mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Quartz/s/screen

   1 ;
   2 ; screen.s
   3 ;
   4 ; Screen mode information caching (TMA)
   5 ;
   6 ; © 1994-1998 Straylight
   7 ;
   8
   9 ;----- Licensing note -------------------------------------------------------
  10 ;
  11 ; This file is part of Straylight's Quartz library.
  12 ;
  13 ; Quartz 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 ; Quartz 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 Quartz.  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 ;----- External dependencies ------------------------------------------------
  33 ;
  34 ; None.
  35
  36 ;----- Main code ------------------------------------------------------------
  37
  38                 AREA    |Quartz$$Code|,CODE,READONLY
  39
  40 ; --- screen_getInfo ---
  41 ;
  42 ; On entry:     --
  43 ;
  44 ; On exit:      R0 == pointer to screen information block
  45 ;
  46 ; Use:          This call returns a pointer to a block of information
  47 ;               about the current screen modes. The offset for different
  48 ;               bits of data are defined in screen.sh
  49
  50                 EXPORT  screen_getInfo
  51 screen_getInfo  ROUT
  52
  53                 LDR     R0,screen__wSpace       ;Get my workspace
  54                 ADD     R0,R0,#4                ;Point to the data block
  55                 MOVS    PC,R14                  ;Return to caller
  56
  57                 LTORG
  58
  59 ; --- screen__cache ---
  60 ;
  61 ; On entry:     --
  62 ;
  63 ; On exit:      --
  64 ;
  65 ; Use:          Caches screen information for the current mode
  66
  67 screen__cache   ROUT
  68
  69                 STMFD   R13!,{R0-R10,R14}       ;Stack some registers
  70                 LDR     R12,screen__wSpace      ;Locate my workspace
  71
  72                 ; --- Now read relevent mode variables ---
  73
  74                 MOV     R3,#1                   ;A useful value
  75                 MOV     R0,#-1                  ;Get info on current mode
  76
  77                 MOV     R1,#4                   ;XEigFactor
  78                 SWI     OS_ReadModeVariable     ;Read its value
  79                 MOV     R4,R2                   ;Look after xEig
  80                 MOV     R9,R3,LSL R4            ;Get dx correctly
  81
  82                 MOV     R1,#5                   ;YEigFactor
  83                 SWI     OS_ReadModeVariable     ;Read its value
  84                 MOV     R5,R2                   ;Look after yEig
  85                 MOV     R10,R3,LSL R5           ;Get dy correctly
  86
  87                 MOV     R1,#9                   ;Log2BPP
  88                 SWI     OS_ReadModeVariable     ;Read its value
  89                 MOV     R6,R3,LSL R2            ;Calculate bpp
  90
  91                 MOV     R1,#11                  ;XWindLimit
  92                 SWI     OS_ReadModeVariable     ;Read its value
  93                 ADD     R2,R2,#1                ;Calculate screen width
  94                 MOV     R7,R2,LSL R4            ;width=(XwindLimit+1)<<xEig
  95
  96                 MOV     R1,#12                  ;XWindLimit
  97                 SWI     OS_ReadModeVariable     ;Read its value
  98                 ADD     R2,R2,#1                ;Calculate screen width
  99                 MOV     R8,R2,LSL R5            ;height=(YwindLimit+1)<<yEig
 100
 101                 ; --- Now store the cached information ---
 102
 103                 STMIB   R12,{R4-R10}            ;Store in my workspace
 104
 105                 ; --- And return to caller ---
 106
 107                 LDMFD   R13!,{R0-R10,PC}^       ;Return
 108
 109                 LTORG
 110
 111 ; --- screen_init ---
 112 ;
 113 ; On entry:     R12 == pointer to private workspace
 114 ;
 115 ; On exit:      --
 116 ;
 117 ; Use:          Initialises the ptr system
 118
 119                 EXPORT  screen_init
 120 screen_init     ROUT
 121
 122                 STMFD   R13!,{R0,R14}           ;Stack some registers
 123
 124                 ; --- Are we already initialised? ---
 125
 126                 LDR     R0,screen__flags        ;Get my flags
 127                 TST     R0,#sFlag__inited       ;Are we initialised?
 128                 LDMNEFD R13!,{R0,PC}^           ;Yes -- return
 129
 130                 ORR     R0,R0,#sFlag__inited    ;Set flags
 131                 STR     R0,screen__flags        ;And store them back
 132
 133                 ; --- Now cache the current mode info ---
 134
 135                 BL      screen__cache           ;Cache screen information
 136
 137                 ; --- That's it now ---
 138
 139                 LDMFD   R13!,{R0,PC}^           ;Return
 140
 141                 LTORG
 142
 143 screen__wSpace  DCD     0                       ;My workspace pointer
 144
 145 ;----- Workspace ------------------------------------------------------------
 146
 147                 ^       0,R12
 148 screen__wStart  #       0
 149
 150 screen__flags   #       4                       ;Flags
 151
 152 screen__xEig    #       4                       ;X Eig Factor
 153 screen__yEig    #       4                       ;Y Eig Factor
 154 screen__bpp     #       4                       ;Bits per pixel
 155 screen__width   #       4                       ;Current screen width
 156 screen__height  #       4                       ;Current screen height
 157 screen__dx      #       4                       ;x pixel size
 158 screen__dy      #       4                       ;y pixel size
 159
 160 screen__wSize   EQU     {VAR}-screen__wStart
 161
 162 sFlag__inited   EQU     (1<<0)                  ;I've been initialised
 163
 164                 AREA    |Quartz$$Service|,CODE,READONLY
 165
 166                 DCD     screen__cache,&46
 167
 168                 AREA    |Quartz$$Table|,CODE,READONLY
 169
 170                 DCD     screen__wSize           ;Workspace size
 171                 DCD     screen__wSpace          ;Workspace pointer
 172                 DCD     screen_init             ;Initialisation code
 173                 DCD     0                       ;Finalisation
 174
 175 ;----- That's all, folks ----------------------------------------------------
 176
 177                 END