sysdeps/powerpc/powerpc32/bp-asm.h

   1 /* Bounded-pointer definitions for PowerPC assembler.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    Contributed by Greg McGary <greg@mcgary.org>
   4    This file is part of the GNU C Library.  Its master source is NOT part of
   5    the C library, however.  The master source lives in the GNU MP Library.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #if __BOUNDED_POINTERS__
  22
  23 /* Byte offsets of BP components.  */
  24 # define oVALUE 0
  25 # define oLOW   4
  26 # define oHIGH  8
  27
  28 /* Don't check bounds, just convert the BP register to its simple
  29    pointer value.  */
  30
  31 # define DISCARD_BOUNDS(rBP)                    \
  32         lwz     rBP, oVALUE(rBP)
  33
  34 /* Check low bound, with the side effect that the BP register is converted
  35    its simple pointer value.  Move the high bound into a register for
  36    later use.  */
  37
  38 # define CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH)     \
  39         lwz     rHIGH, oHIGH(rBP);              \
  40         lwz     rLOW, oLOW(rBP);                \
  41         lwz     rBP, oVALUE(rBP);               \
  42         twllt   rBP, rLOW
  43
  44 /* Check the high bound, which is in a register, using the given
  45    conditional trap instruction.  */
  46
  47 # define CHECK_BOUNDS_HIGH(rVALUE, rHIGH, TWLcc) \
  48         TWLcc   rVALUE, rHIGH
  49
  50 /* Check the high bound, which is stored at the return-value's high
  51    bound slot, using the given conditional trap instruction.  */
  52
  53 # define CHECK_BOUNDS_HIGH_RTN(rVALUE, rHIGH, TWLcc)    \
  54         lwz     rHIGH, oHIGH(rRTN);                     \
  55         TWLcc   rVALUE, rHIGH
  56
  57 /* Check both bounds, with the side effect that the BP register is
  58    converted to its simple pointer value.  */
  59
  60 # define CHECK_BOUNDS_BOTH(rBP, rLOW, rHIGH)    \
  61         CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH);     \
  62         twlge   rBP, rHIGH
  63
  64 /* Check bounds on a memory region of given length, with the side
  65    effect that the BP register is converted to its simple pointer
  66    value.  */
  67
  68 # define CHECK_BOUNDS_BOTH_WIDE(rBP, rLOW, rHIGH, rLENGTH)      \
  69         CHECK_BOUNDS_LOW (rBP, rLOW, rHIGH);                    \
  70         sub     rHIGH, rHIGH, rLENGTH;                          \
  71         twlgt   rBP, rHIGH
  72
  73 # define CHECK_BOUNDS_BOTH_WIDE_LIT(rBP, rLOW, rHIGH, LENGTH)   \
  74         CHECK_BOUNDS_LOW (rBP, rLOW, rHIGH);                    \
  75         subi    rHIGH, rHIGH, LENGTH;                           \
  76         twlgt   rBP, rHIGH
  77
  78 /* Store a pointer value register into the return-value's pointer
  79    value slot.  */
  80
  81 # define STORE_RETURN_VALUE(rVALUE)             \
  82         stw     rVALUE, oVALUE(rRTN)
  83
  84 /* Store a low and high bounds into the return-value's pointer bounds
  85    slots.  */
  86
  87 # define STORE_RETURN_BOUNDS(rLOW, rHIGH)       \
  88         stw     rLOW, oLOW(rRTN);               \
  89         stw     rHIGH, oHIGH(rRTN)
  90
  91 /* Stuff zero value/low/high into the BP addressed by rRTN.  */
  92
  93 # define RETURN_NULL_BOUNDED_POINTER            \
  94         li      r4, 0;                          \
  95         STORE_RETURN_VALUE (r4);                \
  96         STORE_RETURN_BOUNDS (r4, r4)
  97
  98 #else
  99
 100 # define DISCARD_BOUNDS(rBP)
 101 # define CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH)
 102 # define CHECK_BOUNDS_HIGH(rVALUE, rHIGH, TWLcc)
 103 # define CHECK_BOUNDS_HIGH_RTN(rVALUE, rHIGH, TWLcc)
 104 # define CHECK_BOUNDS_BOTH(rBP, rLOW, rHIGH)
 105 # define CHECK_BOUNDS_BOTH_WIDE(rBP, rLOW, rHIGH, rLENGTH)
 106 # define CHECK_BOUNDS_BOTH_WIDE_LIT(rBP, rLOW, rHIGH, LENGTH)
 107 # define STORE_RETURN_VALUE(rVALUE)
 108 # define STORE_RETURN_BOUNDS(rLOW, rHIGH)
 109
 110 # define RETURN_NULL_BOUNDED_POINTER li rRTN, 0
 111
 112 #endif