
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228
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229 .text
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230 .align 2
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231 /* Some systems want the _, some do not. Win with both kinds. */
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232 .globl _alloca
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233 _alloca:
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234 .globl alloca
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235 alloca:
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236
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237 /* Two different assembler syntaxes are used for the same code
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238 on different systems. */
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239
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240 #ifdef sequent
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241 #define IM
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242 #define REGISTER(x) x
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243 #else
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244 #ifdef NS5 /* ns SysV assembler */
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245 #define IM $
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246 #define REGISTER(x) x
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247 #else
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248 #define IM $
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249 #define REGISTER(x) 0(x)
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250 #endif
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251 #endif
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252
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253 /*
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254 * The ns16000 is a little more difficult, need to copy regs.
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255 * Also the code assumes direct linkage call sequence (no mod table crap).
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256 * We have to copy registers, and therefore waste 32 bytes.
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257 *
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258 * Stack layout:
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259 * new sp -> junk
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260 * registers (copy)
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261 * r0 -> new data
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262 * | (orig retval)
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263 * | (orig arg)
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264 * old sp -> regs (orig)
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265 * local data
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266 * fp -> old fp
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267 */
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268
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269 movd tos,r1 /* pop return addr */
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270 negd tos,r0 /* pop amount to allocate */
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271 sprd sp,r2
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272 addd r2,r0
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273 bicb IM/**/3,r0 /* 4-byte align */
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274 lprd sp,r0
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275 adjspb IM/**/36 /* space for regs, +4 for caller to pop */
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276 movmd 0(r2),4(sp),IM/**/4 /* copy regs */
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277 movmd 0x10(r2),0x14(sp),IM/**/4
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278 jump REGISTER(r1) /* funky return */
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279 #endif /* ns16000 or ns32000 */
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280
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281 #ifdef pyramid
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282
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283 .globl _alloca
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284
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285 _alloca: addw $3,pr0 # add 3 (dec) to first argument
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286 bicw $3,pr0 # then clear its last 2 bits
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287 subw pr0,sp # subtract from SP the val in PR0
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288 andw $-32,sp # keep sp aligned on multiple of 32.
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289 movw sp,pr0 # ret. current SP
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290 ret
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291
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292 #ifdef PYRAMID_OLD /* This isn't needed in system version 4. */
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293 .globl __longjmp
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294 .globl _longjmp
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295 .globl __setjmp
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296 .globl _setjmp
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297
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298 __longjmp: jump _longjmp
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299 __setjmp: jump _setjmp
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300 #endif
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301
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302 #endif /* pyramid */
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303
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304 #ifdef ATT3B5
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305
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306 .align 4
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307 .globl alloca
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308
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309 alloca:
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310 movw %ap, %r8
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311 subw2 $9*4, %r8
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312 movw 0(%r8), %r1 /* pc */
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313 movw 4(%r8), %fp
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314 movw 8(%r8), %sp
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315 addw2 %r0, %sp /* make room */
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316 movw %sp, %r0 /* return value */
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317 jmp (%r1) /* continue... */
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318
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319 #endif /* ATT3B5 */
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320
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321 #ifdef XENIX
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322
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323 .386
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324
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325 _TEXT segment dword use32 public 'CODE'
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326 assume cs:_TEXT
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327
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328 ;-------------------------------------------------------------------------
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329
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330 public _alloca
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331 _alloca proc near
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332
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333 pop ecx ; return address
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334 pop eax ; amount to alloc
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335 add eax,3 ; round it to 32-bit boundary
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336 and al,11111100B ;
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337 mov edx,esp ; current sp in edx
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338 sub edx,eax ; lower the stack
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339 xchg esp,edx ; start of allocation in esp, old sp in edx
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340 mov eax,esp ; return ptr to base in eax
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341 push [edx+8] ; save poss. stored reg. values (esi,edi,ebx)
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342 push [edx+4] ; on lowered stack
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343 push [edx] ;
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344 sub esp,4 ; allow for 'add esp, 4'
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345 jmp ecx ; jump to return address
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346
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347 _alloca endp
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348
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349 _TEXT ends
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350
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351 end
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352
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353 #endif /* XENIX */
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354
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355 #endif /* not HAVE_ALLOCA */
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