sysdeps/powerpc/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, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #if __BOUNDED_POINTERS__
  23
  24 /* Byte offsets of BP components.  */
  25 # define oVALUE 0
  26 # define oLOW   4
  27 # define oHIGH  8
  28
  29 /* Don't check bounds, just convert the BP register to its simple
  30    pointer value.  */
  31
  32 # define DISCARD_BOUNDS(rBP)                    \
  33         lwz     rBP, oVALUE(rBP)
  34
  35 /* Check low bound, with the side effect that the BP register is converted
  36    its simple pointer value.  Move the high bound into a register for
  37    later use.  */
  38
  39 # define CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH)     \
  40         lwz     rHIGH, oHIGH(rBP);              \
  41         lwz     rLOW, oLOW(rBP);                \
  42         lwz     rBP, oVALUE(rBP);               \
  43         twllt   rBP, rLOW
  44
  45 /* Check the high bound, which is in a register, using the given
  46    conditional trap instruction.  */
  47
  48 # define CHECK_BOUNDS_HIGH(rVALUE, rHIGH, TWLcc) \
  49         TWLcc   rVALUE, rHIGH
  50
  51 /* Check the high bound, which is stored at the return-value's high
  52    bound slot, using the given conditional trap instruction.  */
  53
  54 # define CHECK_BOUNDS_HIGH_RTN(rVALUE, rHIGH, TWLcc)    \
  55         lwz     rHIGH, oHIGH(rRTN);                     \
  56         TWLcc   rVALUE, rHIGH
  57
  58 /* Check both bounds, with the side effect that the BP register is
  59    converted to its simple pointer value.  */
  60
  61 # define CHECK_BOUNDS_BOTH(rBP, rLOW, rHIGH)    \
  62         CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH);     \
  63         twlge   rBP, rHIGH
  64
  65 /* Check bounds on a memory region of given length, with the side
  66    effect that the BP register is converted to its simple pointer
  67    value.  */
  68
  69 # define CHECK_BOUNDS_BOTH_WIDE(rBP, rLOW, rHIGH, rLENGTH)      \
  70         CHECK_BOUNDS_LOW (rBP, rLOW, rHIGH);                    \
  71         sub     rHIGH, rHIGH, rLENGTH;                          \
  72         twlgt   rBP, rHIGH
  73
  74 # define CHECK_BOUNDS_BOTH_WIDE_LIT(rBP, rLOW, rHIGH, LENGTH)   \
  75         CHECK_BOUNDS_LOW (rBP, rLOW, rHIGH);                    \
  76         subi    rHIGH, rHIGH, LENGTH;                           \
  77         twlgt   rBP, rHIGH
  78
  79 /* Store a pointer value register into the return-value's pointer
  80    value slot.  */
  81
  82 # define STORE_RETURN_VALUE(rVALUE)             \
  83         stw     rVALUE, oVALUE(rRTN)
  84
  85 /* Store a low and high bounds into the return-value's pointer bounds
  86    slots.  */
  87
  88 # define STORE_RETURN_BOUNDS(rLOW, rHIGH)       \
  89         stw     rLOW, oLOW(rRTN);               \
  90         stw     rHIGH, oHIGH(rRTN)
  91
  92 /* Stuff zero value/low/high into the BP addressed by rRTN.  */
  93
  94 # define RETURN_NULL_BOUNDED_POINTER            \
  95         li      r4, 0;                          \
  96         STORE_RETURN_VALUE (r4);                \
  97         STORE_RETURN_BOUNDS (r4, r4)
  98
  99 #else
 100
 101 # define DISCARD_BOUNDS(rBP)
 102 # define CHECK_BOUNDS_LOW(rBP, rLOW, rHIGH)
 103 # define CHECK_BOUNDS_HIGH(rVALUE, rHIGH, TWLcc)
 104 # define CHECK_BOUNDS_HIGH_RTN(rVALUE, rHIGH, TWLcc)
 105 # define CHECK_BOUNDS_BOTH(rBP, rLOW, rHIGH)
 106 # define CHECK_BOUNDS_BOTH_WIDE(rBP, rLOW, rHIGH, rLENGTH)
 107 # define CHECK_BOUNDS_BOTH_WIDE_LIT(rBP, rLOW, rHIGH, LENGTH)
 108 # define STORE_RETURN_VALUE(rVALUE)
 109 # define STORE_RETURN_BOUNDS(rLOW, rHIGH)
 110
 111 # define RETURN_NULL_BOUNDED_POINTER li rRTN, 0
 112
 113 #endif
 114