mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Sapphire/sh/heap

   1 ;
   2 ; heap.sh
   3 ;
   4 ; A resizing, nonshifting heap
   5 ;
   6 ; © 1994-1998 Straylight
   7 ;
   8
   9 ;----- Licensing note -------------------------------------------------------
  10 ;
  11 ; This file is part of Straylight's Sapphire library.
  12 ;
  13 ; Sapphire is free software; you can redistribute it and/or modify
  14 ; it under the terms of the GNU General Public License as published by
  15 ; the Free Software Foundation; either version 2, or (at your option)
  16 ; any later version.
  17 ;
  18 ; Sapphire is distributed in the hope that it will be useful,
  19 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ; GNU General Public License for more details.
  22 ;
  23 ; You should have received a copy of the GNU General Public License
  24 ; along with Sapphire.  If not, write to the Free Software Foundation,
  25 ; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26
  27 ;----- Overview -------------------------------------------------------------
  28 ;
  29 ; Functions provided:
  30 ;
  31 ;  heap_init
  32 ;  heap_useHeap
  33 ;  heap_info
  34 ;  heap_alloc
  35 ;  heap_free
  36 ;  heap_reAlloc
  37
  38                 [       :LNOT::DEF:heap__dfn
  39                 GBLL    heap__dfn
  40
  41 ; --- heap_init ---
  42 ;
  43 ; On entry:     --
  44 ;
  45 ; On exit:      --
  46 ;
  47 ; Use:          Initialises the heap system for use.
  48
  49                 IMPORT  heap_init
  50
  51 ; --- heap_useHeap ---
  52 ;
  53 ; On entry:     --
  54 ;
  55 ; On exit:      --
  56 ;
  57 ; Use:          Registers the resizing heap as the current allocator.
  58
  59                 IMPORT  heap_useHeap
  60
  61 ; --- heap_info ---
  62 ;
  63 ; On entry:     --
  64 ;
  65 ; On exit:      R0 == current heap size
  66 ;               R1 == amount of memory free in the heap
  67 ;               R2 == size of the largest block free
  68 ;
  69 ; Use:          Describes the heap's current status.
  70
  71                 IMPORT  heap_info
  72
  73 ; --- heap_alloc ---
  74 ;
  75 ; On entry:     R0 == size of block wanted
  76 ;
  77 ; On exit:      CC if enough memory was found and
  78 ;                 R0 == pointer to the block allocated
  79 ;               else CS and
  80 ;                 R0 corrupted
  81 ;
  82 ; Use:          Allocates a block of at least a given size from a heap.  If
  83 ;               the heap is not big enough, more is claimed from the
  84 ;               operating system.
  85
  86                 IMPORT  heap_alloc
  87
  88 ; --- heap_free ---
  89 ;
  90 ; On entry:     R0 == pointer to a block created with heap_alloc
  91 ;
  92 ; On exit:      --
  93 ;
  94 ; Use:          Frees a block allocated using heap_alloc.  It tries to
  95 ;               shrink the heap as much as possible afterwards.
  96
  97                 IMPORT  heap_free
  98
  99 ; --- heap_reAlloc ---
 100 ;
 101 ; On entry:     R0 == pointer to block whose size we want to change
 102 ;               R1 == the new size of the block
 103 ;
 104 ; On exit:      CC if block was resized, and
 105 ;                 R0 == pointer to the block (which may have moved)
 106 ;               else CS and
 107 ;                 R0 corrupted
 108 ;
 109 ; Use:          Changes the size of a heap block.  If possible, the block's
 110 ;               position is unchanged, but this may not always be the case.
 111 ;
 112 ;               Note that changing a block's size to 0 is permitted.
 113
 114                 IMPORT  heap_reAlloc
 115
 116                 ]
 117
 118 ;----- That's all, folks ----------------------------------------------------
 119
 120                 END