mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Sapphire/s/libOpts

   1 ;
   2 ; libOpts.s
   3 ;
   4 ; Allow options for library units to be declared
   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 ;----- Standard header ------------------------------------------------------
  28
  29                 GET     libs:header
  30                 GET     libs:swis
  31
  32                 GET     libs:stream
  33
  34 ;----- External dependencies ------------------------------------------------
  35
  36                 GET     sapphire:sapphire
  37                 GET     sapphire:suballoc
  38
  39 ;----- Main code ------------------------------------------------------------
  40
  41                 AREA    |Sapphire$$Code|,CODE,READONLY
  42
  43 ; --- libOpts_register ---
  44 ;
  45 ; On entry:     R0 == address of an options block
  46 ;
  47 ; On exit:      --
  48 ;
  49 ; Use:          Adds the block given to the library options.
  50
  51                 EXPORT  libOpts_register
  52 libOpts_register ROUT
  53
  54                 STMFD   R13!,{R0,R1,R12,R14}    ;Save some registers
  55                 WSPACE  lo__wSpace              ;Locate my workspace
  56
  57                 BL      sub_init                ;Awaken suballoc just in case
  58                 MOV     R1,R0                   ;Look after the block addr
  59                 MOV     R0,#8                   ;Allocate a small link block
  60                 BL      sub_alloc               ;Try to allocate memory
  61                 LDMVSFD R13!,{R0,R1,R12,PC}^    ;If it failed, don't bother
  62
  63                 STR     R1,[R0,#0]              ;Remember this block pointer
  64                 LDR     R14,lo__head            ;Load the current list head
  65                 STR     R14,[R0,#4]             ;Save this as the next link
  66                 STR     R0,lo__head             ;And save new list head
  67                 LDMFD   R13!,{R0,R1,R12,PC}^    ;And return to caller
  68
  69                 LTORG
  70
  71 ; --- libOpts_find ---
  72 ;
  73 ; On entry:     R0 == magic marker word
  74 ;
  75 ; On exit:      CS if found, and
  76 ;                 R0 == address of options block
  77 ;               else CC, and
  78 ;                 R0 corrupted
  79 ;
  80 ; Use:          Tries to find an option with the given marker, which will
  81 ;               normally be a four-character text string.  The first match
  82 ;               found will be returned.  The options blocks are searched in
  83 ;               reverse order of registration (i.e. blocks registered later
  84 ;               will override blocks registered reviously).
  85
  86                 EXPORT  libOpts_find
  87 libOpts_find    ROUT
  88
  89                 STMFD   R13!,{R1-R3,R12,R14}    ;Save some registers away
  90                 WSPACE  lo__wSpace              ;Find my workspace
  91                 MOV     R2,R0                   ;Look after the marker
  92                 LDR     R1,lo__head             ;Load the list head block
  93
  94                 ; --- Scan through the list ---
  95
  96 10libOpts_find  CMP     R1,#0                   ;Reached the end yet?
  97                 BEQ     %50libOpts_find         ;Yes -- return to caller
  98                 LDMIA   R1,{R0,R1}              ;Load the block ptr and link
  99
 100                 ; --- See if we can find it in here ---
 101
 102 20libOpts_find  LDMIA   R0!,{R3,R14}            ;Load marker and size word
 103                 CMP     R2,R3                   ;Does this match up?
 104                 BEQ     %40libOpts_find         ;Yes -- found it then
 105                 CMP     R3,#-1                  ;Is this the block end?
 106                 ADDNE   R0,R0,R14               ;No -- move on to next item
 107                 BNE     %20libOpts_find         ;And loop round again
 108                 B       %10libOpts_find         ;Try the next options block
 109
 110                 ; --- Found a match ---
 111
 112 40libOpts_find  LDMFD   R13!,{R1-R3,R12,R14}    ;Restore registers
 113                 ORRS    PC,R14,#C_flag          ;Return successfully
 114
 115                 ; --- Failed to find a match ---
 116
 117 50libOpts_find  LDMFD   R13!,{R1-R3,R12,R14}    ;Restore registers
 118                 BICS    PC,R14,#C_flag          ;Return unsuccessfully
 119
 120                 LTORG
 121
 122 lo__wSpace      DCD     0
 123
 124 ;----- Workspace ------------------------------------------------------------
 125
 126                 ^       0,R12
 127 lo__wStart      #       0
 128
 129 lo__head        #       4                       ;Base of the options list
 130
 131 lo__wSize       EQU     {VAR}-lo__wStart
 132
 133                 AREA    |Sapphire$$LibData|,CODE,READONLY
 134
 135                 DCD     lo__wSize
 136                 DCD     lo__wSpace
 137                 DCD     0
 138                 DCD     0
 139
 140 ;----- That's all, folks ----------------------------------------------------
 141
 142                 END